Record completed v0.6.30 release validation

CMakeLists.txt

@@ -1,14 +1,14 @@
 cmake_minimum_required(VERSION 3.24)
-project(KSwitcher VERSION 0.6.20 LANGUAGES CXX RC)
+project(KSwitcher VERSION 0.6.30 LANGUAGES CXX RC)
 if(NOT WIN32)
   message(FATAL_ERROR "KSwitcher uses native Windows APIs")
 endif()
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
-add_library(kscore src/core.cpp src/platform.cpp src/autostart.cpp src/autocorrect.cpp src/storage.cpp src/ocr.cpp src/richtext.cpp src/update.cpp)
+add_library(kscore src/core.cpp src/platform.cpp src/autostart.cpp src/autocorrect.cpp src/storage.cpp src/ocr.cpp src/richtext.cpp src/update.cpp src/sync.cpp)
 target_include_directories(kscore PUBLIC src PRIVATE vendor)
 target_compile_definitions(kscore PUBLIC UNICODE _UNICODE WIN32_LEAN_AND_MEAN NOMINMAX _WIN32_WINNT=0x0A00)
-target_link_libraries(kscore PUBLIC user32 shell32 shlwapi advapi32 crypt32 imm32 comctl32 gdi32 ole32 oleaut32 taskschd comdlg32 uuid windowscodecs runtimeobject uiautomationcore)
+target_link_libraries(kscore PUBLIC winhttp user32 shell32 shlwapi advapi32 crypt32 imm32 comctl32 gdi32 ole32 oleaut32 taskschd comdlg32 uuid windowscodecs runtimeobject uiautomationcore)
 add_executable(KSwitcher WIN32 src/main.cpp src/app.cpp src/screenshot_notifications.cpp src/screenshot_launcher.cpp src/screenshot_activation.cpp src/configuration.cpp src/ui.cpp resources/app.rc)
 target_compile_definitions(KSwitcher PRIVATE KS_RESIDENT_APP)
 target_link_libraries(KSwitcher PRIVATE kscore)
@@ -17,6 +17,14 @@ set_target_properties(KSwitcherConfig PROPERTIES OUTPUT_NAME "KSwitcher.Config")
 target_compile_definitions(KSwitcherConfig PRIVATE KS_CONFIG_APP)
 target_link_libraries(KSwitcherConfig PRIVATE kscore)
 add_executable(KSwitcherTests tests/tests.cpp)
+add_executable(KSwitcherSyncTests tests/sync.cpp)
+target_include_directories(KSwitcherSyncTests PRIVATE vendor)
+target_link_libraries(KSwitcherSyncTests PRIVATE kscore)
+if(MSVC)
+  set_property(TARGET KSwitcherSyncTests PROPERTY MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
+else()
+  target_link_options(KSwitcherSyncTests PRIVATE -static -static-libgcc -static-libstdc++)
+endif()
 add_executable(KSwitcherScrollTests tests/scroll.cpp)
 target_link_libraries(KSwitcherScrollTests PRIVATE kscore)
 target_link_libraries(KSwitcherTests PRIVATE kscore)
@@ -57,10 +65,12 @@ else()
   target_link_options(KSwitcherOcrTests PRIVATE -static -static-libgcc -static-libstdc++)
 endif()
 enable_testing()
+add_test(NAME sync-regressions COMMAND KSwitcherSyncTests)
 add_test(NAME native-regressions COMMAND KSwitcherTests)
 add_test(NAME scroll-regressions COMMAND KSwitcherScrollTests)
 add_test(NAME input-regressions COMMAND KSwitcherInputTests)
 add_test(NAME screenshot-ui-regressions COMMAND KSwitcherScreenshotUITests)
+add_test(NAME screenshot-save-regressions COMMAND KSwitcherScreenshotUITests --save-only)
 add_test(NAME updater-regressions COMMAND powershell.exe -NoProfile -ExecutionPolicy Bypass -File "${CMAKE_CURRENT_SOURCE_DIR}/tests/update.ps1" -Executable "$<TARGET_FILE:KSwitcher>")
 set_tests_properties(native-regressions PROPERTIES WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}")
 install(TARGETS KSwitcher KSwitcherConfig KSwitcherScreenshot RUNTIME DESTINATION .)

README.md

@@ -16,6 +16,11 @@ Run `build/KSwitcher.exe`, or extract `dist/KSwitcher-win-x64.zip` and run the e
 The build also refreshes the release copy in `build/release/`. Exit KSwitcher before rebuilding.
 The application lives in the notification area. Right-click its icon for Settings, Snippets and history.
 Double-click the tray icon to open Settings, the bold default menu item.
+Menus support access keys: press the underlined letter while the menu is open (for example,
+S for Settings or X for Exit in the tray menu). In forms, press Alt+the underlined letter
+to activate a button, toggle a checkbox or focus a labeled field. Press Alt to reveal
+the underlines when Windows hides them. Shortcut-capture fields still record Alt combinations;
+press Tab to leave a shortcut field before using form access keys.
 Settings, the snippet editor and log viewer run on demand in **KSwitcher.Config.exe**, beside the main executable.
 Repeated launches activate the existing configurator; closing its last window exits that process.
 Saving applies changes immediately through the resident KSwitcher process. The configurator does not
@@ -90,6 +95,10 @@ broker can load them even when the profile directory is inaccessible to it.
 Notifications expire after 24 hours. Cache cleanup runs on capture/open; each cache is bounded to
 40 files and 256 MiB. Expired or evicted notifications cannot reopen their screenshot.
 In the editor, **Ctrl+C** or **Enter** copies the current result without closing the window.
+**Save… / Ctrl+S** saves the full-resolution image and annotations as PNG. The first save asks
+for a file; later saves update that file. **Ctrl+Shift+S (Save As…)** always asks for a new
+destination. Saving keeps the editor open and leaves the clipboard unchanged. Further edits
+must be saved or copied again before closing without a warning.
 The editor starts with **Pencil / Freehand (F)** for drawing. Choose **Pointer (V)** to select objects, move them, and edit geometry, thickness and
 other properties using handles and controls. Clicking empty space clears selection; dragging empty
 space adds nothing. Choose a drawing tool to create objects, then return to **V** to edit them.
@@ -107,10 +116,10 @@ change its diameter. Wheel up increases the size; wheel down decreases it. These
 and update linked arrows. **Ctrl+D** clones the selected object with a small offset. A cloned number
 gets the smallest available positive number, just like a newly placed number: gaps left by deletion
 are filled first, without renumbering existing objects. A cloned arrow keeps its style but starts without endpoint links.
-Arrow and line endpoints can attach to numbered markers, rectangles, circles, ellipses, text blocks,
+Arrow and line endpoints can attach to numbered markers, rectangles, circles, ellipses, triangles, trapezoids, text blocks,
 and other arrows or strokes. In Arrow or Straight line mode, hold **Ctrl** and drag from one object
 to another to draw over them and automatically attach both endpoints. Without Ctrl, existing objects
-can still be selected and edited as before. With Pointer, drag an existing endpoint onto a target to attach it. Attached endpoints follow movement and resizing; text attachments
+can still be selected and edited as before. With Pointer, drag an existing endpoint onto a target to attach it. Attached endpoints follow movement and resizing; shape and text attachments
 also follow rotation. Arrow-to-arrow attachments retain their relative position along the target line.
 Clicking a connector or adding/editing its caption preserves its links. Moving the whole connector
 intentionally detaches its endpoints; moving one endpoint detaches only that end. Deleting a target
@@ -158,7 +167,37 @@ resize; circles keep equal width and height. Move shapes by their outlines, adju
 the mouse wheel or side handle, recolor, clone with Ctrl+D, and undo/redo as with other objects.
 Hold Ctrl to start drawing over an existing object. Line style applies to outlines; Ends is disabled
 for shapes.
+**Canvas zoom:** use **Ctrl++ / Ctrl+-** (including numpad keys) or **Ctrl+mouse wheel**.
+Each step changes the view by 25%; the wheel zooms around the cursor, keyboard shortcuts around
+the viewport center. **Ctrl+0** restores the initial fit. Drag with the **middle mouse button**
+to pan an enlarged image. Zoom ranges from 0.1× to 16× the initial fit; the status bar shows the
+actual image scale. Zoom and pan do not change annotations, export resolution or undo history.
+The wheel without Ctrl still adjusts the object under the cursor.
+
 **Freehand line (F)** draws an opaque curve by following the mouse. The curve is one object:
+after mouse release, nearly straight strokes become editable straight lines at their drawn angle,
+preserving endpoints, color, thickness, line style and arrowheads. Short strokes, broad curves and
+retraced strokes are not straightened. Other strokes receive light smoothing to reduce jitter.
+Confidently recognized closed outlines become
+rectangles, circles, ellipses, triangles or trapezoids (including tilted outlines), stored as shape objects.
+Drag either bounding-box corner handle to resize the entire recognized outline; circles keep equal
+width and height. Shapes can also be moved, recolored and cloned.
+Every shape has a round rotation handle above its outline. Drag it to rotate around the center;
+hold **Shift** for 15-degree steps. The handle works for toolbar shapes and recognized shapes,
+including triangles. Resize handles and attached connectors follow the rotation; Ctrl+Z/Ctrl+Y
+undo and redo it. The square handle still controls outline thickness.
+**Triangle (G)** is also available directly on the toolbar: drag to create a triangle.
+Both drawn and recognized triangles have three independent vertex handles instead of bounding-box
+resize handles. Drag any vertex to reshape the triangle while keeping the other two fixed, even
+after rotation. Vertex edits support undo/redo, and the rotation and thickness handles remain available.
+**Trapezoid (B)** on the toolbar creates a trapezoid with parallel bases. Pencil recognition also
+fits nearly parallel, unequal bases into a clean trapezoid. Trapezoids support bounding-box resizing,
+rotation, styling and undo/redo; Ctrl+Z after recognition restores the original pencil stroke.
+Oval fitting tolerates uneven contours and small closing gaps or overlaps; broad open arcs and
+repeated loops remain freehand strokes.
+Press **Ctrl+Z** once to restore the original stroke, again to remove it; **Ctrl+Y** reapplies the improvement.
+Small strokes, strokes linked to other objects, and any stroke drawn partly with Shift are left unchanged.
+Ambiguous shapes are only smoothed. To edit the resulting curve,
 move it, change its color or thickness, clone it, or drag its endpoints. Hold Ctrl to start a new
 stroke over an existing object. Hold **Shift** while drawing to constrain the current segment
 to a horizontal, vertical or 45-degree diagonal line; release Shift to resume freehand drawing in the same stroke.
@@ -168,7 +207,7 @@ released repeatedly within one stroke. The **Line style** selector supports Soli
 Dash-dot; **Ends** supports an arrow at the end, start, both ends, or no arrows. These settings
 apply to selected straight/freehand lines and set defaults for subsequent lines. Both are disabled
 for numbered markers and highlights unless a line drawing tool is active. Undo/Redo includes style changes.
-The window close button asks for confirmation before discarding an uncopied screenshot.
+The window close button asks for confirmation before discarding changes that have not been saved or copied.
 **Escape** cancels region selection or inline text edits; it does not close the editor. Copy keeps the editor open and publishes the image
 at its original pixel size, ready to paste. The preview fits the window without changing export size.
 The shortcut is configurable in Settings under **Screen capture**.
@@ -220,6 +259,10 @@ thumbnails and source labels aligned with the scaled fonts and spacing.
 ## Implemented
 
 - Installed Windows keyboard layouts, configurable cycle/order and direct shortcuts; IMEs are switch-only.
+  Text conversion cycles skip layouts that leave the text unchanged and use the next enabled layout
+  that changes it. If none changes the text, the operation keeps the text and advances one layout.
+  Partial copied suffixes can be reselected with paced keys; replacement still requires verification
+  of the complete expected text. Browser/editor compatibility depends on its handling of simulated input.
 - Selection conversion and verified recent input (physical scan codes, 2-second typing-run boundary).
 - Same-process clipboard ownership plus verified WebView2 descendants, including the Teams fix.
 - Teams recent-word conversion uses a single word-selection command and validates the copied range.
@@ -228,7 +271,11 @@ thumbnails and source labels aligned with the scaled fonts and spacing.
 - Clipboard snapshot/restoration with concurrent-copy, foreground and input-version checks.
   A silently dropped copy is retried up to three total attempts while the clipboard and input
   context remain unchanged. Temporary transaction contents are excluded from Windows clipboard
-  history and cloud synchronization. Paste is not blindly retried.
+  history and cloud synchronization. Paste is not blindly retried: with manual paste readback
+  enabled by Write log, a native Windows EDIT gets at most one retry when readback reports the
+  original and fresh native queries confirm that exactly the original range is still selected.
+  Other controls and unknown/changed selections are not retried. A verified failed paste clears
+  repeat-conversion state and does not switch the Windows layout.
 - Case cycling, Russian/Ukrainian transliteration, verified undo and repeated conversion.
 - Text snippets across layouts, multiline insertion and a verified `{cursor}` position;
   `{enter}` presses Enter after insertion and cursor placement (once per marker), before buffered typing resumes.
@@ -278,21 +325,16 @@ existing saved shortcuts are preserved. While KSwitcher runs, this binding opens
 
 History controls: Enter to paste, Shift+Enter for plain text, Ctrl+1…9 for quick paste,
 Ctrl+P to pin/unpin, Delete to delete, Ctrl+O for the full item, Escape to hide.
+
+**Clear history… / Alt+H** in the history window clears all saved entries after confirmation,
+including pinned entries and entries hidden by search. No is the default choice. The current
+Windows clipboard and future recording are unchanged. Settings also retains its Clear history action.
 For an image, **Edit image**, **Ctrl+O**, or **Edit image in screenshot editor**
 in the context menu opens the original image in the built-in screenshot editor.
 Annotate it there, then copy the result. Opening the editor leaves the
 clipboard and original history entry unchanged. Text items still open as text;
 Enter and double-click still paste the selected item.
 
-Local builds made with `build.ps1` show **[LOCAL DEV]** in window titles and
-the tray tooltip. The marker is enabled by `.local-dev` beside the executable;
-release packages do not include that marker.
-
-Fast/inertial wheel events use a shared batching handler in history, layout and
-snippet lists, the log table, multiline text/details fields, combo boxes and
-scrollable settings windows. High-resolution partial wheel steps are retained.
-History pauses new preview loads while scrolling and keeps visible thumbnails
-cached, preventing continuous flicker and needless redraws.
 Pressing the history shortcut a second time pastes the second-most-recent item.
 
 ## Data and migration
@@ -302,7 +344,14 @@ the executable's directory is not writable. Each clipboard payload is an encrypt
 only bounded previews/metadata stay in memory. Image data is loaded on demand and released when
 the history popup is hidden. Settings **Write log** (`writeLog`, enabled by default) controls all
 log writes. Disabling it also clears diagnostic context from memory; existing log files remain.
-Diagnostic stages stay in a memory buffer of at most 40 events for 30 seconds.
+Diagnostic stages stay in a memory buffer of at most 128 events for 30 seconds.
+Selection diagnostics include the expected text, each copied candidate before and after suffix
+recovery, paced Shift+Left progress or batch delivery counts, and clipboard sequence changes,
+retry counts and elapsed times. Focus, caret geometry and keyboard layout are recorded when
+Windows exposes them; selection offsets are available for native EDIT controls and explicitly
+marked unavailable for other editors. Input interruptions identify keyboard, mouse, settings
+or layout-refresh events during an operation. Failed selection verification includes the expected
+selection and actual copied text in the operation details, without implying that a paste occurred.
 Only problem operations write a structured summary to `kswitcher.log`, with their preceding
 context. Successful operations stay in that bounded memory buffer and are included only when
 a subsequent problem flushes it; they do not create separate rows. Flushed context is discarded. Ordinary application
@@ -354,6 +403,119 @@ This is a working native implementation, not a claim of complete UI/release pari
 The Windows focus/injection rules still apply: an unelevated process cannot edit an elevated app.
 Conversion is cancelled rather than pasting into a different window or replacing unverified recent text.
 
+## OpenBao synchronization (experimental, opt-in)
+
+The **Sync...** button is available in Settings for everyone. Synchronization remains disabled
+until you configure your own OpenBao and enable it. Connection configuration is saved separately
+in `sync.json`. The portable data directory is normally `data/` beside the executable; installations
+without a writable application directory use the existing local-app-data fallback.
+No server address or account is included in the application.
+
+The first provider is **OpenBao KV v2**. The dialog accepts an HTTPS server origin, username,
+password, KV mount (default `kswitcher`), profile path (default `personal/settings`) and userpass
+authentication mount (default `userpass`). Use the same profile on each of your PCs. This is
+administrator-provisioned private access, not public account registration. Non-root namespaces,
+reverse-proxy URL prefixes, MFA login flows and other providers are not implemented yet.
+
+Enable synchronization and choose **Save / Sign in / Sync**. The dialog saves connection changes
+immediately; the main Settings window's Save/Cancel does not control this separate configuration.
+When synchronization is disabled, connection fields and sync actions are inactive. Check **Enable
+synchronization** to make them available. To disable an existing connection, uncheck it and click
+**Save**; this preserves the saved connection and password without starting a sync request.
+**Disconnect / forget password** remains available while synchronization is disabled.
+A blank password keeps the existing Windows credential for that server, login mount and username.
+The password is saved in Windows Credential Manager, not in settings exports, logs or the remote
+profile. HTTPS certificate validation is mandatory and redirects are refused. Login tokens are
+kept in memory for one sync attempt, with best-effort self-revocation afterwards. Configure bounded
+token lifetimes on the server as well (for example a 5-minute default and 10-minute maximum).
+**Disconnect / forget password** disables synchronization and removes the current connection's
+saved credential. A request already sent to the server may still complete; its downloaded settings
+will not be applied after the connection changes. Old credentials for other connection identities
+can be removed in Windows Credential Manager under `KSwitcher.Sync/`.
+
+On the first connection, **Save / Sign in / Sync** merges the existing profiles without
+requiring a whole-profile replacement. Independent entries (such as snippets, exclusions and
+replacement pairs) are combined. Different values for the same setting remain on their respective
+sides and appear in **Resolve individual conflicts...**; no value is guessed without a common history.
+Nonconflicting changes synchronize immediately, and unresolved conflicts survive subsequent syncs.
+
+- **Upload local** creates the remote profile or replaces it with this PC's saved shared settings.
+- **Download remote** replaces this PC's shared settings with the server profile.
+- If the server has no profile yet, choose **Upload local** to create it.
+- Unsaved edits in Settings are not synchronized. Close and reopen Settings after a download;
+  the existing stale-editor check prevents an old Settings window overwriting downloaded changes.
+
+Once connected, the resident checks at startup, every **10 minutes**, and about two seconds after saving settings, on a separate
+network thread. Errors back off for 15 minutes; the Sync button allows a manual retry. Local use
+continues offline. Independent changes to different settings fields are merged against the last
+successful baseline. **Resolve individual conflicts...** shows the name and local/server values
+for each conflict. Choose either value for selected settings and apply your choices; unselected
+conflicts stay pending. Other, nonconflicting changes continue to synchronize. Choices are checked
+against freshly read values before writing, so a stale dialog cannot overwrite a newer edit.
+Conflicting shortcuts are separate settings, including bindings for individual keyboard layouts.
+Exclusions and personal dictionary words merge by membership. Ordered layout/dictionary lists
+remain single settings because their ordering affects behavior.
+
+Snippets have persistent IDs that survive renaming. Different snippets merge independently;
+trigger and text edits within a snippet can merge too. Deleting a snippet retains a deletion
+marker, so an unchanged offline copy cannot bring it back. Deletion versus a concurrent edit
+is an explicit conflict, offering the deleted or edited version. Duplicate triggers and shortcut
+collisions created by independent edits are also presented for resolution. Deletion markers are
+retained without automatic expiry; recreating a snippet in the editor gives it a new ID.
+
+Existing profiles migrate automatically: legacy snippet IDs derive deterministically from the
+original trigger, then are stored permanently. Sync writes use envelope version 2; older clients
+refuse this version instead of dropping IDs/deletions. Update all participating PCs before using
+the new merge behavior. Existing version-1 profiles and local baselines remain readable.
+
+Download/Upload are still available for deliberate whole-profile recovery/initialization, not
+required for ordinary conflicts. Every server write uses the version just read as a CAS
+condition, including explicit Upload. A racing write is rejected rather than silently overwritten.
+Deleted server versions are not silently recreated.
+
+Hotkeys, snippets, application exclusions, layout order, conversion, screenshot and autocorrection
+preferences are shared. Startup/elevation, keep-awake, logging, history enablement/limits,
+Tesseract executable/engine selection, connection details and credentials stay local. Clipboard
+history, screenshots and dictionary files are never uploaded. Full synchronization identifies
+missing keyboard layouts by language (when Windows can identify it) and exact ID.
+Install the same layout variant, or select **Keep this PC's layouts and layout shortcuts (sync
+other settings)** and click **Save / Sign in / Sync**. This device-local option keeps the entire
+local layout cycle and its direct shortcuts unchanged while synchronizing the other shared settings.
+The server's layout cycle and direct shortcuts are preserved on automatic sync and explicit Upload;
+Download also keeps the local layout configuration. Later syncs cannot erase missing server layouts
+just because this PC does not have them installed. Uncheck the option to resume full layout sync.
+Settings are JSON inside OpenBao; this is not end-to-end encryption from the vault administrator.
+
+The last common profile (`sync-base.bin`) and the settings preceding the most recent downloaded
+change (`settings-before-sync.bin`) are protected with Windows DPAPI and belong to this Windows
+account/machine. Reinstallation recovery uses the remote profile and a fresh login; copying these
+local DPAPI files to a new machine does not recover them. For an older server snapshot, use OpenBao
+KV version history to restore that snapshot as the latest version, then choose Download remote.
+The app does not yet provide a server-history browser. Keep ordinary server backups too.
+
+OpenBao administrator setup:
+
+1. Enable a KV **version 2** engine at `kswitcher`; enable **Require Check-and-Set** and set
+   maximum versions to a suitable value, such as 30.
+2. Create a dedicated userpass account, with a policy restricted to the chosen profile. Do not
+   use the administrator account. For the defaults, the application needs only:
+
+   ```hcl
+   path "kswitcher/data/personal/settings" {
+     capabilities = ["create", "read", "update"]
+   }
+   path "auth/token/revoke-self" {
+     capabilities = ["update"]
+   }
+   ```
+
+3. Set bounded token lifetimes on that account/auth mount and enter its credentials in KSwitcher.
+   Keep the server's address and TLS certificate reachable/trusted on each participating PC.
+
+`SyncProvider` separates versioned read/conditional-write operations from merging, local state
+and UI integration, so another service can be added without replacing the synchronization logic.
+Protocol and conflict regressions run with `build.ps1 -Test` or CMake's `sync-regressions` test.
+
 ## Build
 
 The easiest reproducible local route uses the pinned portable w64devkit toolchain:
@@ -373,13 +535,40 @@ Alternatively open this directory as a CMake project in Visual Studio with the C
 and Windows SDK installed, or use CMake with a Windows GCC toolchain. CMake/MSVC is provided but the
 verified local build uses GCC/w64devkit.
 
-## Automatic layout correction (experimental)
+## Automatic correction (experimental)
 
-Enable **Automatically correct layout (experimental)** in Settings, then use **Auto-correction
+Enable **Automatic correction (experimental)** in Settings, then use **Auto-correction
 options…** to select dictionary languages and edit excluded applications or words to never correct.
 The feature is off by default. English and Ukrainian are selected initially; Russian is optional.
 Target layouts must also be enabled in the layout cycle.
 
+### Custom replacements and spelling typos
+
+Two optional modes in **Auto-correction options…** extend layout correction. Both are off by
+default and require the main **Automatic correction (experimental)** checkbox to be enabled.
+
+- **Use custom replacements**: enter one `typo=correction` pair per line, for example
+  `првиіт=привіт` or `helo=hello`. Entries are normalized to lowercase; duplicate source words
+  are rejected. Each side must contain 1–32 letters of the same supported language, without
+  spaces or punctuation. Explicit pairs take priority over dictionary recognition, including
+  already valid words, and do not require dictionary membership or satisfy the frequency limit.
+- **Correct spelling typos using dictionaries**: checks unknown words in the current language
+  after no layout correction is found. It accepts exactly one dictionary candidate reachable
+  by inserting, deleting or replacing one letter, or swapping two adjacent letters. Both input
+  and target must have at least four letters. Multiple candidates leave the input unchanged,
+  even if a frequency limit would exclude one of them. Personal dictionary words participate.
+  This is word-level spelling correction, not grammar or sentence-context correction.
+
+Both modes run after Space, preserve surrounding punctuation and an initial capital, and keep
+the current layout. The selected dictionary languages, enabled layout cycle, minimum input
+length, excluded applications, never-correct list, protected fields and Undo behavior apply.
+ALL CAPS, mixed-case identifiers, numbers, URLs and email addresses are skipped. A replacement
+is applied once, without chaining. Click **OK**, then **Save** in Settings; pairs and switches
+are included in settings export/import and synchronization. Undo restores the original word
+and suppresses its correction until restart.
+
+### Layout correction and shared options
+
 **Characters before a word** and **Characters after a word** configure punctuation to preserve around
 the corrected word. Enter characters directly, without spaces or separators; a comma or semicolon
 is itself a character. Defaults include parentheses, square/curly brackets, quotation marks and common
@@ -394,6 +583,8 @@ protect already valid input, and ambiguous alternatives remain unchanged regardl
 **My dictionary** provides separate English, Ukrainian and Russian fields for correct words missing
 from the bundled dictionaries. Enter words separated by commas or new lines, then click OK and Save
 in Settings. Case and duplicates are normalized automatically; no file editing or ranks are needed.
+The v0.6.23 bundled Ukrainian dictionary includes `поточні`. The updater preserves existing dictionary files;
+if upgrading from an older dictionary, add this word in My dictionary → Ukrainian and click OK → Save.
 These entries are stored in settings and survive dictionary updates. They protect correct input and
 are eligible as correction targets at any frequency limit. The language and target layout must still
 be enabled. **Never correct these words** is a separate exception list and takes precedence.

Release/README.md

@@ -1,24 +1,23 @@
 # Latest Windows release
 
-## v0.6.20 — 2026-10-31
+## v0.6.30 — 2026-11-02
 
 ## Changes
-- Open clipboard-history images in the built-in screenshot editor with **Edit image**, **Ctrl+O**, or **Edit image in screenshot editor** in the context menu. PNG, DIB and DIBV5 open at full resolution through an encrypted local cache, without requiring notifications or changing the clipboard/original history entry. Copy the annotated result explicitly from the editor.
+- A manual paste confirmed unsuccessful by readback no longer records the expected replacement as a previous result or switches the Windows layout. This prevents repeated commands from searching for text that was never inserted.
-- Fix continuous history flicker by keeping visible previews cached, invalidating only completed preview rows and preserving the top entry across background refreshes.
+- A previous-result verification mismatch clears stale repeat-conversion state.
-- Handle fast/inertial wheels through one shared batching mechanism for history, layout/snippet lists, the log table, multiline text/details fields, combo boxes and scrollable settings windows. Preserve partial wheel deltas, clamp list boundaries and pause new history previews until scrolling stops.
+- A writable native Windows EDIT field may receive one guarded paste retry: readback must equal the original text, and fresh native checks must confirm the exact original selection, unchanged focus and input context. Other controls, protected/read-only fields and unknown/changed selections are not retried.
-- Mark local developer builds with **[LOCAL DEV]** in window titles and the tray tooltip. Release packages omit the development marker. This does not create a separate data profile.
+- The guarded retry and failed-paste readback handling require **Write log**, which enables manual-conversion readback. Clipboard restoration remains conditional on ownership.
-- Right-clicking a history entry selects that entry before showing its actions. Enter and double-click continue to paste; text items still open in the full-text viewer.
 
 ## Validation
-Passed 406 native regressions, 473 input/UI checks, shared wheel batching tests, screenshot editor UI, notification registration, 48 updater checks and updater progress checks. Manual testing confirmed image editing from history and resolved clipboard flicker and Logitech inertial-wheel beeping. Shared wheel tests cover lists, edits, tables, combo boxes and windows, partial steps, large bursts, selection preservation and list boundaries.
+The final isolated conversion integration run passed: permanently blocked paste, unexpected editor content, clearing fictional previous results, ignored-first-paste recovery, clipboard restoration, repeat conversion and partial-selection recovery. Typo integration also passed, including Undo and uninterrupted typing. 541 input/UI checks (240 DPI), 105 sync/protocol checks, 483 native regressions and 48 updater checks passed. All release executable versions and manifest hashes were verified. Earlier interactive attempts were interrupted by concurrent input or a transient clipboard-restoration assertion; the final isolated rerun passed.
 
 ## Limitations
-Image decoding or a normalized image larger than the 128 MiB editor-transfer limit can prevent opening; an error is shown. Existing clipboard, OCR and editor privilege limitations remain. The wheel over screenshot annotations changes size/thickness rather than scrolling.
+The cause of every ignored paste is not established. This release does not claim to solve all asynchronous selection failures in ChatGPT/browser editors. Keep Write log enabled and send complete operation details if the issue recurs. Native retry is bounded to one attempt; it is not a general retry policy for other applications. All existing dictionary-correction and synchronization limitations remain.
 
 **Upgrade:** choose Update in the tray menu. Legacy v0.3.0–v0.4.1 clients first receive the v0.4.2 compatibility bridge, then the current full release. v0.2.3 and earlier require manual installation.
 For manual installation, exit KSwitcher, close screenshot editors and extract the entire ZIP into its installation folder. Keep personal `data/` and customized dictionaries.
 
-Download **KSwitcher-win-x64.zip** with **SHA256SUMS.txt**. The package contains all three executables, a release manifest, offline dictionaries, documentation and license notices. It contains no personal settings, clipboard history, development marker, Tesseract installation or language models.
+Download **KSwitcher-win-x64.zip** with **SHA256SUMS.txt**. The package includes all three executables, a release manifest, offline dictionaries, documentation and license notices. No personal settings, passwords, server address or clipboard history are included.
 
 Build and package:
 
@@ -27,4 +26,4 @@ Build and package:
 .\package.ps1 -PublishRelease
 ```
 
-Commit the archive, checksum and sources together. Publish both assets on a stable `release-vX.Y.Z` tag matching the executable version. Keep `v0.4.2` as the last legacy tag.
+Publish stable `release-vX.Y.Z` tags matching the executable version. Keep `v0.4.2` as the last legacy tag.

Release/SHA256SUMS.txt

@@ -1 +1 @@
-0b3c4fd1346d0b4eeb73d276193c5d2789fd32986c3cc75384cf489f23629678  KSwitcher-win-x64.zip
+7e557851ab68a37a8211ea39de41e79314f460ef8ac6471be723d0cfe03cfba9  KSwitcher-win-x64.zip

build.ps1

@@ -15,8 +15,8 @@ Set-Content -LiteralPath (Join-Path (Split-Path $executablePath) '.local-dev') -
 Push-Location $root
 try {
     $common = @('-std=c++20','-Os','-DNDEBUG','-DUNICODE','-D_UNICODE','-DWIN32_LEAN_AND_MEAN','-DNOMINMAX','-D_WIN32_WINNT=0x0A00','-Wall','-Wextra','-Wno-missing-field-initializers','-Isrc','-Ivendor','-ffunction-sections','-fdata-sections')
-    $libs = @('-luser32','-lshell32','-lshlwapi','-ladvapi32','-lcrypt32','-limm32','-lcomctl32','-lgdi32','-lole32','-loleaut32','-ltaskschd','-lcomdlg32','-luuid','-lwindowscodecs','-lruntimeobject','-luiautomationcore')
+    $libs = @('-lwinhttp','-luser32','-lshell32','-lshlwapi','-ladvapi32','-lcrypt32','-limm32','-lcomctl32','-lgdi32','-lole32','-loleaut32','-ltaskschd','-lcomdlg32','-luuid','-lwindowscodecs','-lruntimeobject','-luiautomationcore')
-    foreach ($name in @('core','platform','autostart','autocorrect','storage','ocr','richtext','update','screenshot','screenshot_main','screenshot_notifications','screenshot_activation','screenshot_launcher','app','ui','main','configuration','config_main')) {
+    foreach ($name in @('core','platform','autostart','autocorrect','storage','sync','ocr','richtext','update','screenshot','screenshot_main','screenshot_notifications','screenshot_activation','screenshot_launcher','app','ui','main','configuration','config_main')) {
         & $compiler @common -c "src/$name.cpp" -o "build/$name.o"
         if ($LASTEXITCODE) { throw "Compilation failed: $name" }
     }
@@ -29,11 +29,11 @@ try {
     & windres --codepage=65001 -DKS_SCREENSHOT_RESOURCES resources/app.rc -O coff -o build/screenshot-res.o
     if ($LASTEXITCODE) { throw 'Screenshot resource compilation failed' }
     New-Item -ItemType Directory -Force build/release | Out-Null
-    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/ocr.o build/richtext.o build/update.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui-resident.o build/main.o build/app-res.o @libs -o $executablePath
+    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui-resident.o build/main.o build/app-res.o @libs -o $executablePath
     if ($LASTEXITCODE) { throw 'Link failed' }
     Copy-Item -LiteralPath $executablePath -Destination build/release/KSwitcher.exe -Force
     $configPath = Join-Path (Split-Path $executablePath) 'KSwitcher.Config.exe'
-    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/core.o build/platform.o build/storage.o build/ocr.o build/configuration.o build/config_main.o build/ui-config.o build/app-res.o @libs -o $configPath
+    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/core.o build/platform.o build/storage.o build/sync.o build/ocr.o build/configuration.o build/config_main.o build/ui-config.o build/app-res.o @libs -o $configPath
     if ($LASTEXITCODE) { throw 'Configurator link failed' }
     Copy-Item -LiteralPath $configPath -Destination build/release/KSwitcher.Config.exe -Force
     $screenshotPath = Join-Path (Split-Path $executablePath) 'KSwitcher.Screenshot.exe'
@@ -41,15 +41,19 @@ try {
     if ($LASTEXITCODE) { throw 'Screenshot link failed' }
     Copy-Item -LiteralPath $screenshotPath -Destination build/release/KSwitcher.Screenshot.exe -Force
     if ($Test) {
+        & $compiler @common tests/sync.cpp build/core.o build/platform.o build/storage.o build/sync.o build/ocr.o @libs -static -s -o build/KSwitcherSyncTests.exe
+        if ($LASTEXITCODE) { throw 'Sync test build failed' }
+        & .\build\KSwitcherSyncTests.exe
+        if ($LASTEXITCODE) { throw 'Sync tests failed' }
         & $compiler @common tests/scroll.cpp @libs -static -s -o build/KSwitcherScrollTests.exe
         if ($LASTEXITCODE) { throw 'Scroll test build failed' }
         & .\build\KSwitcherScrollTests.exe
         if ($LASTEXITCODE) { throw 'Scroll tests failed' }
-        & $compiler @common tests/tests.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/ocr.o build/richtext.o build/update.o @libs -static -s -o build/KSwitcherTests.exe
+        & $compiler @common tests/tests.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o @libs -static -s -o build/KSwitcherTests.exe
         if ($LASTEXITCODE) { throw 'Test build failed' }
         & .\build\KSwitcherTests.exe
         if ($LASTEXITCODE) { throw 'Tests failed' }
-        & $compiler @common tests/input.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherInputTests.exe
+        & $compiler @common tests/input.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherInputTests.exe
         if ($LASTEXITCODE) { throw 'Input test build failed' }
         & .\build\KSwitcherInputTests.exe
         if ($LASTEXITCODE) { throw 'Input tests failed' }
@@ -57,6 +61,8 @@ try {
         if ($LASTEXITCODE) { throw 'Screenshot UI test build failed' }
         & .\build\KSwitcherScreenshotUITests.exe
         if ($LASTEXITCODE) { throw 'Screenshot UI tests failed' }
+        & .\build\KSwitcherScreenshotUITests.exe --save-only
+        if ($LASTEXITCODE) { throw 'Screenshot save tests failed' }
         $registrationTest = Join-Path (Split-Path $executablePath) 'KSwitcherRegistrationTests.exe'
         try {
             & $compiler @common tests/screenshot_registration.cpp build/core.o build/platform.o @libs -static '-Wl,--gc-sections' -s -o $registrationTest
@@ -71,13 +77,13 @@ try {
         if ($LASTEXITCODE) { throw 'Updater progress UI tests failed' }
     }
     if ($Integration) {
-        & $compiler @common tests/integration.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherIntegration.exe
+        & $compiler @common tests/integration.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherIntegration.exe
         if ($LASTEXITCODE) { throw 'Integration test build failed' }
         & .\build\KSwitcherIntegration.exe
         if ($LASTEXITCODE) { throw 'Integration tests failed' }
     }
     if ($Ocr) {
-        & $compiler @common tests/ocr.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherOcrTests.exe
+        & $compiler @common tests/ocr.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherOcrTests.exe
         if ($LASTEXITCODE) { throw 'OCR test build failed' }
         & .\build\KSwitcherOcrTests.exe
         if ($LASTEXITCODE) { throw 'OCR tests failed' }

dictionaries/README.md

@@ -17,7 +17,7 @@ replace counts with original frequency ranks, sort lexically. Reproduce with
 hashes. The lists contain word forms from subtitles, not a complete spelling
 or grammar dictionary. Recognition can miss names, jargon and uncommon forms.
 
-Supplemental Ukrainian vocabulary: `реліз`. These additions use rank 50001,
+Supplemental Ukrainian vocabulary: `реліз`, `поточні`. These additions use rank 50001,
 after the upstream 50k list, rather than claiming a measured corpus frequency.
 They are included with the default unlimited rank setting and recorded in sources.json.
 

dictionaries/sources.json

@@ -9,11 +9,12 @@
   "uk": {
     "source": "https://raw.githubusercontent.com/hermitdave/FrequencyWords/525f9b560de45753a5ea01069454e72e9aa541c6/content/2016/uk/uk_50k.txt",
     "sourceSha256": "9548b79a608d33f39c5546037a69117d679730b1fda08dd0ce67c043dbf3335a",
-    "words": 42550,
+    "words": 42551,
-    "bytes": 898227,
+    "bytes": 898248,
-    "sha256": "c94605e6be676d2d64f89a3bc16f92b9128f9977d226a97b103cf22a3e6835e3",
+    "sha256": "caeb097749d4afc84b68ad96b3d7dfb6a6569561cd32ccce0bee94a13b43ba86",
     "supplementalWords": {
-      "\u0440\u0435\u043b\u0456\u0437": 50001
+      "\u0440\u0435\u043b\u0456\u0437": 50001,
+      "\u043f\u043e\u0442\u043e\u0447\u043d\u0456": 50001
     }
   },
   "ru": {

dictionaries/uk.txt

@@ -27337,6 +27337,7 @@
 поторопись	9062
 поторопитесь	20656
 поторопиться	15390
+поточні	50001
 потрапив	4168
 потрапила	7383
 потрапили	6631

resources/app.rc

@@ -9,8 +9,8 @@ IDC_SCREENSHOT_PENCIL CURSOR "icons/lucide/pencil.cur"
 1 RT_MANIFEST "app.manifest"
 201 RCDATA "update.ps1"
 1 VERSIONINFO
- FILEVERSION 0,6,20,0
+ FILEVERSION 0,6,30,0
- PRODUCTVERSION 0,6,20,0
+ PRODUCTVERSION 0,6,30,0
  FILEOS VOS_NT_WINDOWS32
  FILETYPE VFT_APP
 BEGIN
@@ -20,7 +20,7 @@ BEGIN
   BEGIN
    VALUE "FileDescription", "KSwitcher — native keyboard and clipboard utility"
    VALUE "ProductName", "KSwitcher"
-   VALUE "FileVersion", "0.6.20"
+   VALUE "FileVersion", "0.6.30"
   END
  END
  BLOCK "VarFileInfo"

src/app.cpp

@@ -1,4 +1,5 @@
 #include "app.h"
+#include "../vendor/json.hpp"
 #include "../resources/resource.h"
 #include "ocr.h"
 #include "configuration.h"
@@ -11,6 +12,7 @@
 
 namespace ks
 {
+#include "app_sync.inl"
 App *App::current = nullptr;
 namespace
 {
@@ -71,6 +73,8 @@ class Transaction
     Clip snapshot;
     DWORD expected{};
     bool captured{};
+    mutable bool invalidLogged{};
+    unsigned copyNumber{};
     std::wstring adopted;
 
   public:
@@ -106,8 +110,18 @@ class Transaction
     }
     bool valid() const
     {
-        return target && IsWindow(target) && GetForegroundWindow() == target &&
+        auto foreground = GetForegroundWindow();
-               app.inputVersion.load() == version;
+        auto currentVersion = app.inputVersion.load();
+        bool ok = target && IsWindow(target) && foreground == target && currentVersion == version;
+        if (!ok && !invalidLogged)
+        {
+            invalidLogged = true;
+            diagnosticEvent(L"Context invalid: target=" + std::to_wstring((uintptr_t)target) +
+                L" alive=" + std::to_wstring(IsWindow(target)) + L" foreground=" +
+                std::to_wstring((uintptr_t)foreground) + L" expectedVersion=" + std::to_wstring(version) +
+                L" currentVersion=" + std::to_wstring(currentVersion));
+        }
+        return ok;
     }
     void check()
     {
@@ -142,10 +156,14 @@ class Transaction
     }
     std::wstring copy()
     {
+        const auto started = GetTickCount64();
+        const auto number = ++copyNumber;
         if (!valid())
             return {};
         write(textClip(L"\x2063KSwitcher-" + std::to_wstring(GetTickCount64())));
         DWORD before = expected;
+        diagnosticEvent(L"Copy begin number=" + std::to_wstring(number) + L" sentinelSequence=" +
+            std::to_wstring(before) + L" target=" + std::to_wstring((uintptr_t)target));
         if (!valid() || !chord(L'C', MOD_CONTROL))
         {
             diagnosticEvent(L"Copy failed: context changed or simulated Ctrl+C blocked");
@@ -164,6 +182,10 @@ class Transaction
             DWORD now = GetClipboardSequenceNumber();
             if (now != changed)
             {
+                diagnosticEvent(L"Copy sequence number=" + std::to_wstring(number) + L" from=" +
+                    std::to_wstring(changed) + L" to=" + std::to_wstring(now) + L" elapsedMs=" +
+                    std::to_wstring(GetTickCount64() - started) + L" owner=" +
+                    std::to_wstring((uintptr_t)GetClipboardOwner()));
                 changedAgain |= changed != before;
                 changed = now;
                 stable = GetTickCount64();
@@ -181,7 +203,8 @@ class Transaction
                     return {};
                 if (!chord(L'C', MOD_CONTROL))
                     return {};
-                diagnosticEvent(L"Copy retry: clipboard unchanged after Ctrl+C");
+                diagnosticEvent(L"Copy retry: clipboard unchanged after Ctrl+C number=" + std::to_wstring(number) +
+                    L" attempt=" + std::to_wstring(attempts + 1) + L" elapsedMs=" + std::to_wstring(GetTickCount64() - started));
                 ++attempts;
                 retryAt = GetTickCount64() + 250;
             }
@@ -189,6 +212,10 @@ class Transaction
         }
         if (changed == before || !valid())
         {
+            diagnosticEvent(L"Copy end number=" + std::to_wstring(number) + L" attempts=" +
+                std::to_wstring(attempts) + L" elapsedMs=" + std::to_wstring(GetTickCount64() - started) +
+                L" sequence=" + std::to_wstring(GetClipboardSequenceNumber()) + L" clipboardOpenBy=" +
+                std::to_wstring((uintptr_t)GetOpenClipboardWindow()));
             diagnosticEvent(changed == before ? L"Copy failed: clipboard timeout (2000 ms)" :
                                     L"Copy failed: context changed");
             return {};
@@ -199,6 +226,9 @@ class Transaction
         expected = changed;
         auto clip = readClipboard(app.window);
         auto text = clip.text();
+        diagnosticEvent(L"Copy result number=" + std::to_wstring(number) + L" attempts=" +
+            std::to_wstring(attempts) + L" elapsedMs=" + std::to_wstring(GetTickCount64() - started) +
+            L" text=" + diagnosticText(text));
         adopted = text;
         check();
         for (auto &f : clip.formats)
@@ -227,9 +257,31 @@ class Transaction
         return selectPrevious(n, [&] { return valid(); });
     }
     std::wstring copyRange(size_t count, const std::wstring &wordCandidate,
-                           const std::function<bool(const std::wstring &)> &matches)
+                           const std::function<bool(const std::wstring &)> &matches,
+                           const std::function<bool(const std::wstring &)> &suffixMatches = {})
     {
         // WebView word boundaries are only candidates; exact verification is mandatory.
+        diagnosticEvent(L"Selection begin steps=" + std::to_wstring(count) + L" expected=" + diagnosticText(wordCandidate));
+        GUITHREADINFO gui{sizeof(gui)};
+        if (GetGUIThreadInfo(GetWindowThreadProcessId(target, nullptr), &gui))
+        {
+            wchar_t cls[128]{};
+            GetClassNameW(gui.hwndFocus, cls, 128);
+            std::wstring offsets = L"unavailable";
+            if (_wcsicmp(cls, L"Edit") == 0)
+            {
+                DWORD_PTR range{};
+                if (SendMessageTimeoutW(gui.hwndFocus, EM_GETSEL, 0, 0,
+                                       SMTO_ABORTIFHUNG | SMTO_BLOCK, 25, &range) && (DWORD)range != 0xffffffff)
+                    offsets = std::to_wstring(LOWORD(range)) + L"," + std::to_wstring(HIWORD(range));
+            }
+            diagnosticEvent(L"Selection editor class=" + std::wstring(cls) + L" focus=" +
+                std::to_wstring((uintptr_t)gui.hwndFocus) + L" caretWindow=" + std::to_wstring((uintptr_t)gui.hwndCaret) +
+                L" caretRect=" + std::to_wstring(gui.rcCaret.left) + L"," + std::to_wstring(gui.rcCaret.top) +
+                L"," + std::to_wstring(gui.rcCaret.right) + L"," + std::to_wstring(gui.rcCaret.bottom) +
+                L" layout=" + std::to_wstring((uintptr_t)windowLayout(target)) + L" selectionOffsets=" + offsets);
+        }
+        else diagnosticEvent(L"Selection editor: focus/caret/selection unavailable");
         if (needsSelectionDelay(target) && !wordCandidate.empty() &&
             std::all_of(wordCandidate.begin(), wordCandidate.end(),
                         [](wchar_t c) { return letter(c) || iswdigit(c); }))
@@ -238,6 +290,7 @@ class Transaction
                 return {};
             Sleep(25);
             auto text = copy();
+            diagnosticEvent(L"Selection word-boundary match=" + std::to_wstring(matches(text)) + L" copied=" + diagnosticText(text));
             if (valid() && matches(text))
             {
                 diagnosticEvent(L"Selection: verified word boundary");
@@ -247,7 +300,27 @@ class Transaction
                 return {};
             Sleep(25);
         }
-        return select(count) ? copy() : std::wstring{};
+        auto text = select(count) ? copy() : std::wstring{};
+        diagnosticEvent(L"Selection initial match=" + std::to_wstring(matches(text)) + L" copied=" + diagnosticText(text));
+        // Chromium editors can apply only part of a burst of Shift+Left events.
+        // Extend only a verified suffix; never replace a partial or unrelated range.
+        if (valid() && !matches(text) && !text.empty() &&
+            (suffixMatches ? suffixMatches(text) : newlines(wordCandidate).ends_with(newlines(text))) &&
+            caretSteps(text) < count)
+        {
+            const auto missing = count - caretSteps(text);
+            diagnosticEvent(L"Selection: extending verified suffix by " + std::to_wstring(missing));
+            for (size_t i = 0; i < missing; ++i)
+            {
+                if (!valid() || !chord(VK_LEFT, MOD_SHIFT))
+                    return {};
+                diagnosticEvent(L"Selection recovery Shift+Left sent=" + std::to_wstring(i + 1) + L" total=" + std::to_wstring(missing));
+                Sleep(25);
+            }
+            text = copy();
+            diagnosticEvent(L"Selection: suffix recovery match=" + std::to_wstring(matches(text)) + L" copied=" + diagnosticText(text));
+        }
+        return text;
     }
     bool paste(const Clip &clip)
     {
@@ -265,6 +338,32 @@ class Transaction
         Sleep(300);
         return true;
     }
+    bool nativeSelectionIs(const std::wstring &original) const
+    {
+        if (!valid()) return false;
+        GUITHREADINFO gui{sizeof(gui)};
+        if (!GetGUIThreadInfo(GetWindowThreadProcessId(target, nullptr), &gui) || !gui.hwndFocus) return false;
+        wchar_t cls[32]{};
+        GetClassNameW(gui.hwndFocus, cls, 32);
+        if (_wcsicmp(cls, L"Edit") != 0 ||
+            (GetWindowLongPtrW(gui.hwndFocus, GWL_STYLE) & (ES_PASSWORD | ES_READONLY))) return false;
+        auto query = [&](UINT message, WPARAM wp, LPARAM lp, DWORD_PTR &result)
+        {
+            return SendMessageTimeoutW(gui.hwndFocus, message, wp, lp,
+                                       SMTO_ABORTIFHUNG | SMTO_BLOCK, 100, &result) != 0;
+        };
+        DWORD_PTR range{}, length{}, copied{};
+        if (!query(EM_GETSEL, 0, 0, range) || (DWORD)range == 0xffffffff ||
+            size_t(HIWORD(range) - LOWORD(range)) != original.size() ||
+            !query(WM_GETTEXTLENGTH, 0, 0, length) || length > 65534 || HIWORD(range) > length) return false;
+        std::wstring content(length + 1, L'\0');
+        if (!query(WM_GETTEXT, content.size(), (LPARAM)content.data(), copied) || copied != length) return false;
+        DWORD_PTR after{};
+        GUITHREADINFO focused{sizeof(focused)};
+        return query(EM_GETSEL, 0, 0, after) && after == range && valid() &&
+               GetGUIThreadInfo(GetWindowThreadProcessId(target, nullptr), &focused) && focused.hwndFocus == gui.hwndFocus &&
+               content.substr(LOWORD(range), original.size()) == original;
+    }
 };
 } // namespace
 App::App(HINSTANCE h, bool test, const std::filesystem::path &dataRoot) : instance(h), smoke(test)
@@ -303,6 +402,7 @@ App::App(HINSTANCE h, bool test, const std::filesystem::path &dataRoot) : instan
 }
 App::~App()
 {
+    if (syncWorker.joinable()) syncWorker.join();
     if (updateWorker.joinable())
         updateWorker.join();
     if (keyboardHook)
@@ -457,8 +557,16 @@ bool App::registerHotkeys(const Settings &s, bool rollback)
     return true;
 }
 
-void App::applySettings(const Settings &s)
+void App::applySettings(const Settings &requested)
 {
+    Settings s = requested;
+    std::set<std::wstring> present, removed(s.snippetTombstones.begin(), s.snippetTombstones.end());
+    removed.insert(settings.snippetTombstones.begin(), settings.snippetTombstones.end());
+    for (auto &snippet : s.snippets) { snippet.id = snippetId(snippet); present.insert(snippet.id); }
+    for (const auto &snippet : settings.snippets)
+        if (!present.contains(snippetId(snippet))) removed.insert(snippetId(snippet));
+    for (const auto &id : present) removed.erase(id);
+    s.snippetTombstones.assign(removed.begin(), removed.end());
     bool autostartChanged = false;
     AutoCorrector predictor;
     validateSettings(s);
@@ -502,10 +610,12 @@ void App::applySettings(const Settings &s)
         run.reset();
         last.reset();
         ++inputVersion;
+        if (busy) diagnosticEvent(L"Input context changed: settings applied version=" + std::to_wstring(inputVersion.load()));
     }
     // Clear on the worker so the next check reloads edits to dictionary files.
     enqueue([this] { autoCorrector.configure({}, {}); });
     scheduleHistoryOcr(s);
+    nextSync = std::max(GetTickCount64() + 2000, syncRetryAfter);
     SetThreadExecutionState(ES_CONTINUOUS |
                             (settings.awake ? (ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED) : 0));
 }
@@ -529,6 +639,7 @@ void App::reloadLayouts()
         run.reset();
         last.reset();
         ++inputVersion;
+        if (busy) diagnosticEvent(L"Input context changed: layouts reloaded version=" + std::to_wstring(inputVersion.load()));
     }
     registerHotkeys(settings);
 }
@@ -558,6 +669,7 @@ void App::resetInput()
 {
     std::lock_guard lock(stateMutex);
     ++inputVersion;
+    if (busy) diagnosticEvent(L"Input context changed: reset version=" + std::to_wstring(inputVersion.load()));
     run.reset();
     last.reset();
 }
@@ -575,6 +687,9 @@ void App::keyboard(const KBDLLHOOKSTRUCT &k, UINT mods)
     if (isHotkey(vk, mods))
         return;
     ++inputVersion;
+    if (busy) diagnosticEvent(L"Input context changed: keyboard vk=" + std::to_wstring(vk) +
+        L" modifiers=" + std::to_wstring(mods) + L" injected=" + std::to_wstring((k.flags & LLKHF_INJECTED) != 0) +
+        L" version=" + std::to_wstring(inputVersion.load()));
     last.reset();
     HWND fg = GetForegroundWindow();
     HKL layout = windowLayout(fg);
@@ -808,7 +923,10 @@ LRESULT CALLBACK App::mouseProc(int code, WPARAM wp, LPARAM lp)
         // KSwitcher generates no mouse input. Remote clicks invalidate a typing
         // range just like local clicks, including while a transaction is pending.
         if (wp == WM_LBUTTONDOWN || wp == WM_RBUTTONDOWN || wp == WM_MBUTTONDOWN || wp == WM_MOUSEWHEEL)
+        {
+            if (current->busy) diagnosticEvent(L"Input context changed: mouse message=" + std::to_wstring(wp));
             current->resetInput();
+        }
     }
     return CallNextHookEx(nullptr, code, wp, lp);
 }
@@ -979,9 +1097,10 @@ void App::transform(int command, int snippet)
                                     !(command == 0 && reason == L"paste-sent-unverified")},
                                 {"elapsedMs", GetTickCount64() - start}, {"foregroundSame", GetForegroundWindow() == target},
                                 {"inputSame", app.inputVersion.load() == version}, {"original", bounded(text)},
-                                {"expected", bounded(result)}, {"actual", bounded(actual)},
+                                {"expected", bounded(verification == L"selection-mismatch" ? expected : result)}, {"actual", bounded(actual)},
-                                {"originalUnits", text.size()}, {"expectedUnits", result.size()}, {"actualUnits", actual.size()},
+                                {"selectionExpected", bounded(expected)},
-                                {"textTruncated", text.size() > 4096 || result.size() > 4096 || actual.size() > 4096}};
+                                {"originalUnits", text.size()}, {"expectedUnits", (verification == L"selection-mismatch" ? expected : result).size()}, {"actualUnits", actual.size()},
+                                {"textTruncated", text.size() > 4096 || result.size() > 4096 || actual.size() > 4096 || expected.size() > 4096}};
                             diagnosticOperation(record.dump(-1, ' ', true, DiagnosticJson::error_handler_t::replace));
                         }
                         catch (...) {} // Logging must never abort a completed input transaction.
@@ -1104,6 +1223,8 @@ void App::transform(int command, int snippet)
                     if (newlines(text) != newlines(previous->result))
                     {
                         reason = L"undo-verification-mismatch";
+                        actual = text;
+                        verification = L"selection-mismatch";
                         if (tx.valid())
                             chord(VK_RIGHT);
                         return;
@@ -1138,12 +1259,16 @@ void App::transform(int command, int snippet)
                 {
                     text =
                         tx.copyRange(recent.keys.size(), recent.keys, [&](const std::wstring &candidate)
-                                     { return recent.match(candidate, available, physicalLayout()) >= 0; });
+                                     { return recent.match(candidate, available, physicalLayout()) >= 0; },
+                                     [&](const std::wstring &candidate)
+                                     { return recent.matchSuffix(candidate, available, physicalLayout()) >= 0; });
                     hint = recent.match(text, available, physicalLayout());
                     diagnosticEvent(L"Recent verification copied=" + std::to_wstring(text.size()) + L" keys=" +
                         std::to_wstring(recent.keys.size()) + L" match=" + std::to_wstring(hint));
                     if (hint < 0)
                     {
+                        actual = text;
+                        verification = L"selection-mismatch";
                         reason = text.empty() ? L"recent-copy-empty" : L"recent-verification-mismatch";
                         if (tx.valid())
                             chord(VK_RIGHT);
@@ -1155,12 +1280,20 @@ void App::transform(int command, int snippet)
                          previous->version == version)
                 {
                     expected = previous->result;
+                    diagnosticEvent(L"Previous result expected=" + diagnosticText(expected));
                     text = tx.copyRange(caretSteps(previous->result), previous->result,
                                         [&](const std::wstring &candidate)
                                         { return newlines(candidate) == newlines(previous->result); });
                     if (newlines(text) != newlines(previous->result))
                     {
+                        actual = text;
+                        verification = L"selection-mismatch";
                         reason = L"previous-result-verification-mismatch";
+                        {
+                            std::lock_guard lock(stateMutex);
+                            last.reset();
+                            run.reset();
+                        }
                         if (tx.valid())
                             chord(VK_RIGHT);
                         return;
@@ -1202,11 +1335,7 @@ void App::transform(int command, int snippet)
                                     chord(VK_RIGHT);
                                 return;
                             }
-                            int source = detect(text, available, hint);
+                            to = nextConversionLayout(text, available, cycle, hint);
-                            if (source < 0)
-                                source = hint;
-                            auto it = std::find(cycle.begin(), cycle.end(), source);
-                            to = it == cycle.end() || ++it == cycle.end() ? cycle.front() : *it;
                         }
                         result = convertTo(text, available, to, hint);
                     }
@@ -1234,11 +1363,30 @@ void App::transform(int command, int snippet)
                     if (tx.valid())
                     {
                         auto observed = probe.read((int)caretSteps(result));
+                        // A native Edit may silently ignore Ctrl+V while the clipboard is busy.
+                        // Retry once only with fresh native proof that the exact original range
+                        // is still selected. Never retry an unknown or changed editor state.
+                        if (observed && newlines(*observed) == newlines(text) && tx.nativeSelectionIs(text))
+                        {
+                            diagnosticEvent(L"Paste retry: native Edit still selects the unchanged original");
+                            if (tx.paste(textClip(result)) && tx.valid())
+                                observed = probe.read((int)caretSteps(result));
+                            else
+                                observed.reset();
+                        }
                         verification = probe.status;
                         if (observed && tx.valid())
                         {
                             actual = *observed;
                             reason = conversionReadbackOutcome(newlines(actual), newlines(text), newlines(result));
+                            if (newlines(actual) != newlines(result))
+                            {
+                                std::lock_guard lock(stateMutex);
+                                last.reset();
+                                run.reset();
+                                diagnosticEvent(L"Paste rejected by readback: previous result cleared; layout not switched");
+                                return;
+                            }
                         }
                         else reason = L"Paste not verified";
                     }
@@ -1423,28 +1571,28 @@ void App::recognizeEntry(std::wstring id)
 void App::trayMenu()
 {
     HMENU menu = CreatePopupMenu();
-    AppendMenuW(menu, MF_STRING, 10, L"Clipboard history");
+    AppendMenuW(menu, MF_STRING, 10, L"Clipboard &history");
-    AppendMenuW(menu, MF_STRING, 24, L"Capture screen region…");
+    AppendMenuW(menu, MF_STRING, 24, L"&Capture screen region…");
-    AppendMenuW(menu, MF_STRING, 11, L"Settings…");
+    AppendMenuW(menu, MF_STRING, 11, L"&Settings…");
     SetMenuDefaultItem(menu, 11, FALSE);
-    AppendMenuW(menu, MF_STRING, 12, L"Snippets…");
+    AppendMenuW(menu, MF_STRING, 12, L"S&nippets…");
-    AppendMenuW(menu, MF_STRING, 13, L"Keyboard shortcuts…");
+    AppendMenuW(menu, MF_STRING, 13, L"&Keyboard shortcuts…");
     AppendMenuW(menu, MF_SEPARATOR, 0, nullptr);
-    AppendMenuW(menu, MF_STRING | (settings.awake ? MF_CHECKED : 0), 14, L"Keep screen awake");
+    AppendMenuW(menu, MF_STRING | (settings.awake ? MF_CHECKED : 0), 14, L"Keep screen a&wake");
     HMENU pause = CreatePopupMenu();
-    AppendMenuW(pause, MF_STRING, 20, L"Resume");
+    AppendMenuW(pause, MF_STRING, 20, L"&Resume");
-    AppendMenuW(pause, MF_STRING, 21, L"10 minutes");
+    AppendMenuW(pause, MF_STRING, 21, L"&10 minutes");
-    AppendMenuW(pause, MF_STRING, 22, L"1 hour");
+    AppendMenuW(pause, MF_STRING, 22, L"1 &hour");
-    AppendMenuW(pause, MF_STRING, 23, L"Until restart");
+    AppendMenuW(pause, MF_STRING, 23, L"&Until restart");
-    AppendMenuW(menu, MF_POPUP, (UINT_PTR)pause, L"Pause clipboard history");
+    AppendMenuW(menu, MF_POPUP, (UINT_PTR)pause, L"&Pause clipboard history");
-    AppendMenuW(menu, MF_STRING, 15, L"Open data folder");
+    AppendMenuW(menu, MF_STRING, 15, L"&Open data folder");
-    AppendMenuW(menu, MF_STRING, 18, L"View log…");
+    AppendMenuW(menu, MF_STRING, 18, L"View &log…");
     AppendMenuW(menu, MF_STRING | (updateRunning ? MF_GRAYED : 0), 19,
-                updateRunning ? L"Update (checking / preparing…)" :
+                updateRunning ? L"&Update (checking / preparing…)" :
-                availableUpdate.empty() ? L"Update" : L"Update (new version available)");
+                availableUpdate.empty() ? L"&Update" : L"&Update (new version available)");
     AppendMenuW(menu, MF_SEPARATOR, 0, nullptr);
-    AppendMenuW(menu, MF_STRING, 16, L"About KSwitcher");
+    AppendMenuW(menu, MF_STRING, 16, L"&About KSwitcher");
-    AppendMenuW(menu, MF_STRING, 17, L"Exit");
+    AppendMenuW(menu, MF_STRING, 17, L"E&xit");
     POINT pt;
     GetCursorPos(&pt);
     pasteTarget = GetForegroundWindow();
@@ -1675,6 +1823,11 @@ LRESULT CALLBACK App::windowProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
         return TRUE;
     }
     case WM_TIMER:
+        if (wp == 6)
+        {
+            app->pollSync();
+            return 0;
+        }
         if (wp == 5)
         {
             // After the initial 5-second check, repeat while the resident stays open.
@@ -1777,6 +1930,7 @@ int App::execute()
     scheduleHistoryOcr(settings);
     addTray();
     SetTimer(window, 1, 60000, nullptr);
+    if (!smoke) SetTimer(window, 6, 1000, nullptr);
     SetThreadExecutionState(ES_CONTINUOUS |
                             (settings.awake ? (ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED) : 0));
     if (!registrationWarning.empty())
@@ -1801,6 +1955,9 @@ int App::execute()
             if (popup != settingsWindow && IsDialogMessageW(popup, &msg))
                 continue;
         }
+        // Preserve history-specific Enter/Shift+Enter and Ctrl+digit handling.
+        if (historyWindow && msg.message == WM_SYSCHAR && IsDialogMessageW(historyWindow, &msg))
+            continue;
         if (settingsWindow && IsDialogMessageW(settingsWindow, &msg))
             continue;
         if (snippetsWindow && IsDialogMessageW(snippetsWindow, &msg))

src/app.h

@@ -2,6 +2,7 @@
 #include "autocorrect.h"
 #include "storage.h"
 #include "update.h"
+#include "sync.h"
 #include <atomic>
 #include <condition_variable>
 #include <deque>
@@ -78,6 +79,9 @@ class App
     bool handleKeyboard(const KBDLLHOOKSTRUCT &, bool down, UINT modifiers);
     void resetInput();
     void checkUpdate(bool interactive, bool install = false, const std::wstring &version = {});
+    std::wstring syncCommand(int action = 0, const std::vector<SyncChoice> &choices = {});
+    Bytes syncConflictData();
+    void pollSync();
     static App *current;
 
   private:
@@ -96,6 +100,16 @@ class App
     Settings historyOcrSettings;
     void scheduleHistoryOcr(const Settings &);
     std::thread updateWorker;
+    std::thread syncWorker;
+    std::atomic<bool> syncDone{false};
+    bool syncRunning{};
+    ULONGLONG nextSync{}, syncRetryAfter{};
+    SyncResult syncResult;
+    SyncConfig syncConnection;
+    SyncConfig conflictConnection;
+    std::vector<SyncConflict> pendingSyncConflicts;
+    Bytes syncSnapshot;
+    std::wstring syncStatus = L"Not connected.";
     bool updateRunning{}, installingUpdate{};
     std::wstring availableUpdate, notifiedUpdate;
     bool (*updateNotifier)(const std::wstring &){};

src/app_sync.inl

@@ -0,0 +1,98 @@
+// Included by app.cpp; all App mutations happen on its window thread.
+Bytes App::syncConflictData()
+{
+    if (loadSyncConfig(data) != conflictConnection) return encodeSyncConflicts({});
+    return encodeSyncConflicts(pendingSyncConflicts);
+}
+std::wstring App::syncCommand(int action, const std::vector<SyncChoice> &choices)
+{
+    if (action == 0) return syncStatus;
+    if (syncRunning) return L"Synchronization is already running.";
+    auto c = loadSyncConfig(data);
+    if (!c.enabled) return syncStatus = L"Synchronization is disabled.";
+    validateSyncConfig(c);
+    if (action == 4 && (c != conflictConnection || choices.empty()))
+        throw std::runtime_error("Connection changed or no choices selected. Sync again.");
+    if (busy) return L"Wait for the current text operation to finish.";
+    syncRetryAfter = 0; // Explicit retries may bypass the automatic error backoff.
+    if (syncWorker.joinable()) syncWorker.join();
+    syncConnection = c;
+    syncSnapshot = encodeSettings(settings);
+    auto snapshot = settings;
+    auto availableLayouts = layouts;
+    syncRunning = true;
+    syncDone = false;
+    syncStatus = L"Connecting to OpenBao...";
+    nextSync = GetTickCount64() + SyncIntervalMs;
+    try
+    {
+        syncWorker = std::thread([this, c, snapshot, availableLayouts, action, choices] {
+            SyncResult result;
+            try
+            {
+                auto provider = makeSyncProvider(c);
+                // An explicit choice also repairs a missing/corrupt local baseline.
+                auto base = action == 1 || action == 4 ? loadSyncBase(data, c) : Bytes{};
+                result = synchronize(*provider, base, sharedSyncSettings(snapshot),
+                    action == 2 ? SyncAction::Download : action == 3 ? SyncAction::Upload : SyncAction::Automatic,
+                    [&](const Bytes &b) { restoreSyncSettings(b, snapshot, availableLayouts, c.keepLocalLayouts); }, choices,
+                    c.keepLocalLayouts);
+                if (result.success && c.keepLocalLayouts)
+                    result.status += L" Partial sync: this PC's layouts and their shortcuts were kept; server layouts were preserved.";
+            }
+            catch (const nlohmann::json::exception &) { result.status = L"Invalid sync data or server response."; }
+            catch (const std::exception &e) { result.status = wide(e.what()); }
+            syncResult = std::move(result);
+            syncDone.store(true);
+        });
+    }
+    catch (...) { syncRunning = false; throw; }
+    return syncStatus;
+}
+void App::pollSync()
+{
+    try
+    {
+        if (syncRunning && syncDone.load())
+        {
+            if (busy) return;
+            syncWorker.join();
+            syncRunning = false;
+            syncDone = false;
+            syncStatus = syncResult.status;
+            if (syncResult.success)
+            {
+                if (loadSyncConfig(data) != syncConnection || encodeSettings(settings) != syncSnapshot)
+                {
+                    syncStatus = L"Local settings or connection changed during sync. Checking again shortly.";
+                    nextSync = GetTickCount64() + 2000;
+                    return;
+                }
+                auto next = restoreSyncSettings(syncResult.settings, settings, layouts, syncConnection.keepLocalLayouts);
+                if (encodeSettings(next) != syncSnapshot)
+                {
+                    atomicWrite(data / L"settings-before-sync.bin", protect(syncSnapshot));
+                    applySettings(next);
+                }
+                saveSyncBase(data, syncConnection, syncResult.base.empty() ? syncResult.settings : syncResult.base);
+                pendingSyncConflicts = syncResult.conflicts;
+                conflictConnection = syncConnection;
+                SYSTEMTIME time{}; GetLocalTime(&time);
+                wchar_t stamp[32]{};
+                swprintf(stamp, std::size(stamp), L" (%02u:%02u:%02u)", time.wHour, time.wMinute, time.wSecond);
+                syncStatus += stamp;
+            }
+            // Back off after errors (including bad credentials) instead of repeatedly
+            // hitting userpass lockout. The explicit Sync button remains available.
+            syncRetryAfter = syncResult.success ? 0 : GetTickCount64() + 15 * 60000;
+            nextSync = syncResult.success ? GetTickCount64() + SyncIntervalMs : syncRetryAfter;
+        }
+        if (!syncRunning && GetTickCount64() >= nextSync)
+        {
+            nextSync = GetTickCount64() + SyncIntervalMs;
+            if (loadSyncConfig(data).enabled) syncCommand(1);
+        }
+    }
+    catch (const nlohmann::json::exception &) { syncStatus = L"Invalid local sync configuration or cached profile."; nextSync = GetTickCount64() + SyncIntervalMs; }
+    catch (const std::exception &e) { syncStatus = wide(e.what()); nextSync = GetTickCount64() + SyncIntervalMs; }
+}

src/autocorrect.cpp

@@ -164,6 +164,24 @@ std::optional<AutoSuggestion> AutoCorrector::suggest(const std::wstring &typed,
     auto sourceLanguage = layoutLanguage(layouts[source]);
     if (!dictionaries.contains(sourceLanguage))
         return {};
+    const std::wstring alphabet = sourceLanguage == L"en" ? L"abcdefghijklmnopqrstuvwxyz" :
+        sourceLanguage == L"uk" ? L"абвгґдеєжзиіїйклмнопрстуфхцчшщьюя" : L"абвгдеёжзийклмнопрстуфхцчшщъыьэюя";
+    auto small = lower(word);
+    bool sameLanguage = safeAutoWord(word, settings.autoMinLength) &&
+        small.find_first_not_of(alphabet) == small.npos &&
+        std::find(settings.cycle.begin(), settings.cycle.end(), layouts[source].id) != settings.cycle.end();
+    auto sameLayout = [&](std::wstring text)
+    {
+        if (word != small) text[0] = upper(text.substr(0, 1))[0];
+        return AutoSuggestion{source, source, prefix + text + suffix};
+    };
+    if (settings.autoReplace && sameLanguage)
+    {
+        auto replacement = settings.autoReplacements.find(small);
+        if (replacement != settings.autoReplacements.end() &&
+            replacement->second.find_first_not_of(alphabet) == small.npos)
+            return sameLayout(replacement->second);
+    }
     auto personal = [&](const std::wstring &language, const std::wstring &candidate)
     {
         auto found = settings.autoWords.find(language);
@@ -203,7 +221,54 @@ std::optional<AutoSuggestion> AutoCorrector::suggest(const std::wstring &typed,
             (!candidate || priority(i) < priority(candidate->target)))
             candidate = AutoSuggestion{source, i, prefix + converted + suffix};
     }
-    return candidate;
+    if (candidate || matchedText || !settings.autoTypos || !sameLanguage || word.size() < 4)
+        return candidate;
+    // Generate only single edits. Stop at a second distinct dictionary hit,
+    // including rare hits: frequency limits must never hide ambiguity.
+    std::wstring found;
+    int foundRank = 0;
+    std::set<std::wstring> personalTargets;
+    if (auto it = settings.autoWords.find(sourceLanguage); it != settings.autoWords.end())
+        for (const auto &text : it->second) personalTargets.insert(lower(text));
+    auto consider = [&](const std::wstring &text)
+    {
+        if (text == small || text == found || text.size() < 4 || text.size() > 32) return true;
+        int rank = personalTargets.contains(text) ? 1 : dictionaries.at(sourceLanguage).rank(text);
+        if (!rank) return true;
+        if (!found.empty()) return false;
+        found = text;
+        foundRank = rank;
+        return true;
+    };
+    for (size_t i = 0; i < small.size(); ++i)
+    {
+        auto text = small;
+        text.erase(i, 1);
+        if (!consider(text)) return {};
+        if (i + 1 < small.size())
+        {
+            text = small;
+            std::swap(text[i], text[i + 1]);
+            if (!consider(text)) return {};
+        }
+        for (wchar_t c : alphabet)
+        {
+            text = small;
+            text[i] = c;
+            if (!consider(text)) return {};
+        }
+    }
+    if (small.size() < 32)
+        for (size_t i = 0; i <= small.size(); ++i)
+            for (wchar_t c : alphabet)
+            {
+                auto text = small;
+                text.insert(i, 1, c);
+                if (!consider(text)) return {};
+            }
+    if (!found.empty() && (settings.autoMaxRank == 0 || foundRank <= settings.autoMaxRank))
+        return sameLayout(found);
+    return {};
 }
 int matchAutoInput(const Run &run, const std::wstring &text, const std::vector<Layout> &layouts,
                    const Layout &physical, const Settings &settings)

src/config_main.cpp

@@ -82,6 +82,7 @@ LRESULT CALLBACK controller(HWND window, UINT message, WPARAM wp, LPARAM lp)
 App::App(HINSTANCE h, bool, const std::filesystem::path &) : instance(h)
 {
     current = this;
+    data = dataDirectory();
     layouts = readLayouts();
 }
 App::~App()
@@ -110,6 +111,13 @@ void App::reloadLayouts()
     settings = decodeSettings(bytes, layouts);
 }
 void App::clearHistory() { request(*this, ConfigClearHistory); }
+Bytes App::syncConflictData() { return request(*this, ConfigSyncConflicts); }
+std::wstring App::syncCommand(int action, const std::vector<SyncChoice> &choices)
+{
+    auto result = action == 4 ? request(*this, ConfigSyncResolve, encodeSyncChoices(choices)) :
+        request(*this, ConfigSync, Bytes{static_cast<unsigned char>(action)});
+    return wide(std::string(result.begin(), result.end()));
+}
 void App::setHotkeyCapture(HWND field)
 {
     hotkeyCapture = field;
@@ -180,6 +188,12 @@ int runConfigurator(HINSTANCE instance, bool snippets, bool logs)
         if (app.settingsWindow && !IsWindowEnabled(app.settingsWindow))
         {
             HWND popup = GetLastActivePopup(app.settingsWindow);
+            while (!IsWindowEnabled(popup))
+            {
+                HWND next = GetLastActivePopup(popup);
+                if (next == popup) break;
+                popup = next;
+            }
             if (popup != app.settingsWindow && IsDialogMessageW(popup, &message)) continue;
         }
         if (app.settingsWindow && IsDialogMessageW(app.settingsWindow, &message)) continue;

src/configuration.cpp

@@ -40,6 +40,25 @@ LRESULT configurationRequest(App &app, HWND sender, const COPYDATASTRUCT &messag
     {
         switch (message.dwData)
         {
+        case ConfigSyncConflicts:
+            reply = app.syncConflictData();
+            break;
+        case ConfigSyncResolve:
+        {
+            if (!message.cbData) throw std::runtime_error("Empty conflict choices.");
+            auto first = static_cast<const unsigned char *>(message.lpData);
+            auto status = utf8(app.syncCommand(4, decodeSyncChoices(Bytes(first, first + message.cbData))));
+            reply.assign(status.begin(), status.end());
+            break;
+        }
+        case ConfigSync:
+        {
+            if (message.cbData != 1 || *static_cast<const unsigned char *>(message.lpData) > 3)
+                throw std::runtime_error("Invalid sync command.");
+            auto status = utf8(app.syncCommand(*static_cast<const unsigned char *>(message.lpData)));
+            reply.assign(status.begin(), status.end());
+            break;
+        }
         case ConfigSave:
         {
             if (app.busy) throw std::runtime_error("Wait for the current text operation to finish.");

src/configuration.h

@@ -5,7 +5,9 @@ namespace ks
 inline constexpr ULONG_PTR ConfigRead = 0x4b530100, ConfigSave = ConfigRead + 1,
     ConfigLayouts = ConfigRead + 2, ConfigClearHistory = ConfigRead + 3,
     ConfigCapture = ConfigRead + 4, ConfigLogs = ConfigRead + 5,
-    ConfigReply = ConfigRead + 6, ConfigClearLog = ConfigRead + 7, ConfigEnd = ConfigRead + 8;
+    ConfigReply = ConfigRead + 6, ConfigClearLog = ConfigRead + 7,
+    ConfigSync = ConfigRead + 8, ConfigSyncConflicts = ConfigRead + 9,
+    ConfigSyncResolve = ConfigRead + 10, ConfigEnd = ConfigRead + 11;
 inline constexpr size_t ConfigLimit = 8 * 1024 * 1024;
 bool configurationPeer(HWND, const wchar_t *filename);
 void launchConfiguration(App &, bool snippets = false, bool logs = false);

src/core.cpp

@@ -148,6 +148,26 @@ std::wstring convertTo(const std::wstring &text, const std::vector<Layout> &layo
     }
     return best < 0 ? text : convert(text, layouts[best], to);
 }
+int nextConversionLayout(const std::wstring &text, const std::vector<Layout> &layouts,
+                         const std::vector<int> &cycle, int hint)
+{
+    if (cycle.empty())
+        return -1;
+    int source = detect(text, layouts, hint);
+    if (source < 0)
+        source = hint;
+    auto it = std::find(cycle.begin(), cycle.end(), source);
+    size_t start = it == cycle.end() ? 0 : (size_t(it - cycle.begin()) + 1) % cycle.size();
+    // Compare every candidate with the original input, never an intermediate conversion.
+    // Bound the search so digits, whitespace and identical layouts cannot loop forever.
+    for (size_t offset = 0; offset < cycle.size(); ++offset)
+    {
+        int target = cycle[(start + offset) % cycle.size()];
+        if (target != source && convertTo(text, layouts, target, hint) != text)
+            return target;
+    }
+    return cycle[start];
+}
 std::wstring cycleCase(const std::wstring &text)
 {
     if (text == upper(text))
@@ -459,6 +479,14 @@ void Run::backspace(HWND w, ULONGLONG now)
         keys.pop_back();
     at = now;
 }
+int Run::matchSuffix(const std::wstring &text, const std::vector<Layout> &layouts, const Layout &physical) const
+{
+    if (text.empty() || text.size() >= keys.size() || overflow)
+        return -1;
+    Run tail = *this;
+    tail.keys = keys.substr(keys.size() - text.size());
+    return tail.match(text, layouts, physical);
+}
 int Run::match(const std::wstring &text, const std::vector<Layout> &layouts, const Layout &physical) const
 {
     if (text.size() != keys.size() || overflow)

src/core.h

@@ -24,12 +24,17 @@ std::wstring upper(std::wstring text);
 std::wstring convert(const std::wstring &, const Layout &, const Layout &, bool force = false);
 int detect(const std::wstring &, const std::vector<Layout> &, int preferred = -1);
 std::wstring convertTo(const std::wstring &, const std::vector<Layout> &, int target, int hint);
+int nextConversionLayout(const std::wstring &, const std::vector<Layout> &,
+                         const std::vector<int> &cycle, int hint);
 std::wstring cycleCase(const std::wstring &);
 std::wstring transliterate(const std::wstring &);
 struct Snippet
 {
     std::wstring trigger, text;
+    std::wstring id;
 };
+std::wstring snippetId(const Snippet &);
+std::wstring newSnippetId();
 struct Template
 {
     std::wstring text, suffix;
@@ -49,6 +54,8 @@ struct Settings
     bool recent = true, switchLayout = true, history = true, autostart = false, awake = false;
     bool elevatedAutostart = false;
     bool autoCorrect = false;
+    bool autoReplace = false, autoTypos = false;
+    std::map<std::wstring, std::wstring> autoReplacements;
     bool writeLog = true;
     bool screenshotAutoOpenEditor = false;
     bool useTesseract = false;
@@ -71,6 +78,7 @@ struct Settings
     std::vector<std::wstring> cycle, direct, directIds;
     std::vector<std::wstring> excluded{L"KeePass", L"KeePassXC", L"1Password", L"Bitwarden"};
     std::vector<Snippet> snippets;
+    std::vector<std::wstring> snippetTombstones;
 };
 // Consume repeats and key-up for intercepted chords, even if settings change.
 struct HotkeyHook
@@ -92,5 +100,6 @@ struct Run
     void record(wchar_t, HWND, HKL, ULONGLONG);
     void backspace(HWND, ULONGLONG);
     int match(const std::wstring &, const std::vector<Layout> &, const Layout &physical) const;
+    int matchSuffix(const std::wstring &, const std::vector<Layout> &, const Layout &physical) const;
 };
 } // namespace ks

src/diagnostics.h

@@ -37,7 +37,8 @@ inline std::vector<OperationLogRow> parseOperationLog(const std::wstring &conten
                     L"Operation: " + field("attempt") + L"\r\nResult: " + row.outcome +
                     L"\r\nVerification: " + field("verification") + L"\r\nElapsed: " +
                     std::to_wstring(j.value("elapsedMs", 0ULL)) + L" ms\r\n\r\nOriginal:\r\n" +
-                    field("original") + L"\r\n\r\nExpected result:\r\n" + field("expected") +
+                    field("original") + L"\r\n\r\nExpected selection:\r\n" + field("selectionExpected") +
+                    L"\r\n\r\nExpected result / verification target:\r\n" + field("expected") +
                     L"\r\n\r\nRead back:\r\n" + field("actual") + L"\r\n\r\nForeground unchanged: " +
                     (j.value("foregroundSame", false) ? L"yes" : L"no") + L"\r\nInput context unchanged: " +
                     (j.value("inputSame", false) ? L"yes" : L"no") + L"\r\nText truncated: " +

src/ocr.cpp

@@ -186,6 +186,43 @@ Pixels decodeImage(const Clip &clip, UINT maxWidth, UINT maxHeight)
     check(converter->CopyPixels(nullptr, pixels.width * 4, (UINT)pixels.bgra.size(), pixels.bgra.data()));
     return pixels;
 }
+Bytes encodePng(const Pixels &p)
+{
+    if (!p.width || !p.height || uint64_t(p.width) * p.height * 4 != p.bgra.size() ||
+        p.bgra.size() > UINT_MAX || p.width > UINT_MAX / 4)
+        throw std::runtime_error("Invalid PNG image dimensions");
+    Com<IWICImagingFactory> factory;
+    check(CoCreateInstance(CLSID_WICImagingFactory, nullptr, CLSCTX_INPROC_SERVER,
+                           IID_PPV_ARGS(factory.out())));
+    Com<IStream> stream;
+    check(CreateStreamOnHGlobal(nullptr, TRUE, stream.out()));
+    Com<IWICBitmapEncoder> encoder;
+    check(factory->CreateEncoder(GUID_ContainerFormatPng, nullptr, encoder.out()));
+    check(encoder->Initialize(stream.p, WICBitmapEncoderNoCache));
+    Com<IWICBitmapFrameEncode> frame;
+    check(encoder->CreateNewFrame(frame.out(), nullptr));
+    check(frame->Initialize(nullptr));
+    check(frame->SetSize(p.width, p.height));
+    auto format = GUID_WICPixelFormat32bppBGRA;
+    check(frame->SetPixelFormat(&format));
+    if (format != GUID_WICPixelFormat32bppBGRA)
+        throw std::runtime_error("Unsupported PNG pixel format");
+    check(frame->WritePixels(p.height, p.width * 4, (UINT)p.bgra.size(),
+                             const_cast<BYTE *>(p.bgra.data())));
+    check(frame->Commit());
+    check(encoder->Commit());
+    STATSTG stat{};
+    check(stream->Stat(&stat, STATFLAG_NONAME));
+    if (stat.cbSize.QuadPart > UINT_MAX)
+        throw std::runtime_error("PNG image is too large");
+    check(stream->Seek({}, STREAM_SEEK_SET, nullptr));
+    Bytes bytes((size_t)stat.cbSize.QuadPart);
+    ULONG read{};
+    check(stream->Read(bytes.data(), (ULONG)bytes.size(), &read));
+    if (read != bytes.size())
+        throw std::runtime_error("Cannot read encoded PNG image");
+    return bytes;
+}
 Format imageDib(const Pixels &p)
 {
     BITMAPINFOHEADER h{};

src/ocr.h

@@ -9,6 +9,7 @@ struct Pixels
 };
 Pixels decodeImage(const Clip &, UINT maxWidth = 0, UINT maxHeight = 0);
 Format imageDib(const Pixels &);
+Bytes encodePng(const Pixels &);
 std::wstring recognizeText(const Clip &);
 std::wstring recognizeText(const Clip &, const Settings &);
 std::filesystem::path tesseractExecutable(const Settings &);

src/platform.cpp

@@ -396,22 +396,27 @@ bool chord(WORD key, UINT mods)
 bool needsSelectionDelay(HWND target)
 {
     const auto name = lower(processName(target));
-    return name == L"ms-teams" || name == L"msedgewebview2";
+    return name == L"ms-teams" || name == L"msedgewebview2" ||
+           name == L"chrome" || name == L"msedge";
 }
 bool selectPrevious(size_t count, const std::function<bool()> &valid)
 {
     if (count > 100000)
         return false;
-    // Teams' WebView editor applies selection changes asynchronously. A burst of
+    // Chromium and Teams' WebView editors apply selection changes asynchronously. A burst of
     // Shift+Left events can all use the same caret position and select only one
     // character. Give each change time to settle before sending the next one.
     const auto target = GetForegroundWindow();
+    diagnosticEvent(L"SelectPrevious requested=" + std::to_wstring(count) +
+        L" mode=" + (needsSelectionDelay(target) ? std::wstring(L"paced-25ms") : std::wstring(L"batch")));
     if (needsSelectionDelay(target))
     {
         for (size_t i = 0; i < count; ++i)
         {
             if (!valid() || GetForegroundWindow() != target || !chord(VK_LEFT, MOD_SHIFT))
                 return false;
+            if (i < 32 || i + 1 == count)
+                diagnosticEvent(L"SelectPrevious Shift+Left sent=" + std::to_wstring(i + 1));
             Sleep(25);
         }
         return valid() && GetForegroundWindow() == target;
@@ -433,7 +438,10 @@ bool selectPrevious(size_t count, const std::function<bool()> &valid)
             add(VK_LEFT, KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP);
         }
         add(VK_SHIFT, KEYEVENTF_KEYUP);
-        if (SendInput((UINT)inputs.size(), inputs.data(), sizeof(INPUT)) != inputs.size())
+        auto sent = SendInput((UINT)inputs.size(), inputs.data(), sizeof(INPUT));
+        diagnosticEvent(L"SelectPrevious batch offset=" + std::to_wstring(offset) + L" eventsRequested=" +
+            std::to_wstring(inputs.size()) + L" eventsSent=" + std::to_wstring(sent));
+        if (sent != inputs.size())
             return false;
     }
     return valid();
@@ -573,7 +581,7 @@ DiagnosticBuffer diagnosticBuffer;
 }
 std::wstring DiagnosticBuffer::record(const std::wstring &message, bool problem, ULONGLONG now)
 {
-    while (!entries.empty() && (entries.size() >= 40 || now - entries.front().first > 30000))
+    while (!entries.empty() && (entries.size() >= 128 || now - entries.front().first > 30000))
         entries.pop_front();
     entries.emplace_back(now, message);
     if (!problem)

src/screenshot.cpp

@@ -1,4 +1,5 @@
 #include "screenshot.h"
+#include "stroke_improvement.h"
 #include "ocr.h"
 #include "../resources/resource.h"
 #include <algorithm>
@@ -28,8 +29,8 @@ bool confirmScreenshotClose(HWND owner)
     dialog.hMainIcon=icon;
     dialog.dwCommonButtons=TDCBF_YES_BUTTON|TDCBF_NO_BUTTON;
     dialog.pszWindowTitle=L"KSwitcher";
-    dialog.pszMainInstruction=L"Close without copying?";
+    dialog.pszMainInstruction=L"Close without saving or copying?";
-    dialog.pszContent=L"Your latest screenshot changes have not been copied to the clipboard.";
+    dialog.pszContent=L"Your latest screenshot changes have not been saved to a file or copied to the clipboard.";
     dialog.nDefaultButton=IDNO;
     dialog.lpCallbackData=(LONG_PTR)owner;
     dialog.pfCallback=[](HWND window,UINT notification,WPARAM,LPARAM,LONG_PTR data)->HRESULT {
@@ -53,7 +54,7 @@ bool confirmScreenshotClose(HWND owner)
     // If Windows cannot display the confirmation, keep the screenshot open.
     return SUCCEEDED(result) && button==IDYES;
 }
-constexpr int ToolIds[]{27,10,11,22,23,24,25,21,19,26,20,12,18,13};
+constexpr int ToolIds[]{27,10,11,22,23,24,25,36,37,21,19,26,20,12,18,13};
 struct Surface
 {
     HDC dc = CreateCompatibleDC(nullptr);
@@ -123,7 +124,7 @@ bool chooseTextFont(HWND owner,Mark &m)
     m.fontWeight=font.lfWeight; m.fontItalic=font.lfItalic!=0;
     return true;
 }
-constexpr int CursorTools[]{10,11,22,23,24,25,19};
+constexpr int CursorTools[]{10,11,22,23,24,25,36,37,19};
 HCURSOR makeToolCursor(int tool,int size)
 {
     // Monochrome AND/XOR cursor: white outline keeps the glyph visible on dark images.
@@ -148,6 +149,8 @@ HCURSOR makeToolCursor(int tool,int size)
         case 23: Rectangle(dc,x(17),y(18),x(30),y(29)); break;
         case 24: Ellipse(dc,x(17),y(17),x(30),y(30)); break;
         case 25: Ellipse(dc,x(16),y(20),x(31),y(28)); break;
+        case 36: { POINT p[]{{x(23),y(17)},{x(31),y(30)},{x(16),y(30)},{x(23),y(17)}}; Polyline(dc,p,4); break; }
+        case 37: { POINT p[]{{x(20),y(18)},{x(27),y(18)},{x(31),y(30)},{x(16),y(30)},{x(20),y(18)}}; Polyline(dc,p,5); break; }
         case 19:
             line(18,25,25,18); line(25,18,29,22); line(29,22,22,29);
             line(22,29,18,25); line(18,25,17,30); line(17,30,22,29); break;
@@ -179,12 +182,18 @@ struct Capture
     COLORREF customColors[16]{};
     Mark stroke{};
     bool strokeConstrained{};
+    bool strokeUsedConstraint{};
     size_t strokeAnchor{};
     int strokeAxis{}; // 0 = not chosen, 1 = horizontal, 2 = vertical, 3/4 = diagonals.
     bool strokeAxisSettled{};
     std::vector<POINT> strokeMotion;
     POINT start{}, end{};
     RECT selection{}, view{};
+    RECT canvas{};
+    double zoom=1,panX=0,panY=0;
+    bool panning=false;
+    POINT panOrigin{};
+    int zoomWheelDelta=0;
     std::vector<Mark> marks;
     ScreenshotHistory history;
     HWND editor{}, inlineText{};
@@ -208,6 +217,7 @@ struct Capture
     int hoveredTool=0;
     MarkPart hoveredPart=MarkPart::None;
     std::wstring statusText;
+    std::filesystem::path savedPath;
     explicit Capture(ScreenshotHost &a) : app(a), autoOpenEditor(a.autoOpenEditor) {}
     ~Capture() {
         if(pencilCursor) DestroyCursor(pencilCursor);
@@ -239,11 +249,13 @@ void updateStatus(Capture &c)
         if(c.hoveredTool==30) text=L"Line style: solid, dotted, dashed or dash-dot";
         if(c.hoveredTool==31) text=L"Line ends: start, end, both or no arrowheads";
         if(c.hoveredTool==35) text=L"Arrow caption: F2 / double-click to edit; drag to reposition";
+        if(c.hoveredTool==28) text=L"Save (Ctrl+S) | Save As... (Ctrl+Shift+S)";
     }
     else if(c.inlineText) text=L"Text: Enter = new line | Ctrl+Enter = apply | Esc = cancel";
-    else if(part==MarkPart::Rotation) text=L"Drag to rotate text | Hold Shift for 15-degree steps";
+    else if(part==MarkPart::Rotation) text=L"Drag to rotate | Hold Shift for 15-degree steps";
     else if(part==MarkPart::Thickness) text=L"Drag to change thickness | Mouse wheel over object = size";
     else if(part==MarkPart::Radius) text=L"Drag to resize the number | Mouse wheel = diameter";
+    else if(part>=MarkPart::Vertex0 && part<=MarkPart::Vertex2) text=L"Drag triangle vertex | Other vertices stay fixed";
     else if(part==MarkPart::Start || part==MarkPart::End) text=L"Drag handle to resize | Endpoints can snap to objects and other arrows";
     else if(c.selected>=0) {
         const auto &m=c.marks[c.selected];
@@ -255,9 +267,11 @@ void updateStatus(Capture &c)
     else if(c.pointer) text=L"Pointer (V): select and edit objects | Drag handles = geometry or thickness | Empty space clears selection";
     else if(c.textTool) text=L"Text (T): click the image to type | Double-click existing text to edit";
     else if(c.highlight) text=L"Highlight (H): drag to paint | Ctrl+drag = paint over an object | V = pointer";
-    else if(c.freehand) text=L"Freehand (F): Shift = 45-degree steps; move >50 px off line to turn | Ctrl = draw over objects";
+    else if(c.freehand) text=L"Freehand (F): auto-smooth / shapes; Ctrl+Z restores original | Shift = 45-degree steps | Ctrl = draw over objects";
     else if(c.arrow) text=L"Drag to draw | Ctrl+drag over objects = linked connector | V = pointer";
     else text=L"Number (N): click to add | V = select and edit | Ctrl+C = copy screenshot";
+    text=L"Zoom: "+std::to_wstring(int(std::lround(100.0*(c.view.right-c.view.left)/c.image->width)))+
+         L"% (Ctrl +/- / wheel; Ctrl+0: fit; middle drag: pan) | "+text;
     if(text!=c.statusText) {
         c.statusText=std::move(text);
         SendMessageW(status,SB_SETTEXTW,0,(LPARAM)c.statusText.c_str());
@@ -297,6 +311,12 @@ void positionInlineText(Capture &c)
     int width=std::min(std::max(120,MulDiv(bounds.right-bounds.left,viewWidth,c.image->width)+24),std::max(32,int(client.right)-x));
     int height=std::min(std::max(40,MulDiv(bounds.bottom-bounds.top,viewWidth,c.image->width)+24),std::max(32,int(client.bottom)-c.statusHeight-y));
     SetWindowPos(c.inlineText,nullptr,x-2,y-2,width,height,SWP_NOZORDER|SWP_NOACTIVATE);
+    RECT editorBounds{x-2,y-2,x-2+width,y-2+height},visible{};
+    IntersectRect(&visible,&editorBounds,&c.canvas);
+    auto clip=IsRectEmpty(&visible)?CreateRectRgn(0,0,0,0):
+        CreateRectRgn(visible.left-editorBounds.left,visible.top-editorBounds.top,
+                      visible.right-editorBounds.left,visible.bottom-editorBounds.top);
+    if(!SetWindowRgn(c.inlineText,clip,TRUE)) DeleteObject(clip);
 }
 Mark textStyleDefaults(const Mark &source)
 {
@@ -337,6 +357,14 @@ void finishInlineText(HWND w,Capture &c,bool commit)
 }
 LRESULT CALLBACK inlineTextProc(HWND w,UINT msg,WPARAM wp,LPARAM lp,UINT_PTR,DWORD_PTR)
 {
+    if(msg==WM_KEYDOWN && (GetKeyState(VK_CONTROL)&0x8000) &&
+       (wp==VK_OEM_PLUS || wp==VK_ADD || wp==VK_OEM_MINUS || wp==VK_SUBTRACT || wp=='0' || wp==VK_NUMPAD0)) {
+        SendMessageW(GetParent(w),msg,wp,lp); return 0;
+    }
+    if(msg==WM_KEYDOWN && wp=='S' && (GetKeyState(VK_CONTROL)&0x8000)) {
+        PostMessageW(GetParent(w),WM_COMMAND,(GetKeyState(VK_SHIFT)&0x8000)?29:28,0); return 0;
+    }
+    if(msg==WM_CHAR && wp==19) return 0; // Ctrl+S is handled by the editor.
     if(msg==WM_KEYDOWN && (wp==VK_ESCAPE || (wp==VK_RETURN && (GetKeyState(VK_CONTROL)&0x8000)))) {
         PostMessageW(GetParent(w),FinishTextMessage,wp==VK_ESCAPE?2:1,(LPARAM)w); return 0;
     }
@@ -366,9 +394,47 @@ void beginMarkText(HWND w,Capture &c,int index)
         beginInlineText(w,c,label,index); c.editingLabel=true;
     }
 }
+POINT rotateShapePoint(const Mark &m,POINT p,double direction=1)
+{
+    if(m.shape==ScreenshotShape::None || m.rotation==0) return p;
+    double cx=(m.from.x+m.to.x)/2.0,cy=(m.from.y+m.to.y)/2.0;
+    double a=direction*m.rotation*3.141592653589793/180,cs=std::cos(a),sn=std::sin(a);
+    return {LONG(std::lround(cx+(p.x-cx)*cs-(p.y-cy)*sn)),
+            LONG(std::lround(cy+(p.x-cx)*sn+(p.y-cy)*cs))};
+}
+std::vector<POINT> shapeOutline(const Mark &m)
+{
+    auto points=m.points;
+    if(points.empty()) {
+        auto r=region(m.from,m.to);
+        if(m.shape==ScreenshotShape::Rectangle)
+            points={{r.left,r.top},{r.right,r.top},{r.right,r.bottom},{r.left,r.bottom},{r.left,r.top}};
+        else if(m.shape==ScreenshotShape::Triangle)
+            points={{(r.left+r.right)/2,r.top},{r.right,r.bottom},{r.left,r.bottom},{(r.left+r.right)/2,r.top}};
+        else if(m.shape==ScreenshotShape::Trapezoid)
+            points={{r.left+(r.right-r.left)/4,r.top},{r.right-(r.right-r.left)/4,r.top},
+                    {r.right,r.bottom},{r.left,r.bottom},{r.left+(r.right-r.left)/4,r.top}};
+        else {
+            for(int i=0;i<180;++i) {
+                double a=i*2*3.141592653589793/180;
+                points.push_back({LONG(std::lround((r.left+r.right)/2.0+(r.right-r.left)/2.0*std::cos(a))),
+                                  LONG(std::lround((r.top+r.bottom)/2.0+(r.bottom-r.top)/2.0*std::sin(a)))});
+            }
+            points.push_back(points.front());
+        }
+    }
+    for(auto &p:points) p=rotateShapePoint(m,p);
+    return points;
+}
 RECT markBounds(const Mark &m)
 {
     if(m.isText()) return screenshotTextBounds(m);
+    if(m.shape!=ScreenshotShape::None && m.rotation!=0) {
+        auto points=shapeOutline(m); RECT r{points[0].x,points[0].y,points[0].x,points[0].y};
+        for(auto p:points) { r.left=std::min(r.left,p.x); r.right=std::max(r.right,p.x);
+                            r.top=std::min(r.top,p.y); r.bottom=std::max(r.bottom,p.y); }
+        return r;
+    }
     RECT r=region(m.from,m.to);
     for(auto p:m.points) {
         r.left=std::min(r.left,p.x); r.top=std::min(r.top,p.y);
@@ -380,7 +446,7 @@ std::pair<POINT,POINT> thicknessSegment(const Mark &m)
 {
     if(m.shape!=ScreenshotShape::None) {
         auto r=region(m.from,m.to);
-        return {{r.right,r.top},{r.left,r.top}};
+        return {rotateShapePoint(m,{r.right,r.top}),rotateShapePoint(m,{r.left,r.top})};
     }
     if(m.freehand && m.points.size()>1) {
         size_t index=(m.points.size()-1)/2;
@@ -484,7 +550,10 @@ void drawMarks(HDC dc, const std::vector<Mark> &marks, const Mark *preview = nul
             if(m.shape!=ScreenshotShape::None) {
                 auto hollow=SelectObject(dc,GetStockObject(HOLLOW_BRUSH));
                 auto r=region(m.from,m.to);
-                if(m.shape==ScreenshotShape::Rectangle) Rectangle(dc,r.left,r.top,r.right+1,r.bottom+1);
+                if(!m.points.empty() || m.rotation!=0 || m.shape==ScreenshotShape::Triangle || m.shape==ScreenshotShape::Trapezoid) {
+                    auto points=shapeOutline(m); Polyline(dc,points.data(),int(points.size()));
+                }
+                else if(m.shape==ScreenshotShape::Rectangle) Rectangle(dc,r.left,r.top,r.right+1,r.bottom+1);
                 else Ellipse(dc,r.left,r.top,r.right+1,r.bottom+1);
                 SelectObject(dc,hollow);
                 SelectObject(dc,previousPen); DeleteObject(arrowPen);
@@ -599,7 +668,7 @@ void layout(HWND w, Capture &c)
     RECT statusRect{}; GetWindowRect(status,&statusRect);
     c.statusHeight=statusRect.bottom-statusRect.top;
     r.bottom-=c.statusHeight;
-    const int positions[]{8,44,80,116,152,188,224,260,296,332,368,416,452,500};
+    const int positions[]{8,44,80,116,152,188,224,260,296,332,368,404,440,488,524,572};
     static_assert(std::size(positions)==std::size(ToolIds));
     for (size_t i = 0; i < std::size(ToolIds); ++i)
     {
@@ -607,6 +676,9 @@ void layout(HWND w, Capture &c)
         MoveWindow(GetDlgItem(w,ToolIds[i]),MulDiv(positions[i],dpi,96),MulDiv(6,dpi,96),
                    MulDiv(32,dpi,96),MulDiv(32,dpi,96),TRUE);
     }
+    SendDlgItemMessageW(w,28,WM_SETFONT,(WPARAM)c.font,TRUE);
+    MoveWindow(GetDlgItem(w,28),MulDiv(612,dpi,96),MulDiv(6,dpi,96),
+               MulDiv(78,dpi,96),MulDiv(32,dpi,96),TRUE);
     c.panelHeight=c.unit+MulDiv(40,dpi,96);
     for(int id:{30,31,32,33,34,35}) SendDlgItemMessageW(w,id,WM_SETFONT,(WPARAM)c.font,TRUE);
     MoveWindow(GetDlgItem(w,32),MulDiv(12,dpi,96),c.unit+MulDiv(6,dpi,96),MulDiv(64,dpi,96),MulDiv(24,dpi,96),TRUE);
@@ -616,13 +688,35 @@ void layout(HWND w, Capture &c)
     MoveWindow(GetDlgItem(w,34),MulDiv(480,dpi,96),c.unit+MulDiv(2,dpi,96),MulDiv(28,dpi,96),MulDiv(28,dpi,96),TRUE);
     MoveWindow(GetDlgItem(w,35),MulDiv(516,dpi,96),c.unit+MulDiv(2,dpi,96),MulDiv(28,dpi,96),MulDiv(28,dpi,96),TRUE);
     syncLineOptions(w,c);
-    double ratio = std::min({1.0, double(std::max(1L,r.right-16))/c.image->width,
+    c.canvas={0,c.panelHeight,r.right,std::max(LONG(c.panelHeight+1),r.bottom)};
+    double ratio = c.zoom*std::min({1.0, double(std::max(1L,r.right-16))/c.image->width,
                                   double(std::max(1L,r.bottom-c.panelHeight-16))/c.image->height});
-    int width = int(c.image->width*ratio), height = int(c.image->height*ratio);
+    int width = std::max(1,int(std::lround(c.image->width*ratio))), height = std::max(1,int(std::lround(c.image->height*ratio)));
-    c.view = {(r.right-width)/2, c.panelHeight+(r.bottom-c.panelHeight-height)/2,
+    double maxX=std::max(0.0,(width-double(c.canvas.right-c.canvas.left))/2);
-              (r.right+width)/2, c.panelHeight+(r.bottom-c.panelHeight+height)/2};
+    double maxY=std::max(0.0,(height-double(c.canvas.bottom-c.canvas.top))/2);
+    c.panX=std::clamp(c.panX,-maxX,maxX); c.panY=std::clamp(c.panY,-maxY,maxY);
+    LONG x=LONG(std::lround((r.right-width)/2.0+c.panX));
+    LONG y=LONG(std::lround(c.panelHeight+(r.bottom-c.panelHeight-height)/2.0+c.panY));
+    c.view = {x,y,x+width,y+height};
     InvalidateRect(w, nullptr, FALSE);
 }
+void zoomCanvas(HWND w,Capture &c,double factor,POINT anchor,bool reset=false)
+{
+    if(!c.editing || c.dragging || c.panning) return;
+    double u=double(anchor.x-c.view.left)/std::max(1L,c.view.right-c.view.left);
+    double v=double(anchor.y-c.view.top)/std::max(1L,c.view.bottom-c.view.top);
+    double next=reset?1.0:std::clamp(c.zoom*factor,.1,16.0);
+    if(next==c.zoom && !reset) return;
+    c.zoom=next;
+    if(reset) c.panX=c.panY=0;
+    layout(w,c);
+    if(!reset) {
+        c.panX+=anchor.x-(c.view.left+u*(c.view.right-c.view.left));
+        c.panY+=anchor.y-(c.view.top+v*(c.view.bottom-c.view.top));
+        layout(w,c);
+    }
+    positionInlineText(c); updateStatus(c); InvalidateRect(w,nullptr,FALSE);
+}
 POINT imagePoint(Capture &c, POINT p, bool clamp = true)
 {
     POINT result{MulDiv(p.x-c.view.left,c.image->width,std::max(1L,c.view.right-c.view.left)),
@@ -650,6 +744,10 @@ std::pair<int,MarkPart> markAt(Capture &c, POINT p)
     if(c.selected>=0)
     {
         const auto &m=c.marks[c.selected];
+        if(m.shape!=ScreenshotShape::None) {
+            auto grip=screenshotShapeRotationHandle(m,double(c.unit)*c.image->width/std::max(1L,c.view.right-c.view.left));
+            if(std::hypot(double(p.x-grip.x),double(p.y-grip.y))<=tolerance) return {c.selected,MarkPart::Rotation};
+        }
         if(m.isText() || (m.isLine() && !m.label.empty())) {
             auto text=m.isText()?m:screenshotArrowLabel(m);
             auto grip=screenshotTextRotationHandle(text,double(c.unit*0.6)*c.image->width/std::max(1L,c.view.right-c.view.left));
@@ -673,7 +771,7 @@ HCURSOR toolCursor(const Capture &c)
     if(c.pointer) return LoadCursorW(nullptr,IDC_ARROW);
     if(c.textTool) return LoadCursorW(nullptr,IDC_IBEAM);
     if(c.freehand && c.pencilCursor) return c.pencilCursor;
-    int tool=c.highlight?19:c.straight?22:c.shape!=ScreenshotShape::None?22+int(c.shape):c.arrow?11:10;
+    int tool=c.highlight?19:c.straight?22:c.shape==ScreenshotShape::Trapezoid?37:c.shape==ScreenshotShape::Triangle?36:c.shape!=ScreenshotShape::None?22+int(c.shape):c.arrow?11:10;
     for(size_t i=0;i<std::size(CursorTools);++i)
         if(CursorTools[i]==tool && c.drawingCursors[i]) return c.drawingCursors[i];
     return LoadCursorW(nullptr,IDC_CROSS);
@@ -684,6 +782,7 @@ HCURSOR actionCursor(const Capture &c,std::pair<int,MarkPart> hit,bool inside)
     LPCWSTR cursor=nullptr;
     if(hit.second==MarkPart::Body || hit.second==MarkPart::Label) cursor=IDC_SIZEALL;
     else if(hit.second==MarkPart::Rotation) cursor=IDC_HAND;
+    else if(hit.second>=MarkPart::Vertex0 && hit.second<=MarkPart::Vertex2) cursor=IDC_SIZEALL;
     else if(hit.second==MarkPart::Radius) cursor=IDC_SIZEWE;
     else if(hit.second==MarkPart::Start || hit.second==MarkPart::End || hit.second==MarkPart::Thickness) {
         const auto &mark=c.marks[hit.first];
@@ -699,7 +798,7 @@ HCURSOR actionCursor(const Capture &c,std::pair<int,MarkPart> hit,bool inside)
 void captureCursor(HWND w, Capture &c)
 {
     POINT p; GetCursorPos(&p); ScreenToClient(w,&p);
-    bool inside=PtInRect(&c.view,p)!=FALSE;
+    bool inside=PtInRect(&c.view,p) && PtInRect(&c.canvas,p);
     auto hit=c.editing?(c.dragging?std::pair{c.selected,c.part}:markAt(c,imagePoint(c,p,false))):std::pair{-1,MarkPart::None};
     if(!c.dragging && !inside && hit.second!=MarkPart::Thickness && hit.second!=MarkPart::Rotation) hit={-1,MarkPart::None};
     SetCursor(actionCursor(c,hit,inside || c.dragging));
@@ -755,7 +854,18 @@ void drawHandles(HDC dc, const Capture &c)
         handle({m.from.x+m.radius,m.from.y});
     }
     else {
-        handle(m.from); handle(m.to);
+        if(m.shape==ScreenshotShape::Triangle) {
+            auto vertices=shapeOutline(m);
+            for(size_t i=0;i<3;++i) handle(vertices[i]);
+        } else { handle(rotateShapePoint(m,m.from)); handle(rotateShapePoint(m,m.to)); }
+        if(m.shape!=ScreenshotShape::None) {
+            auto r=region(m.from,m.to);
+            auto top=point(rotateShapePoint(m,{(r.left+r.right)/2,r.top}));
+            auto grip=screenshotShapeRotationHandle(m,double(c.unit)*c.image->width/std::max(1L,c.view.right-c.view.left));
+            auto end=point(grip); MoveToEx(dc,top.x,top.y,nullptr); LineTo(dc,end.x,end.y);
+            int radius=std::max(4,c.unit/8);
+            Ellipse(dc,end.x-radius,end.y-radius,end.x+radius+1,end.y+radius+1);
+        }
         auto [from,to]=thicknessSegment(m);
         auto mid=point({(from.x+to.x)/2,(from.y+to.y)/2});
         auto grip=thicknessHandle(c,m),end=point(grip);
@@ -771,7 +881,8 @@ void drawTool(const DRAWITEMSTRUCT &item, const Capture &c)
     RECT r=item.rcItem;
     bool active=(item.CtlID==27 && c.pointer)||(item.CtlID==10 && !c.pointer && !c.arrow && !c.highlight && !c.freehand && !c.textTool)||(item.CtlID==11 && c.arrow && !c.straight && c.shape==ScreenshotShape::None)||
                 (item.CtlID==19 && c.highlight)||(item.CtlID==21 && c.freehand)||
-                (item.CtlID==22 && c.straight)||(item.CtlID>=23 && item.CtlID<=25 && int(c.shape)==int(item.CtlID)-22)||(item.CtlID==26 && c.textTool);
+                (item.CtlID==22 && c.straight)||(item.CtlID>=23 && item.CtlID<=25 && int(c.shape)==int(item.CtlID)-22)||(item.CtlID==26 && c.textTool)||
+                (item.CtlID==36 && c.shape==ScreenshotShape::Triangle)||(item.CtlID==37 && c.shape==ScreenshotShape::Trapezoid);
     bool disabled=item.itemState&ODS_DISABLED;
     POINT mouse; GetCursorPos(&mouse); ScreenToClient(item.hwndItem,&mouse);
     bool hover=PtInRect(&r,mouse) && !disabled;
@@ -785,7 +896,16 @@ void drawTool(const DRAWITEMSTRUCT &item, const Capture &c)
     RoundRect(dc,r.left,r.top,r.right,r.bottom,corner,corner);
     SelectObject(dc,oldPen); SelectObject(dc,oldBrush); DeleteObject(pen); DeleteObject(brush);
     int iconIndex=item.CtlID==35?13:item.CtlID==34?14:item.CtlID>=22?int(item.CtlID)-13:item.CtlID==18?5:item.CtlID==19?6:item.CtlID==20?7:item.CtlID==21?8:item.CtlID-10;
-    auto icon=item.CtlID==27?(HICON)LoadCursorW(nullptr,IDC_ARROW):c.toolIcons[disabled?2:active?1:0][iconIndex];
+    auto icon=(item.CtlID==36 || item.CtlID==37)?nullptr:item.CtlID==27?(HICON)LoadCursorW(nullptr,IDC_ARROW):c.toolIcons[disabled?2:active?1:0][iconIndex];
+    if(item.CtlID==36 || item.CtlID==37) {
+        int cx=(r.left+r.right)/2,cy=(r.top+r.bottom)/2,s=c.iconSize/2;
+        auto trianglePen=CreatePen(PS_SOLID,std::max(1,MulDiv(2,GetDpiForWindow(item.hwndItem),96)),
+                                  disabled?RGB(148,163,184):active?RGB(37,99,235):RGB(51,65,85));
+        auto previous=SelectObject(dc,trianglePen);
+        if(item.CtlID==36) { POINT vertices[]{{cx,cy-s},{cx+s,cy+s},{cx-s,cy+s},{cx,cy-s}}; Polyline(dc,vertices,4); }
+        else { POINT vertices[]{{cx-s/2,cy-s},{cx+s/2,cy-s},{cx+s,cy+s},{cx-s,cy+s},{cx-s/2,cy-s}}; Polyline(dc,vertices,5); }
+        SelectObject(dc,previous); DeleteObject(trianglePen);
+    }
     if(icon) DrawIconEx(dc,(r.right-c.iconSize)/2,(r.bottom-c.iconSize)/2,icon,c.iconSize,c.iconSize,0,nullptr,DI_NORMAL);
     if(item.CtlID==20) {
         auto color=c.selected>=0?c.marks[c.selected].color:c.currentColor;
@@ -821,6 +941,64 @@ void copy(HWND w, Capture &c, DWORD (*publish)(HWND,const Clip &)=writeClipboard
     publish(c.app.window, clip);
     c.copied=true;
 }
+void saveToFile(HWND w, Capture &c, const std::filesystem::path &path)
+{
+    finishInlineText(w,c,true);
+    auto pixels=decodeImage(screenshotClip(c.image->dc,c.image->width,c.image->height,c.marks));
+    // GDI-rendered screenshot pixels are opaque; GDI does not maintain alpha.
+    for(size_t i=3;i<pixels.bgra.size();i+=4) pixels.bgra[i]=255;
+    auto bytes=encodePng(pixels);
+    GUID id{};
+    if(FAILED(CoCreateGuid(&id))) throw std::runtime_error("Cannot prepare screenshot output file");
+    wchar_t unique[40]{}; StringFromGUID2(id,unique,(int)std::size(unique));
+    auto temporary=path.parent_path()/(L".kswitcher-"+std::wstring(unique)+L".png");
+    try {
+        atomicWrite(temporary,bytes);
+        if(!MoveFileExW(temporary.c_str(),path.c_str(),MOVEFILE_REPLACE_EXISTING|MOVEFILE_WRITE_THROUGH))
+            throw std::runtime_error("Cannot save screenshot to the selected file");
+    } catch(...) {
+        std::error_code ignored; std::filesystem::remove(temporary,ignored); throw;
+    }
+    c.savedPath=path;
+    c.copied=true; // Current edits have been exported, either to file or clipboard.
+}
+void save(HWND w, Capture &c, bool saveAs=false,
+          BOOL (WINAPI *chooseFile)(LPOPENFILENAMEW)=GetSaveFileNameW)
+{
+    if(!saveAs && !c.savedPath.empty()) {
+        saveToFile(w,c,c.savedPath);
+        return;
+    }
+    wchar_t filename[32768]{};
+    auto proposed=c.savedPath.wstring();
+    if(proposed.empty()) {
+        SYSTEMTIME time{}; GetLocalTime(&time);
+        wchar_t name[100]{};
+        swprintf_s(name,L"Screenshot-%04u%02u%02u-%02u%02u%02u.png",
+                   time.wYear,time.wMonth,time.wDay,time.wHour,time.wMinute,time.wSecond);
+        proposed=name;
+    }
+    if(proposed.size()>=std::size(filename)) throw std::runtime_error("Screenshot file path is too long");
+    std::copy(proposed.begin(),proposed.end(),filename);
+    OPENFILENAMEW dialog{sizeof(dialog)};
+    dialog.hwndOwner=w;
+    dialog.lpstrTitle=L"Save screenshot";
+    dialog.lpstrFilter=L"PNG image (*.png)\0*.png\0\0";
+    dialog.nFilterIndex=1;
+    dialog.lpstrFile=filename;
+    dialog.nMaxFile=(DWORD)std::size(filename);
+    dialog.lpstrDefExt=L"png";
+    dialog.Flags=OFN_OVERWRITEPROMPT|OFN_PATHMUSTEXIST|OFN_NOCHANGEDIR|OFN_EXPLORER;
+    if(!chooseFile(&dialog)) {
+        if(CommDlgExtendedError()) throw std::runtime_error("Cannot open the screenshot save dialog");
+        return;
+    }
+    if(lower(std::filesystem::path(filename).extension().wstring())!=L".png")
+        throw std::runtime_error("Choose a filename ending in .png for the screenshot");
+    saveToFile(w,c,filename);
+    c.statusText=L"Saved: "+c.savedPath.wstring();
+    SendDlgItemMessageW(w,50,SB_SETTEXTW,0,(LPARAM)c.statusText.c_str());
+}
 void edit(HWND w, Capture &c)
 {
     auto r = region(c.start,c.end);
@@ -846,9 +1024,12 @@ void edit(HWND w, Capture &c)
     InitCommonControlsEx(&statusControls);
     CreateWindowExW(0,STATUSCLASSNAMEW,L"",WS_CHILD|WS_VISIBLE|SBARS_TOOLTIPS,
         0,0,0,0,w,(HMENU)50,c.app.instance,nullptr);
-    const wchar_t *labels[]{L"Pointer (V): select and edit objects", L"Number (N)", L"Arrow (A); Ctrl+drag between objects to link", L"Straight line (L); Ctrl+drag between objects to link", L"Rectangle (R)", L"Circle (O)", L"Ellipse (E)", L"Freehand line (F); Shift for 45-degree steps; move >50 px off line to turn; Ctrl to draw over objects", L"Highlight (H); Ctrl+drag to paint over an object",
+    const wchar_t *labels[]{L"Pointer (V): select and edit objects", L"Number (N)", L"Arrow (A); Ctrl+drag between objects to link", L"Straight line (L); Ctrl+drag between objects to link", L"Rectangle (R)", L"Circle (O)", L"Ellipse (E)", L"Triangle (G): drag to draw; drag each vertex to reshape", L"Trapezoid (B): drag to draw", L"Freehand line (F); Shift for 45-degree steps; move >50 px off line to turn; Ctrl to draw over objects", L"Highlight (H); Ctrl+drag to paint over an object",
         L"Text (T); double-click or F2 to edit", L"Color — selected object and new objects", L"Undo (Ctrl+Z)", L"Redo (Ctrl+Y / Ctrl+Shift+Z)", L"Copy (Ctrl+C)"};
     static_assert(std::size(labels)==std::size(ToolIds));
+    auto saveButton=CreateWindowW(L"BUTTON",L"Save...",WS_CHILD|WS_VISIBLE|WS_TABSTOP|BS_PUSHBUTTON,
+        0,0,0,0,w,(HMENU)28,c.app.instance,nullptr);
+    SetWindowSubclass(saveButton,toolHover,1,0);
     auto tips=CreateWindowExW(WS_EX_TOPMOST,TOOLTIPS_CLASSW,nullptr,WS_POPUP|TTS_ALWAYSTIP|TTS_NOPREFIX,
                              CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,w,nullptr,c.app.instance,nullptr);
     for (size_t i=0;i<std::size(ToolIds);++i)
@@ -938,7 +1119,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             }
             break;
         case WM_DRAWITEM:
-            if((wp>=10 && wp<=13) || (wp>=18 && wp<=27) || wp==34 || wp==35) { drawTool(*reinterpret_cast<DRAWITEMSTRUCT *>(lp),*c); return TRUE; }
+            if((wp>=10 && wp<=13) || (wp>=18 && wp<=27) || wp==34 || wp==35 || wp==36 || wp==37) { drawTool(*reinterpret_cast<DRAWITEMSTRUCT *>(lp),*c); return TRUE; }
             break;
         case WM_CTLCOLORSTATIC:
             SetBkColor((HDC)wp,RGB(255,255,255)); SetTextColor((HDC)wp,RGB(51,65,85));
@@ -1023,19 +1204,22 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 if(next!=value) { c->remember(c->marks); value=next; resolveScreenshotLinks(c->marks); }
             }
             if (LOWORD(wp)==13) { copy(w,*c); return 0; }
+            if (LOWORD(wp)==28 || LOWORD(wp)==29) {
+                save(w,*c,LOWORD(wp)==29); SetFocus(w); return 0;
+            }
             if (LOWORD(wp)==12 || LOWORD(wp)==18)
             {
                 bool changed=LOWORD(wp)==12?c->history.undo(c->marks):c->history.redo(c->marks);
                 if(changed) { c->copied=false; c->selected=-1; c->selectedLabel=false; c->wheelDelta=0; c->wheelTarget=-1; }
                 c->syncHistory();
             }
-            if (LOWORD(wp)==10 || LOWORD(wp)==11 || LOWORD(wp)==19 || (LOWORD(wp)>=21 && LOWORD(wp)<=27))
+            if (LOWORD(wp)==10 || LOWORD(wp)==11 || LOWORD(wp)==19 || LOWORD(wp)==36 || LOWORD(wp)==37 || (LOWORD(wp)>=21 && LOWORD(wp)<=27))
             {
                 c->pointer=LOWORD(wp)==27;
-                c->arrow = LOWORD(wp)==11 || (LOWORD(wp)>=22 && LOWORD(wp)<=25);
+                c->arrow = LOWORD(wp)==11 || LOWORD(wp)==36 || LOWORD(wp)==37 || (LOWORD(wp)>=22 && LOWORD(wp)<=25);
                 c->straight=LOWORD(wp)==22;
                 c->textTool=LOWORD(wp)==26;
-                c->shape=LOWORD(wp)>=23 && LOWORD(wp)<=25?ScreenshotShape(LOWORD(wp)-22):ScreenshotShape::None;
+                c->shape=LOWORD(wp)==37?ScreenshotShape::Trapezoid:LOWORD(wp)==36?ScreenshotShape::Triangle:LOWORD(wp)>=23 && LOWORD(wp)<=25?ScreenshotShape(LOWORD(wp)-22):ScreenshotShape::None;
                 c->selected=-1; c->selectedLabel=false;
                 c->highlight=LOWORD(wp)==19;
                 c->freehand=LOWORD(wp)==21;
@@ -1046,12 +1230,15 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 InvalidateRect(GetDlgItem(w,19),nullptr,FALSE);
                 InvalidateRect(GetDlgItem(w,21),nullptr,FALSE);
                 for(int id=22;id<=27;++id) InvalidateRect(GetDlgItem(w,id),nullptr,FALSE);
+                InvalidateRect(GetDlgItem(w,36),nullptr,FALSE);
+                InvalidateRect(GetDlgItem(w,37),nullptr,FALSE);
             }
 
             SetFocus(w); captureCursor(w,*c); InvalidateRect(w,nullptr,FALSE); return 0;
         case WM_KEYDOWN:
             if(wp==VK_SHIFT && c->editing && c->dragging && c->freehand && c->part==MarkPart::None && !c->strokeConstrained) {
                 c->strokeConstrained=true;
+                c->strokeUsedConstraint=true;
                 c->strokeAnchor=c->stroke.points.size()-1;
                 c->strokeAxis=0;
                 c->strokeAxisSettled=false;
@@ -1063,6 +1250,12 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             }
             if (c->editing && !c->dragging)
             {
+                if((GetKeyState(VK_CONTROL)&0x8000) &&
+                   (wp==VK_OEM_PLUS || wp==VK_ADD || wp==VK_OEM_MINUS || wp==VK_SUBTRACT || wp=='0' || wp==VK_NUMPAD0)) {
+                    POINT center{(c->canvas.left+c->canvas.right)/2,(c->canvas.top+c->canvas.bottom)/2};
+                    zoomCanvas(w,*c,wp==VK_OEM_MINUS || wp==VK_SUBTRACT?1/1.25:1.25,center,wp=='0' || wp==VK_NUMPAD0);
+                    return 0;
+                }
                 if(wp>=VK_LEFT && wp<=VK_DOWN && c->selected>=0 && !c->inlineText) {
                     POINT delta{wp==VK_LEFT?-1L:wp==VK_RIGHT?1L:0L,wp==VK_UP?-1L:wp==VK_DOWN?1L:0L};
                     const auto &original=c->marks[c->selected];
@@ -1079,6 +1272,9 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                     beginMarkText(w,*c,c->selected); return 0;
                 }
                 if ((GetKeyState(VK_CONTROL)&0x8000) && wp=='C') { copy(w,*c); return 0; }
+                if ((GetKeyState(VK_CONTROL)&0x8000) && wp=='S') {
+                    save(w,*c,(GetKeyState(VK_SHIFT)&0x8000)!=0); SetFocus(w); return 0;
+                }
                 if ((GetKeyState(VK_CONTROL)&0x8000) && (wp=='Z' || wp=='Y'))
                     SendMessageW(w,WM_COMMAND,wp=='Y'||(GetKeyState(VK_SHIFT)&0x8000)?18:12,0);
                 if ((GetKeyState(VK_CONTROL)&0x8000) && wp=='D' && c->selected>=0)
@@ -1094,6 +1290,8 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                     if(wp=='R') SendMessageW(w,WM_COMMAND,23,0);
                     if(wp=='O') SendMessageW(w,WM_COMMAND,24,0);
                     if(wp=='E') SendMessageW(w,WM_COMMAND,25,0);
+                    if(wp=='G') SendMessageW(w,WM_COMMAND,36,0);
+                    if(wp=='B') SendMessageW(w,WM_COMMAND,37,0);
                 }
                 if (wp=='N' || wp=='A') SendMessageW(w,WM_COMMAND,wp=='N'?10:11,0);
                 if(wp=='H') SendMessageW(w,WM_COMMAND,19,0);
@@ -1118,7 +1316,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
         case WM_LBUTTONDBLCLK:
             if(c->editing && !c->dragging) {
                 POINT p{GET_X_LPARAM(lp),GET_Y_LPARAM(lp)};
-                if(PtInRect(&c->view,p)) {
+                if(PtInRect(&c->view,p) && PtInRect(&c->canvas,p)) {
                     auto [index,part]=markAt(*c,imagePoint(*c,p));
                     if(index>=0 && (c->marks[index].isText() || c->marks[index].isLine())) {
                         c->selected=index; beginMarkText(w,*c,index);
@@ -1128,8 +1326,10 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             return 0;
         case WM_LBUTTONDOWN:
         {
+            if(c->panning) return 0;
             finishInlineText(w,*c,true);
             POINT p{GET_X_LPARAM(lp),GET_Y_LPARAM(lp)};
+            if(c->editing && !PtInRect(&c->canvas,p)) return 0;
             auto hitPart=c->editing?markAt(*c,imagePoint(*c,p,false)).second:MarkPart::None;
             bool thickness=hitPart==MarkPart::Thickness || hitPart==MarkPart::Rotation;
             if (c->editing && !PtInRect(&c->view,p) && !thickness)
@@ -1172,6 +1372,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                     c->stroke.freehand=c->freehand; c->stroke.style=c->lineStyle; c->stroke.ends=c->freehandEnds;
                     c->stroke.points.push_back(p);
                     c->strokeConstrained=false;
+                    c->strokeUsedConstraint=(wp&MK_SHIFT)!=0;
                 }
                 c->dragging=true; SetCapture(w);
             }
@@ -1179,8 +1380,17 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
         }
         case WM_MOUSEWHEEL:
         {
-            if(!c->editing || c->dragging) return 0;
+            if(!c->editing || c->dragging || c->panning) return 0;
             POINT p{GET_X_LPARAM(lp),GET_Y_LPARAM(lp)}; ScreenToClient(w,&p);
+            if(!PtInRect(&c->canvas,p)) return 0;
+            if(GET_KEYSTATE_WPARAM(wp)&MK_CONTROL) {
+                c->wheelDelta=0; c->wheelTarget=-1;
+                c->zoomWheelDelta+=GET_WHEEL_DELTA_WPARAM(wp);
+                int steps=c->zoomWheelDelta/WHEEL_DELTA; c->zoomWheelDelta%=WHEEL_DELTA;
+                if(steps) zoomCanvas(w,*c,std::pow(1.25,steps),p);
+                return 0;
+            }
+            c->zoomWheelDelta=0;
             if(!PtInRect(&c->view,p)) return 0;
             auto [index,part]=markAt(*c,imagePoint(*c,p));
             if(index<0) { c->wheelDelta=0; c->wheelTarget=-1; return 0; }
@@ -1200,8 +1410,27 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             }
             return 0;
         }
+        case WM_MBUTTONDOWN:
+        {
+            POINT p{GET_X_LPARAM(lp),GET_Y_LPARAM(lp)};
+            if(c->editing && !c->dragging && PtInRect(&c->canvas,p)) {
+                c->panning=true; c->panOrigin=p; SetCapture(w); SetCursor(LoadCursorW(nullptr,IDC_SIZEALL));
+            }
+            return 0;
+        }
+        case WM_MBUTTONUP:
+            if(c->panning) { c->panning=false; ReleaseCapture(); captureCursor(w,*c); }
+            return 0;
         case WM_MOUSEMOVE:
         case WM_LBUTTONUP:
+            if(c->panning) {
+                if(msg==WM_MOUSEMOVE) {
+                    POINT p{GET_X_LPARAM(lp),GET_Y_LPARAM(lp)};
+                    c->panX+=p.x-c->panOrigin.x; c->panY+=p.y-c->panOrigin.y; c->panOrigin=p;
+                    layout(w,*c); positionInlineText(*c); SetCursor(LoadCursorW(nullptr,IDC_SIZEALL));
+                }
+                return 0;
+            }
             if (c->dragging)
             {
                 POINT p{GET_X_LPARAM(lp),GET_Y_LPARAM(lp)};
@@ -1210,6 +1439,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                     c->end=constrainScreenshotShape(c->shape,c->start,c->end,c->image->width,c->image->height);
                 if(c->editing && (c->highlight || c->freehand) && c->part==MarkPart::None) {
                     bool constrained=c->freehand && ((wp&MK_SHIFT) || (GetKeyState(VK_SHIFT)&0x8000));
+                    c->strokeUsedConstraint=c->strokeUsedConstraint || constrained;
                     if(constrained) {
                         if(!c->strokeConstrained) {
                             c->strokeAnchor=c->stroke.points.size()-1;
@@ -1303,6 +1533,25 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                             linkScreenshotEndpoint(mark,false,c->end,c->marks,6);
                             resolveScreenshotLinks(c->marks);
                         }
+                        if(c->freehand && !c->strokeUsedConstraint &&
+                           !c->marks.back().fromNumber && !c->marks.back().toNumber &&
+                           !c->marks.back().fromLink.target && !c->marks.back().toLink.target) {
+                            ScreenshotShape recognized{};
+                            bool straightLine=false;
+                            auto improved=improveScreenshotStroke(c->marks.back().points,&recognized,&straightLine);
+                            if(!improved.empty()) {
+                                c->remember(c->marks);
+                                auto &mark=c->marks.back();
+                                mark.points=std::move(improved);
+                                mark.from=mark.points.front(); mark.to=mark.points.back();
+                                if(straightLine) { mark.points.clear(); mark.freehand=false; }
+                                if(recognized!=ScreenshotShape::None) {
+                                    mark.shape=recognized; mark.freehand=false; mark.ends=LineEnds::None;
+                                    auto bounds=markBounds(mark);
+                                    mark.from={bounds.left,bounds.top}; mark.to={bounds.right,bounds.bottom};
+                                }
+                            }
+                        }
                         c->selected=int(c->marks.size())-1; c->selectedLabel=false;
                     }
                     else if (std::hypot(double(c->end.x-c->start.x),double(c->end.y-c->start.y))>=4)
@@ -1313,6 +1562,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                         c->marks.back().style=c->lineStyle; c->marks.back().ends=c->straight || c->shape!=ScreenshotShape::None?LineEnds::None:c->arrowEnds;
                         c->marks.back().shape=c->shape;
                         auto &mark=c->marks.back();
+                        if(mark.shape==ScreenshotShape::Triangle || mark.shape==ScreenshotShape::Trapezoid) mark.points=shapeOutline(mark);
                         linkScreenshotEndpoint(mark,true,c->start,c->marks,6);
                         linkScreenshotEndpoint(mark,false,c->end,c->marks,6);
                         resolveScreenshotLinks(c->marks);
@@ -1325,6 +1575,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             captureCursor(w,*c);
             return 0;
         case WM_CAPTURECHANGED:
+            c->panning=false;
             if(c->dragging && c->part!=MarkPart::None)
             {
                 c->marks=std::move(c->beforeDrag); c->part=MarkPart::None;
@@ -1334,7 +1585,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             if (c->editing)
             {
                 auto limits = reinterpret_cast<MINMAXINFO *>(lp);
-                limits->ptMinTrackSize = {MulDiv(650,GetDpiForWindow(w),96),MulDiv(240,GetDpiForWindow(w),96)};
+                limits->ptMinTrackSize = {MulDiv(730,GetDpiForWindow(w),96),MulDiv(240,GetDpiForWindow(w),96)};
                 return 0;
             }
             break;
@@ -1384,7 +1635,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                     auto previous=SelectObject(buffer,divider);
                     MoveToEx(buffer,0,c->panelHeight-1,nullptr); LineTo(buffer,client.right,c->panelHeight-1);
                     int dpi=GetDpiForWindow(w);
-                    for(int x:{368,452}) {
+                    for(int x:{440,524}) {
                         MoveToEx(buffer,MulDiv(x,dpi,96),MulDiv(13,dpi,96),nullptr);
                         LineTo(buffer,MulDiv(x,dpi,96),MulDiv(31,dpi,96));
                     }
@@ -1402,9 +1653,12 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                     }
                     drawMarks(rendered.dc,visibleMarks,c->dragging && c->part==MarkPart::None?((c->highlight || c->freehand)?&c->stroke:&preview):nullptr);
                     SetStretchBltMode(buffer,HALFTONE); SetBrushOrgEx(buffer,0,0,nullptr);
+                    int savedCanvas=SaveDC(buffer);
+                    IntersectClipRect(buffer,c->canvas.left,c->canvas.top,c->canvas.right,c->canvas.bottom);
                     StretchBlt(buffer,c->view.left,c->view.top,c->view.right-c->view.left,c->view.bottom-c->view.top,
                                rendered.dc,0,0,rendered.width,rendered.height,SRCCOPY);
                     drawHandles(buffer,*c);
+                    RestoreDC(buffer,savedCanvas);
                     BitBlt(dc,0,0,width,height,buffer,0,0,SRCCOPY);
                 }
             }
@@ -1449,6 +1703,11 @@ POINT screenshotTextRotationHandle(const ScreenshotMark &m,double clearance)
     auto r=plainTextBounds(m);
     return rotateTextPoint(m,{(r.left+r.right)/2,r.top-LONG(std::lround(clearance))});
 }
+POINT screenshotShapeRotationHandle(const ScreenshotMark &m,double clearance)
+{
+    auto r=region(m.from,m.to);
+    return rotateShapePoint(m,{(r.left+r.right)/2,r.top-LONG(std::lround(clearance))});
+}
 ScreenshotMark screenshotArrowLabel(const ScreenshotMark &m)
 {
     ScreenshotMark label{{0,0},{0,0},0};
@@ -1528,23 +1787,23 @@ void assignMarkIds(std::vector<ScreenshotMark> &marks)
 }
 POINT objectAnchor(const ScreenshotMark &m,const ScreenshotLink &link)
 {
-    if(m.isText() || m.shape!=ScreenshotShape::None) {
+    if(m.isText() || (m.shape!=ScreenshotShape::None && m.points.empty())) {
         auto r=m.isText()?plainTextBounds(m):region(m.from,m.to);
         POINT p{LONG(std::lround(r.left+(r.right-r.left)*link.u)),LONG(std::lround(r.top+(r.bottom-r.top)*link.v))};
-        return m.isText()?rotateTextPoint(m,p):p;
+        return m.isText()?rotateTextPoint(m,p):rotateShapePoint(m,p);
     }
     size_t segments=m.points.size()>1?m.points.size()-1:1;
     double along=std::clamp(link.u,0.0,1.0)*segments;
     size_t i=std::min(size_t(along),segments-1); double t=along-i;
     POINT a=m.points.size()>1?m.points[i]:m.from,b=m.points.size()>1?m.points[i+1]:m.to;
-    return {LONG(std::lround(a.x+(b.x-a.x)*t)),LONG(std::lround(a.y+(b.y-a.y)*t))};
+    return rotateShapePoint(m,{LONG(std::lround(a.x+(b.x-a.x)*t)),LONG(std::lround(a.y+(b.y-a.y)*t))});
 }
 bool findObjectAnchor(const ScreenshotMark &m,POINT drop,double tolerance,ScreenshotLink &link)
 {
     link={m.id,0,0};
-    if(m.isText() || m.shape!=ScreenshotShape::None) {
+    if(m.isText() || (m.shape!=ScreenshotShape::None && m.points.empty())) {
         auto r=m.isText()?plainTextBounds(m):region(m.from,m.to);
-        POINT p=m.isText()?rotateTextPoint(m,drop,-1):drop;
+        POINT p=m.isText()?rotateTextPoint(m,drop,-1):rotateShapePoint(m,drop,-1);
         double w=std::max(1L,r.right-r.left),h=std::max(1L,r.bottom-r.top);
         double x=(p.x-r.left)/w,y=(p.y-r.top)/h;
         bool inside=x>=0 && x<=1 && y>=0 && y<=1;
@@ -1564,6 +1823,7 @@ bool findObjectAnchor(const ScreenshotMark &m,POINT drop,double tolerance,Screen
         auto anchor=objectAnchor(m,link);
         return inside || std::hypot(double(drop.x-anchor.x),double(drop.y-anchor.y))<=tolerance;
     }
+    drop=rotateShapePoint(m,drop,-1);
     double best=1e100;
     size_t segments=m.points.size()>1?m.points.size()-1:1;
     for(size_t i=0;i<segments;++i) {
@@ -1648,6 +1908,13 @@ void resolveScreenshotLinks(std::vector<ScreenshotMark> &marks)
 }
 MarkPart hitScreenshotMark(const ScreenshotMark &m, POINT p, double tolerance)
 {
+    if(m.shape==ScreenshotShape::Triangle) {
+        auto vertices=shapeOutline(m);
+        for(int i=0;i<3;++i)
+            if(std::hypot(double(p.x-vertices[i].x),double(p.y-vertices[i].y))<=tolerance)
+                return MarkPart(int(MarkPart::Vertex0)+i);
+    }
+    p=rotateShapePoint(m,p,-1);
     if(m.isText()) {
         auto r=plainTextBounds(m);
         auto local=rotateTextPoint(m,p,-1);
@@ -1658,8 +1925,10 @@ MarkPart hitScreenshotMark(const ScreenshotMark &m, POINT p, double tolerance)
     auto distance=[](POINT a, POINT b) { return std::hypot(double(a.x-b.x),double(a.y-b.y)); };
     if(!m.points.empty())
     {
-        if(m.freehand && distance(p,m.from)<=tolerance) return MarkPart::Start;
+        if(m.shape!=ScreenshotShape::Triangle) {
-        if(m.freehand && distance(p,m.to)<=tolerance) return MarkPart::End;
+            if((m.freehand || m.shape!=ScreenshotShape::None) && distance(p,m.from)<=tolerance) return MarkPart::Start;
+            if((m.freehand || m.shape!=ScreenshotShape::None) && distance(p,m.to)<=tolerance) return MarkPart::End;
+        }
         double reach=tolerance+std::clamp(m.thickness,m.isHighlight()?4:1,m.isHighlight()?100:30)/2.0;
         POINT from=m.points.front();
         for(auto to:m.points) {
@@ -1713,7 +1982,32 @@ ScreenshotMark dragScreenshotMark(const ScreenshotMark &original, MarkPart part,
 {
     auto m=original;
     if(position.x==origin.x && position.y==origin.y) return m;
-    if(part==MarkPart::Rotation && (m.isText() || (m.isLine() && !m.label.empty()))) {
+    if(part>=MarkPart::Vertex0 && part<=MarkPart::Vertex2 && m.shape==ScreenshotShape::Triangle) {
+        if(m.points.empty()) { auto local=m; local.rotation=0; m.points=shapeOutline(local); }
+        size_t index=size_t(int(part)-int(MarkPart::Vertex0)),fixed=(index+1)%3;
+        auto fixedWorld=rotateShapePoint(m,m.points[fixed]);
+        auto vertexWorld=rotateShapePoint(m,m.points[index]);
+        POINT target{std::clamp(vertexWorld.x+position.x-origin.x,0L,LONG(width-1)),
+                     std::clamp(vertexWorld.y+position.y-origin.y,0L,LONG(height-1))};
+        m.points[index]=rotateShapePoint(m,target,-1); m.points[3]=m.points[0];
+        RECT bounds{m.points[0].x,m.points[0].y,m.points[0].x,m.points[0].y};
+        for(size_t i=1;i<3;++i) {auto p=m.points[i]; bounds.left=std::min(bounds.left,p.x); bounds.right=std::max(bounds.right,p.x);
+            bounds.top=std::min(bounds.top,p.y); bounds.bottom=std::max(bounds.bottom,p.y);}
+        m.from={bounds.left,bounds.top}; m.to={bounds.right,bounds.bottom};
+        auto shifted=rotateShapePoint(m,m.points[fixed]);
+        LONG dx=fixedWorld.x-shifted.x,dy=fixedWorld.y-shifted.y;
+        m.from.x+=dx; m.to.x+=dx; m.from.y+=dy; m.to.y+=dy;
+        for(auto &p:m.points) {p.x+=dx;p.y+=dy;}
+    }
+    else if(part==MarkPart::Rotation && m.shape!=ScreenshotShape::None) {
+        double cx=(m.from.x+m.to.x)/2.0,cy=(m.from.y+m.to.y)/2.0;
+        if(std::hypot(position.x-cx,position.y-cy)<1) return m;
+        double a=std::atan2(origin.y-cy,origin.x-cx),b=std::atan2(position.y-cy,position.x-cx);
+        m.rotation+=(b-a)*180/3.141592653589793;
+        if(snapRotation) m.rotation=std::round(m.rotation/15)*15;
+        m.rotation=std::remainder(m.rotation,360);
+    }
+    else if(part==MarkPart::Rotation && (m.isText() || (m.isLine() && !m.label.empty()))) {
         if(position.x==origin.x && position.y==origin.y) return m;
         auto text=m.isText()?m:screenshotArrowLabel(m);
         auto r=plainTextBounds(text);
@@ -1767,13 +2061,34 @@ ScreenshotMark dragScreenshotMark(const ScreenshotMark &original, MarkPart part,
     }
     else if(part==MarkPart::Start || part==MarkPart::End)
     {
+        origin=rotateShapePoint(original,origin,-1);
+        position=rotateShapePoint(original,position,-1);
         (part==MarkPart::Start?m.fromNumber:m.toNumber)=0;
         (part==MarkPart::Start?m.fromLink:m.toLink)={};
         auto &endpoint=part==MarkPart::Start?m.from:m.to;
         endpoint.x=std::clamp(endpoint.x+position.x-origin.x,0L,LONG(width-1));
         endpoint.y=std::clamp(endpoint.y+position.y-origin.y,0L,LONG(height-1));
         endpoint=constrainScreenshotShape(m.shape,part==MarkPart::Start?m.to:m.from,endpoint,width,height);
+        if(m.shape!=ScreenshotShape::None && !m.points.empty()) {
+            if(m.from.x==m.to.x || m.from.y==m.to.y) return original;
+            // Resize the entire recognized outline, not just a pencil endpoint.
+            // Keep the opposite corner fixed, including when dragging across it.
+            double oldWidth=original.to.x-original.from.x,oldHeight=original.to.y-original.from.y;
+            for(auto &point:m.points) {
+                double u=oldWidth?(point.x-original.from.x)/oldWidth:0;
+                double v=oldHeight?(point.y-original.from.y)/oldHeight:0;
+                point={LONG(std::lround(m.from.x+u*(m.to.x-m.from.x))),
+                       LONG(std::lround(m.from.y+v*(m.to.y-m.from.y)))};
+            }
+        }
         if(m.freehand && !m.points.empty()) (part==MarkPart::Start?m.points.front():m.points.back())=endpoint;
+        if(m.shape!=ScreenshotShape::None && m.rotation!=0) {
+            auto fixedBefore=rotateShapePoint(original,part==MarkPart::Start?original.to:original.from);
+            auto fixedAfter=rotateShapePoint(m,part==MarkPart::Start?m.to:m.from);
+            LONG dx=fixedBefore.x-fixedAfter.x,dy=fixedBefore.y-fixedAfter.y;
+            m.from.x+=dx; m.to.x+=dx; m.from.y+=dy; m.to.y+=dy;
+            for(auto &p:m.points) {p.x+=dx;p.y+=dy;}
+        }
     }
     return m;
 }

src/screenshot.h

@@ -15,7 +15,7 @@ void showScreenshot(ScreenshotHost &);
 void showScreenshotEditor(ScreenshotHost &,const Clip &);
 enum class LineStyle { Solid, Dotted, Dashed, DashDot };
 enum class LineEnds { End, Start, Both, None };
-enum class ScreenshotShape { None, Rectangle, Circle, Ellipse };
+enum class ScreenshotShape { None, Rectangle, Circle, Ellipse, Triangle, Trapezoid };
 struct ScreenshotOffset { double x, y; };
 struct ScreenshotLink {
     unsigned long long target{};
@@ -40,7 +40,7 @@ struct ScreenshotMark {
     unsigned long long id{};
     ScreenshotLink fromLink, toLink;
     bool isText() const { return !text.empty(); }
-    bool isHighlight() const { return !points.empty() && !freehand; }
+    bool isHighlight() const { return !points.empty() && !freehand && shape==ScreenshotShape::None; }
     bool isLine() const { return !number && !isText() && !isHighlight() && shape==ScreenshotShape::None; }
 };
 class ScreenshotHistory {
@@ -55,7 +55,7 @@ class ScreenshotHistory {
 void resolveScreenshotLinks(std::vector<ScreenshotMark> &);
 void linkScreenshotEndpoint(ScreenshotMark &, bool start, POINT drop,
                             std::vector<ScreenshotMark> &, double tolerance);
-enum class MarkPart { None, Body, Start, End, Radius, Thickness, Rotation, Label };
+enum class MarkPart { None, Body, Start, End, Radius, Thickness, Rotation, Label, Vertex0, Vertex1, Vertex2 };
 POINT screenshotThicknessHandle(const ScreenshotMark &, double clearance = 16);
 ScreenshotMark cloneScreenshotMark(const ScreenshotMark &, const std::vector<ScreenshotMark> &, int width, int height);
 int nextScreenshotNumber(const std::vector<ScreenshotMark> &);
@@ -65,6 +65,7 @@ ScreenshotMark dragScreenshotMark(const ScreenshotMark &, MarkPart, POINT origin
 POINT constrainScreenshotShape(ScreenshotShape, POINT anchor, POINT position, int width, int height);
 RECT screenshotTextBounds(const ScreenshotMark &);
 POINT screenshotTextRotationHandle(const ScreenshotMark &, double clearance=24);
+POINT screenshotShapeRotationHandle(const ScreenshotMark &, double clearance=32);
 ScreenshotMark screenshotArrowLabel(const ScreenshotMark &);
 // Render at source resolution; never reads or writes the system clipboard.
 Clip screenshotClip(HDC source, int width, int height, const std::vector<ScreenshotMark> &marks);

src/storage.cpp

@@ -8,6 +8,22 @@
 namespace ks
 {
 using Json = nlohmann::json;
+std::wstring snippetId(const Snippet &snippet)
+{
+    if (!snippet.id.empty()) return snippet.id;
+    // Deterministic migration of pre-ID profiles on every existing device.
+    std::wstring id = L"legacy-";
+    const wchar_t *hex = L"0123456789abcdef";
+    for (unsigned char c : utf8(lower(snippet.trigger))) { id += hex[c >> 4]; id += hex[c & 15]; }
+    return id;
+}
+std::wstring newSnippetId()
+{
+    GUID guid{}; wchar_t text[40]{};
+    if (FAILED(CoCreateGuid(&guid))) throw std::runtime_error("Cannot create snippet ID.");
+    StringFromGUID2(guid, text, 40);
+    return text;
+}
 namespace
 {
 Bytes jsonBytes(const Json &j)
@@ -92,6 +108,19 @@ void validateSettings(const Settings &s)
             throw std::runtime_error("Unsupported auto-correction language");
     if (s.autoNever.size() > 10000 || s.autoExcluded.size() > 1000)
         throw std::runtime_error("Too many auto-correction exceptions");
+    if (s.autoReplacements.size() > 10000)
+        throw std::runtime_error("Too many automatic replacements");
+    for (const auto &[from, to] : s.autoReplacements)
+    {
+        bool valid = false;
+        for (auto alphabet : {L"abcdefghijklmnopqrstuvwxyz", L"абвгґдеєжзиіїйклмнопрстуфхцчшщьюя",
+                              L"абвгдеёжзийклмнопрстуфхцчшщъыьэюя"})
+            valid |= !from.empty() && !to.empty() && from.size() <= 32 && to.size() <= 32 &&
+                     from == lower(from) && to == lower(to) && from != to &&
+                     from.find_first_not_of(alphabet) == from.npos && to.find_first_not_of(alphabet) == to.npos;
+        if (!valid)
+            throw std::runtime_error("Replacement pairs must be different lowercase words of 1-32 letters in the same language");
+    }
     for (const auto &[language, words] : s.autoWords)
     {
         std::wstring alphabet = language == L"en" ? L"abcdefghijklmnopqrstuvwxyz" :
@@ -107,8 +136,14 @@ void validateSettings(const Settings &s)
         s.maxImageMiB > 64)
         throw std::runtime_error("History limits: 10–10000 items, 1–2048 MiB total, 1–64 MiB per image");
     std::set<std::wstring> seen;
+    std::set<std::wstring> ids;
+    for (const auto &id : s.snippetTombstones)
+        if (id.empty() || id.size() > 600 || !ids.insert(id).second)
+            throw std::runtime_error("Invalid snippet deletion record.");
     for (const auto &snippet : s.snippets)
     {
+        auto id = snippetId(snippet);
+        if (id.size() > 600 || !ids.insert(id).second) throw std::runtime_error("Duplicate snippet ID or deleted snippet.");
         if (snippet.trigger.size() < 2 || snippet.trigger.size() > 64 ||
             snippet.trigger.find_first_of(L"\r\n\t ") != snippet.trigger.npos)
             throw std::runtime_error("Snippet triggers must contain 2–64 characters without whitespace");
@@ -150,6 +185,15 @@ Settings decodeSettings(const Bytes &bytes, const std::vector<Layout> &layouts)
     s.elevatedAutostart = j.value("autostartAsAdministrator", false);
     s.awake = j.value("preventScreenLock", false);
     s.autoCorrect = j.value("autoCorrectLayout", false);
+    s.autoReplace = j.value("autoCorrectReplace", false);
+    s.autoTypos = j.value("autoCorrectTypos", false);
+    if (j.contains("autoCorrectReplacements"))
+        for (auto &[from, to] : j.at("autoCorrectReplacements").items())
+        {
+            auto key = lower(wide(from));
+            if (!s.autoReplacements.emplace(key, lower(wide(to.get<std::string>()))).second)
+                throw std::runtime_error("Duplicate automatic replacement");
+        }
     s.autoMaxRank = j.value("autoCorrectMaxRank", 0);
     s.autoMinLength = j.value("autoCorrectMinLength", 3);
     s.autoPrefixChars = str(j, "autoCorrectPrefixChars", s.autoPrefixChars);
@@ -203,7 +247,13 @@ Settings decodeSettings(const Bytes &bytes, const std::vector<Layout> &layouts)
     }
     if (j.contains("snippets"))
         for (auto &sn : j.at("snippets"))
-            s.snippets.push_back({str(sn, "trigger"), str(sn, "text")});
+        {
+            Snippet item{str(sn, "trigger"), str(sn, "text"), str(sn, "id")};
+            item.id = snippetId(item);
+            s.snippets.push_back(std::move(item));
+        }
+    if (j.contains("snippetTombstones"))
+        for (const auto &id : j.at("snippetTombstones")) s.snippetTombstones.push_back(wide(id.get<std::string>()));
     validateSettings(s);
     return s;
 }
@@ -240,6 +290,11 @@ Bytes encodeSettings(const Settings &s)
     for (auto &id : s.cycle)
         j["layouts"].push_back(utf8(id));
     j["autoCorrectLayout"] = s.autoCorrect;
+    j["autoCorrectReplace"] = s.autoReplace;
+    j["autoCorrectTypos"] = s.autoTypos;
+    j["autoCorrectReplacements"] = Json::object();
+    for (const auto &[from, to] : s.autoReplacements)
+        j["autoCorrectReplacements"][utf8(from)] = utf8(to);
     j["autoCorrectMaxRank"] = s.autoMaxRank;
     j["autoCorrectMinLength"] = s.autoMinLength;
     j["autoCorrectPrefixChars"] = utf8(s.autoPrefixChars);
@@ -264,7 +319,9 @@ Bytes encodeSettings(const Settings &s)
         j["layoutHotkeys"].push_back({{"layoutId", utf8(s.directIds[i])}, {"hotkey", utf8(s.direct[i])}});
     j["snippets"] = Json::array();
     for (auto &sn : s.snippets)
-        j["snippets"].push_back({{"trigger", utf8(sn.trigger)}, {"text", utf8(sn.text)}});
+        j["snippets"].push_back({{"trigger", utf8(sn.trigger)}, {"text", utf8(sn.text)}, {"id", utf8(snippetId(sn))}});
+    j["snippetTombstones"] = Json::array();
+    for (const auto &id : s.snippetTombstones) j["snippetTombstones"].push_back(utf8(id));
     j["excludedApps"] = Json::array();
     for (auto &name : s.excluded)
         j["excludedApps"].push_back(utf8(name));

src/stroke_improvement.h

@@ -0,0 +1,240 @@
+#pragma once
+#include "screenshot.h"
+#include <algorithm>
+#include <cmath>
+#include <vector>
+
+namespace ks::stroke_detail {
+struct Point { double x, y; };
+inline double distance(Point a, Point b) { return std::hypot(a.x-b.x,a.y-b.y); }
+inline double length(const std::vector<Point> &p) {
+    double total=0;
+    for(size_t i=1;i<p.size();++i) total+=distance(p[i-1],p[i]);
+    return total;
+}
+// Arc-length sampling makes fitting independent of mouse speed and bounds its cost.
+inline std::vector<Point> sample(const std::vector<Point> &p, size_t count) {
+    std::vector<Point> out{p.front()};
+    double step=length(p)/(count-1), traversed=0;
+    size_t segment=1;
+    for(size_t i=1;i+1<count;++i) {
+        double target=i*step;
+        while(segment+1<p.size() && traversed+distance(p[segment-1],p[segment])<target) {
+            traversed+=distance(p[segment-1],p[segment]); ++segment;
+        }
+        double span=distance(p[segment-1],p[segment]);
+        double t=span>0?(target-traversed)/span:0;
+        out.push_back({p[segment-1].x+t*(p[segment].x-p[segment-1].x),
+                       p[segment-1].y+t*(p[segment].y-p[segment-1].y)});
+    }
+    out.push_back(p.back()); return out;
+}
+inline double segmentDistance(Point p, Point a, Point b) {
+    double dx=b.x-a.x,dy=b.y-a.y,den=dx*dx+dy*dy;
+    double t=den?std::clamp(((p.x-a.x)*dx+(p.y-a.y)*dy)/den,0.0,1.0):0;
+    return distance(p,{a.x+t*dx,a.y+t*dy});
+}
+inline double cross(Point a, Point b, Point c) { return (b.x-a.x)*(c.y-a.y)-(b.y-a.y)*(c.x-a.x); }
+}
+
+namespace ks {
+// Returns a replacement path; an empty result means no visible improvement.
+// Report recognized geometry separately from a smoothed freehand path.
+inline std::vector<POINT> improveScreenshotStroke(const std::vector<POINT> &input, ScreenshotShape *shape=nullptr,
+                                                 bool *straightLine=nullptr) {
+    if(shape) *shape=ScreenshotShape::None;
+    if(straightLine) *straightLine=false;
+    using namespace stroke_detail;
+    if(input.size()<3) return {};
+    std::vector<Point> raw;
+    for(auto p:input) if(raw.empty() || distance(raw.back(),{double(p.x),double(p.y)})>0)
+        raw.push_back({double(p.x),double(p.y)});
+    double total=length(raw);
+    if(raw.size()>=3) {
+        double span=distance(raw.front(),raw.back());
+        if(span>=24 && total<=span*1.35) {
+            double tolerance=std::clamp(span*.03,2.0,6.0),maximum=0,backtracking=0,previous=0;
+            Point a=raw.front(),b=raw.back();
+            // Check every original point so a short excursion cannot disappear in resampling.
+            for(auto p:raw) {
+                maximum=std::max(maximum,segmentDistance(p,a,b));
+                double along=((p.x-a.x)*(b.x-a.x)+(p.y-a.y)*(b.y-a.y))/span;
+                backtracking+=std::max(0.0,previous-along); previous=along;
+            }
+            double squared=0;
+            for(auto p:sample(raw,64)) { double d=segmentDistance(p,a,b); squared+=d*d; }
+            if(maximum<=tolerance && std::sqrt(squared/64)<=tolerance*.7 &&
+               backtracking<=std::max(2.0,span*.02)) {
+                if(straightLine) *straightLine=true;
+                return {input.front(),input.back()};
+            }
+        }
+    }
+    if(raw.size()<5 || total<16) return {};
+    auto points=sample(raw,128);
+    double left=points[0].x,right=left,top=points[0].y,bottom=top;
+    for(auto p:points) { left=std::min(left,p.x); right=std::max(right,p.x); top=std::min(top,p.y); bottom=std::max(bottom,p.y); }
+    double scale=std::min(right-left,bottom-top);
+    std::vector<Point> best;
+    double bestScore=1e30;
+    double gap=distance(raw.front(),raw.back());
+    if(scale>=20 && gap<=scale*.5) {
+        auto consider=[&](std::vector<Point> candidate, ScreenshotShape kind=ScreenshotShape::Rectangle) {
+            bool oval=kind==ScreenshotShape::Circle || kind==ScreenshotShape::Ellipse;
+            if(!oval && gap>scale*.22) return;
+            double perimeter=length(candidate);
+            if(total<perimeter*.82 || total>perimeter*1.25) return;
+            auto probes=sample(candidate,128);
+            double sum=0,maximum=0;
+            auto measure=[&](const std::vector<Point> &a,const std::vector<Point> &b) {
+                for(auto p:a) {
+                    double d=1e30;
+                    for(size_t i=1;i<b.size();++i) d=std::min(d,segmentDistance(p,b[i-1],b[i]));
+                    sum+=d*d; maximum=std::max(maximum,d);
+                }
+            };
+            measure(points,candidate); measure(probes,points);
+            double score=std::sqrt(sum/256);
+            if(maximum<=std::max(3.0,scale*(oval?.22:.12)) && score<=std::max(1.5,scale*(oval?.085:.055)) && score<bestScore) {
+                bestScore=score; best=std::move(candidate);
+                if(shape) *shape=kind;
+            }
+        };
+        // Fit oriented bounding boxes; testing angles also handles tilted ovals.
+        for(int degrees=0;degrees<180;degrees+=5) {
+            double angle=degrees*3.141592653589793/180,cs=std::cos(angle),sn=std::sin(angle);
+            double x0=1e30,y0=x0,x1=-x0,y1=-x0;
+            for(auto p:points) {
+                double x=p.x*cs+p.y*sn,y=-p.x*sn+p.y*cs;
+                x0=std::min(x0,x); x1=std::max(x1,x); y0=std::min(y0,y); y1=std::max(y1,y);
+            }
+            auto world=[&](double x,double y)->Point { return {x*cs-y*sn,x*sn+y*cs}; };
+            consider({world(x0,y0),world(x1,y0),world(x1,y1),world(x0,y1),world(x0,y0)});
+            double rx=(x1-x0)/2,ry=(y1-y0)/2;
+            double cx=(x0+x1)/2,cy=(y0+y1)/2;
+            std::vector<Point> local;
+            for(auto p:points) local.push_back({p.x*cs+p.y*sn,-p.x*sn+p.y*cs});
+            // Fit four sides to their supporting samples. Extremal bounds exaggerate
+            // crooked corners and can unfairly make an oval score better than a box.
+            double sides[]{x0,x1,y0,y1};
+            bool supported=true;
+            for(int iteration=0;iteration<6;++iteration) {
+                double sums[4]{}; int counts[4]{};
+                for(auto p:local) {
+                    double distances[]{std::abs(p.x-sides[0]),std::abs(p.x-sides[1]),
+                                       std::abs(p.y-sides[2]),std::abs(p.y-sides[3])};
+                    auto side=std::min_element(distances,distances+4)-distances;
+                    sums[side]+=side<2?p.x:p.y; ++counts[side];
+                }
+                for(int side=0;side<4;++side) {
+                    if(counts[side]<10) { supported=false; break; }
+                    sides[side]=sums[side]/counts[side];
+                }
+                if(!supported) break;
+            }
+            if(supported && sides[1]-sides[0]>=16 && sides[3]-sides[2]>=16)
+                consider({world(sides[0],sides[2]),world(sides[1],sides[2]),
+                          world(sides[1],sides[3]),world(sides[0],sides[3]),world(sides[0],sides[2])});
+            // Fit the whole gesture instead of letting a single mouse wobble set the bounds.
+            auto error=[&](double x,double y,double a,double b) {
+                if(a<8 || b<8) return 1e30;
+                double sum=0;
+                for(auto p:local) {
+                    double u=(p.x-x)/a,v=(p.y-y)/b,r=std::hypot(u,v);
+                    double normal=std::hypot(u/a,v/b);
+                    double d=normal>1e-9?(r-1)*r/normal:std::min(a,b);
+                    sum+=d*d;
+                }
+                return sum;
+            };
+            double fit=error(cx,cy,rx,ry),step=std::max(rx,ry)*.08;
+            for(int iteration=0;iteration<10;++iteration) {
+                for(int parameter=0;parameter<4;++parameter) for(int sign:{-1,1}) {
+                    double values[]{cx,cy,rx,ry}; values[parameter]+=sign*step;
+                    double next=error(values[0],values[1],values[2],values[3]);
+                    if(next<fit) { fit=next; cx=values[0]; cy=values[1]; rx=values[2]; ry=values[3]; }
+                }
+                step*=.65;
+            }
+            // Require almost one complete turn, with little retracing. This admits a small
+            // closing gap or overshoot but rejects C-shaped arcs, spirals and scribbles.
+            double turn=0,travel=0;
+            for(size_t i=1;i<local.size();++i) {
+                double a=std::atan2((local[i-1].y-cy)/ry,(local[i-1].x-cx)/rx);
+                double b=std::atan2((local[i].y-cy)/ry,(local[i].x-cx)/rx);
+                double delta=std::remainder(b-a,2*3.141592653589793);
+                turn+=delta; travel+=std::abs(delta);
+            }
+            if(std::abs(turn)<5.4 || std::abs(turn)>7.1 || travel-std::abs(turn)>.65) continue;
+            // Near-circular gestures become true circles.
+            bool circle=std::abs(rx-ry)<=std::max(rx,ry)*.12;
+            if(circle) rx=ry=(rx+ry)/2;
+            std::vector<Point> oval;
+            for(int i=0;i<96;++i) {
+                double t=i*2*3.141592653589793/96;
+                oval.push_back(world(cx+rx*std::cos(t),cy+ry*std::sin(t)));
+            }
+            oval.push_back(oval.front()); consider(std::move(oval),circle?ScreenshotShape::Circle:ScreenshotShape::Ellipse);
+        }
+        auto sorted=points;
+        std::sort(sorted.begin(),sorted.end(),[](Point a,Point b){return a.x<b.x || (a.x==b.x && a.y<b.y);});
+        std::vector<Point> hull;
+        for(auto p:sorted) {
+            while(hull.size()>1 && cross(hull[hull.size()-2],hull.back(),p)<=0) hull.pop_back();
+            hull.push_back(p);
+        }
+        size_t lower=hull.size();
+        for(size_t i=sorted.size()-1;i-->0;) {
+            auto p=sorted[i];
+            while(hull.size()>lower && cross(hull[hull.size()-2],hull.back(),p)<=0) hull.pop_back();
+            hull.push_back(p);
+        }
+        hull.pop_back();
+        while(hull.size()>3) {
+            if(hull.size()==4 && bestScore>scale*.035) {
+                // Opposite edges must already be nearly parallel; retain their unequal
+                // lengths and fit a shared direction instead of accepting any quadrilateral.
+                for(size_t i=0;i<2;++i) {
+                    Point a=hull[i],b=hull[i+1],c=hull[(i+2)%4],d=hull[(i+3)%4];
+                    double ab=distance(a,b),cd=distance(c,d);
+                    if(std::min(ab,cd)<16 || std::min(ab,cd)/std::max(ab,cd)>.8) continue;
+                    Point u{(b.x-a.x)/ab,(b.y-a.y)/ab},v{(c.x-d.x)/cd,(c.y-d.y)/cd};
+                    if(u.x*v.x+u.y*v.y<.96) continue;
+                    double norm=std::hypot(u.x+v.x,u.y+v.y);
+                    Point axis{(u.x+v.x)/norm,(u.y+v.y)/norm};
+                    auto along=[&](Point p){return p.x*axis.x+p.y*axis.y;};
+                    auto across=[&](Point p){return -p.x*axis.y+p.y*axis.x;};
+                    double y0=(across(a)+across(b))/2,y1=(across(c)+across(d))/2;
+                    if(std::abs(y1-y0)<20) continue;
+                    auto fit=[&](Point p,double y)->Point {double x=along(p);return {x*axis.x-y*axis.y,x*axis.y+y*axis.x};};
+                    std::vector<Point> candidate{fit(a,y0),fit(b,y0),fit(c,y1),fit(d,y1),fit(a,y0)};
+                    consider(std::move(candidate),ScreenshotShape::Trapezoid);
+                }
+            }
+            size_t remove=0; double area=1e30;
+            for(size_t i=0;i<hull.size();++i) {
+                double a=std::abs(cross(hull[(i+hull.size()-1)%hull.size()],hull[i],hull[(i+1)%hull.size()]));
+                if(a<area) { area=a; remove=i; }
+            }
+            hull.erase(hull.begin()+remove);
+        }
+        if(hull.size()==3) { hull.push_back(hull.front()); consider(hull,ScreenshotShape::Triangle); }
+    }
+    if(best.empty()) {
+        // A small spatial filter suppresses jitter without moving endpoints or flattening broad curves.
+        best=sample(raw,size_t(std::clamp(std::ceil(total/2)+1,5.0,2048.0)));
+        auto original=best;
+        for(size_t i=1;i+1<best.size();++i)
+            best[i]={(original[i-1].x+2*original[i].x+original[i+1].x)/4,
+                     (original[i-1].y+2*original[i].y+original[i+1].y)/4};
+    }
+    std::vector<POINT> result;
+    for(auto p:best) {
+        POINT q{LONG(std::lround(p.x)),LONG(std::lround(p.y))};
+        if(result.empty() || result.back().x!=q.x || result.back().y!=q.y) result.push_back(q);
+    }
+    if(result.size()==input.size() && std::equal(result.begin(),result.end(),input.begin(),
+       [](POINT a,POINT b){return a.x==b.x && a.y==b.y;})) return {};
+    return result;
+}
+}

src/sync.cpp

@@ -0,0 +1,354 @@
+#include "sync.h"
+#include "json.hpp"
+#include <winhttp.h>
+#include <wincred.h>
+#include <set>
+#include <algorithm>
+
+namespace ks
+{
+using Json = nlohmann::json;
+namespace
+{
+constexpr size_t Limit = 4 * 1024 * 1024;
+Bytes bytes(const Json &j) { auto s = j.dump(); return {s.begin(), s.end()}; }
+Json parse(const Bytes &b) { return Json::parse(b.begin(), b.end()); }
+Json configJson(const SyncConfig &c)
+{
+    return {{"enabled", c.enabled}, {"provider", utf8(c.provider)}, {"server", utf8(c.server)},
+        {"mount", utf8(c.mount)}, {"path", utf8(c.path)}, {"authMount", utf8(c.authMount)},
+        {"username", utf8(c.username)}, {"keepLocalLayouts", c.keepLocalLayouts}};
+}
+std::wstring credentialName(const SyncConfig &c)
+{
+    return L"KSwitcher.Sync/" + c.server + L"/" + c.authMount + L"/" + c.username;
+}
+bool safePath(const std::wstring &s)
+{
+    if (s.empty() || s.size() > 512 || s.front() == '/' || s.back() == '/' ||
+        s.find(L"//") != s.npos) return false;
+    return s.find_first_not_of(L"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-/") == s.npos;
+}
+struct HttpHandle
+{
+    HINTERNET h{};
+    ~HttpHandle() { if (h) WinHttpCloseHandle(h); }
+};
+class OpenBao final : public SyncProvider
+{
+    SyncConfig config;
+    SyncTransport transport;
+    std::wstring token;
+    Json response(unsigned status, const Bytes &result, bool missing)
+    {
+        if (result.size() > Limit) throw std::runtime_error("OpenBao response is too large.");
+        if (status == 404 && missing)
+        {
+            auto j = result.empty() ? Json::object() : parse(result);
+            if (j.contains("data") && !j["data"].is_null())
+                throw std::runtime_error("Remote profile is deleted. Restore it in OpenBao first.");
+            return nullptr;
+        }
+        if (status == 401 || status == 403) throw std::runtime_error("OpenBao denied access. Check login and profile policy.");
+        if (status == 400) throw std::runtime_error("OpenBao rejected the write or its version changed. Sync again; check KV v2 configuration.");
+        if (status < 200 || status >= 300) throw std::runtime_error("OpenBao HTTP error " + std::to_string(status) + ".");
+        return result.empty() ? Json::object() : parse(result);
+    }
+    Json request(const wchar_t *method, const std::wstring &path, const Json *body = nullptr, bool missing = false)
+    {
+        if (transport)
+        {
+            auto reply = transport(method, path, token, body ? bytes(*body) : Bytes{});
+            return response(reply.status, reply.body, missing);
+        }
+        URL_COMPONENTS url{sizeof(url)};
+        url.dwHostNameLength = url.dwUrlPathLength = url.dwExtraInfoLength = (DWORD)-1;
+        if (!WinHttpCrackUrl(config.server.c_str(), 0, 0, &url)) throw std::runtime_error("Invalid server URL.");
+        std::wstring host(url.lpszHostName, url.dwHostNameLength);
+        HttpHandle session{WinHttpOpen(L"KSwitcher Sync/1", WINHTTP_ACCESS_TYPE_AUTOMATIC_PROXY,
+            WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0)};
+        if (!session.h || !WinHttpSetTimeouts(session.h, 5000, 5000, 5000, 5000))
+            throw std::runtime_error("Cannot initialize sync connection.");
+        HttpHandle connection{WinHttpConnect(session.h, host.c_str(), url.nPort, 0)};
+        HttpHandle req{connection.h ? WinHttpOpenRequest(connection.h, method, path.c_str(), nullptr,
+            WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_SECURE) : nullptr};
+        DWORD redirects = WINHTTP_OPTION_REDIRECT_POLICY_NEVER;
+        if (!req.h || !WinHttpSetOption(req.h, WINHTTP_OPTION_REDIRECT_POLICY, &redirects, sizeof(redirects)))
+            throw std::runtime_error("Cannot initialize sync request.");
+        std::wstring headers = L"Content-Type: application/json\r\n";
+        if (!token.empty()) headers += L"X-Vault-Token: " + token + L"\r\n";
+        std::string payload = body ? body->dump() : "";
+        bool sent = WinHttpSendRequest(req.h, headers.c_str(), (DWORD)-1,
+            payload.empty() ? WINHTTP_NO_REQUEST_DATA : payload.data(), (DWORD)payload.size(), (DWORD)payload.size(), 0);
+        if (!payload.empty()) SecureZeroMemory(payload.data(), payload.size());
+        if (!sent || !WinHttpReceiveResponse(req.h, nullptr))
+            throw std::runtime_error("OpenBao connection failed. Check network, HTTPS certificate and server address.");
+        DWORD status{}, length = sizeof(status);
+        if (!WinHttpQueryHeaders(req.h, WINHTTP_QUERY_STATUS_CODE | WINHTTP_QUERY_FLAG_NUMBER,
+            WINHTTP_HEADER_NAME_BY_INDEX, &status, &length, WINHTTP_NO_HEADER_INDEX))
+            throw std::runtime_error("Cannot read OpenBao response.");
+        Bytes result;
+        ULONGLONG deadline = GetTickCount64() + 15000;
+        for (;;)
+        {
+            unsigned char chunk[8192]; DWORD received{};
+            if (GetTickCount64() > deadline || !WinHttpReadData(req.h, chunk, sizeof(chunk), &received))
+                throw std::runtime_error("OpenBao response timed out.");
+            if (!received) break;
+            if (result.size() + received > Limit) throw std::runtime_error("OpenBao response is too large.");
+            result.insert(result.end(), chunk, chunk + received);
+        }
+        return response(status, result, missing);
+    }
+  public:
+    explicit OpenBao(const SyncConfig &c, SyncTransport t) : config(c), transport(std::move(t))
+    {
+        validateSyncConfig(c);
+        PCREDENTIALW credential{};
+        if (!CredReadW(credentialName(c).c_str(), CRED_TYPE_GENERIC, 0, &credential))
+            throw std::runtime_error("Sign in: no saved password for this server and user.");
+        std::string password(reinterpret_cast<char *>(credential->CredentialBlob), credential->CredentialBlobSize);
+        SecureZeroMemory(credential->CredentialBlob, credential->CredentialBlobSize);
+        CredFree(credential);
+        Json login{{"password", password}};
+        SecureZeroMemory(password.data(), password.size());
+        Json response;
+        try { response = request(L"POST", L"/v1/auth/" + c.authMount + L"/login/" + c.username, &login); }
+        catch (...) { auto &p = login["password"].get_ref<std::string &>(); SecureZeroMemory(p.data(), p.size()); throw; }
+        auto &p = login["password"].get_ref<std::string &>(); SecureZeroMemory(p.data(), p.size());
+        token = wide(response.at("auth").at("client_token").get<std::string>());
+        if (token.empty() || token.find_first_of(L"\r\n") != token.npos)
+            throw std::runtime_error("Invalid OpenBao authentication response.");
+    }
+    ~OpenBao() override
+    {
+        if (token.empty()) return;
+        // Sessions are scoped to a sync attempt; do not accumulate login tokens.
+        try { request(L"POST", L"/v1/auth/token/revoke-self"); } catch (...) {}
+        SecureZeroMemory(token.data(), token.size() * sizeof(wchar_t));
+    }
+    SyncDocument read() override
+    {
+        auto j = request(L"GET", L"/v1/" + config.mount + L"/data/" + config.path, nullptr, true);
+        if (j.is_null()) return {};
+        const auto &data = j.at("data");
+        if (!data.at("metadata").value("deletion_time", std::string()).empty() ||
+            data.at("metadata").value("destroyed", false))
+            throw std::runtime_error("Remote profile is deleted or destroyed.");
+        auto payload = data.at("data");
+        if (payload.value("syncSchema", 0) != 1 && payload.value("syncSchema", 0) != 2) throw std::runtime_error("Unsupported remote sync format.");
+        return {data.at("metadata").at("version").get<uint64_t>(), bytes(payload.at("settings"))};
+    }
+    uint64_t write(const Bytes &settings, uint64_t revision) override
+    {
+        Json body{{"options", {{"cas", revision}}}, {"data", {{"syncSchema", 2}, {"settings", parse(settings)}}}};
+        auto response = request(L"POST", L"/v1/" + config.mount + L"/data/" + config.path, &body);
+        return response.at("data").at("version").get<uint64_t>();
+    }
+};
+}
+bool syncVisible(const std::filesystem::path &root) { return std::filesystem::exists(root / L"sync.json"); }
+SyncConfig loadSyncConfig(const std::filesystem::path &root)
+{
+    SyncConfig c;
+    if (!syncVisible(root)) return c;
+    auto j = parse(readFile(root / L"sync.json", 16384));
+    c.enabled = j.value("enabled", false);
+    c.keepLocalLayouts = j.value("keepLocalLayouts", false);
+    c.provider = wide(j.value("provider", "openbao"));
+    c.server = wide(j.value("server", ""));
+    c.mount = wide(j.value("mount", "kswitcher"));
+    c.path = wide(j.value("path", "personal/settings"));
+    c.authMount = wide(j.value("authMount", "userpass"));
+    c.username = wide(j.value("username", ""));
+    return c;
+}
+void validateSyncConfig(const SyncConfig &c)
+{
+    if (c.provider != L"openbao") throw std::runtime_error("Unsupported sync provider.");
+    URL_COMPONENTS url{sizeof(url)};
+    url.dwHostNameLength = url.dwUrlPathLength = url.dwExtraInfoLength = url.dwUserNameLength = url.dwPasswordLength = (DWORD)-1;
+    if (c.server.size() > 1024 || !WinHttpCrackUrl(c.server.c_str(), 0, 0, &url) ||
+        url.nScheme != INTERNET_SCHEME_HTTPS || !url.dwHostNameLength || url.dwUserNameLength ||
+        url.dwPasswordLength || url.dwExtraInfoLength ||
+        (url.dwUrlPathLength && std::wstring(url.lpszUrlPath, url.dwUrlPathLength) != L"/"))
+        throw std::runtime_error("Server must be an HTTPS origin, for example https://bao.example.com (no path or credentials).");
+    bool userValid = !c.username.empty() && c.username.size() <= 256 && c.username != L"." && c.username != L".." &&
+        c.username.find_first_not_of(L"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-.@") == c.username.npos;
+    if (!safePath(c.mount) || !safePath(c.path) || !safePath(c.authMount) || !userValid)
+        throw std::runtime_error("Use letters, numbers, underscores and hyphens in paths and login; / is allowed only in paths.");
+    if (credentialName(c).size() > CRED_MAX_GENERIC_TARGET_NAME_LENGTH)
+        throw std::runtime_error("Sync connection name is too long.");
+}
+void saveSyncConfig(const std::filesystem::path &root, const SyncConfig &c)
+{
+    if (c.enabled) validateSyncConfig(c);
+    atomicWrite(root / L"sync.json", bytes(configJson(c)));
+}
+void saveSyncPassword(const SyncConfig &c, const std::wstring &password)
+{
+    validateSyncConfig(c);
+    auto secret = utf8(password);
+    if (secret.empty() || secret.size() > CRED_MAX_CREDENTIAL_BLOB_SIZE) throw std::runtime_error("Password is empty or too long.");
+    auto target = credentialName(c);
+    CREDENTIALW credential{}; credential.Type = CRED_TYPE_GENERIC; credential.TargetName = target.data();
+    credential.UserName = const_cast<wchar_t *>(c.username.c_str());
+    credential.CredentialBlob = reinterpret_cast<BYTE *>(secret.data());
+    credential.CredentialBlobSize = (DWORD)secret.size(); credential.Persist = CRED_PERSIST_LOCAL_MACHINE;
+    bool ok = CredWriteW(&credential, 0) != 0;
+    SecureZeroMemory(secret.data(), secret.size());
+    if (!ok) throw std::runtime_error("Cannot save password in Windows Credential Manager.");
+}
+void forgetSyncPassword(const SyncConfig &c)
+{
+    if (!CredDeleteW(credentialName(c).c_str(), CRED_TYPE_GENERIC, 0) && GetLastError() != ERROR_NOT_FOUND)
+        throw std::runtime_error("Cannot remove saved sync password.");
+}
+std::unique_ptr<SyncProvider> makeSyncProvider(const SyncConfig &c, SyncTransport transport)
+{
+    return std::make_unique<OpenBao>(c, std::move(transport));
+}
+namespace { Json canonicalProfile(Json); }
+Bytes sharedSyncSettings(const Settings &s)
+{
+    auto j = parse(encodeSettings(s));
+    // Windows may enumerate the same installed layouts in a different order on
+    // another PC. Binding order is not user intent (unlike the layout cycle).
+    auto &bindings = j["layoutHotkeys"];
+    std::sort(bindings.begin(), bindings.end(), [](const Json &a, const Json &b) {
+        return a.at("layoutId").get<std::string>() < b.at("layoutId").get<std::string>();
+    });
+    for (auto key : {"startWithSystem", "autostartAsAdministrator", "tesseractPath", "useTesseract",
+        "historyEnabled", "maxItems", "maxTotalMegabytes", "maxImageMegabytes", "writeLog", "preventScreenLock"}) j.erase(key);
+    return bytes(canonicalProfile(j));
+}
+Settings restoreSyncSettings(const Bytes &shared, const Settings &local, const std::vector<Layout> &layouts, bool keepLocalLayouts)
+{
+    auto j = parse(shared), original = parse(encodeSettings(local));
+    if (!j.contains("snippetTombstones")) j["snippetTombstones"] = Json::array();
+    if (!j.contains("autoCorrectReplace")) j["autoCorrectReplace"] = false;
+    if (!j.contains("autoCorrectTypos")) j["autoCorrectTypos"] = false;
+    if (!j.contains("autoCorrectReplacements")) j["autoCorrectReplacements"] = Json::object();
+    auto allowed = parse(sharedSyncSettings(local));
+    if (!j.is_object() || j.value("format", "") != "kswitcher-settings" || j.value("schemaVersion", 0) != 1)
+        throw std::runtime_error("Unsupported synchronized settings format.");
+    for (auto it = j.begin(); it != j.end(); ++it)
+        if (!allowed.contains(it.key())) throw std::runtime_error("Remote profile contains unsupported or local-only fields.");
+    if (j.size() != allowed.size()) throw std::runtime_error("Remote profile is incomplete.");
+    std::set<std::string> installed;
+    for (const auto &layout : layouts) installed.insert(utf8(layout.id));
+    std::set<std::string> missing;
+    for (const auto &id : j.at("layouts"))
+        if (!installed.contains(id.get<std::string>())) missing.insert(id.get<std::string>());
+    for (const auto &key : j.at("layoutHotkeys"))
+        if (!installed.contains(key.at("layoutId").get<std::string>())) missing.insert(key.at("layoutId").get<std::string>());
+    if (!keepLocalLayouts && !missing.empty())
+    {
+        std::wstring message = L"Missing keyboard layouts on this PC: ";
+        for (const auto &id : missing)
+        {
+            auto code = id.starts_with("win:") ? id.substr(4) : id;
+            wchar_t language[128]{};
+            if (code.size() == 8 && code.find_first_not_of("0123456789abcdefABCDEF") == code.npos)
+                GetLocaleInfoW(MAKELCID(LOWORD(std::stoul(code, nullptr, 16)), SORT_DEFAULT), LOCALE_SENGLISHLANGUAGENAME,
+                               language, 128);
+            if (message.back() != L' ') message += L"; ";
+            message += (language[0] ? std::wstring(language) : L"Unknown layout") + L" [" + wide(id) + L"]";
+        }
+        message += L". Install these exact layouts, or enable 'Keep this PC's layouts' below and sync other settings.";
+        throw std::runtime_error(utf8(message));
+    }
+    if (keepLocalLayouts)
+        for (auto key : {"layouts", "layoutHotkeys"}) j[key] = original.at(key);
+    original.update(j);
+    return decodeSettings(bytes(original), layouts);
+}
+#include "sync_merge.inl"
+SyncResult synchronize(SyncProvider &provider, const Bytes &base, const Bytes &local, SyncAction action,
+    const std::function<void(const Bytes &)> &validate, const std::vector<SyncChoice> &choices, bool keepLocalLayouts)
+{
+    if (local.size() > Limit) throw std::runtime_error("Settings exceed the sync size limit.");
+    if (validate) validate(local);
+    auto remote = provider.read();
+    if (!remote.revision)
+    {
+        if (action != SyncAction::Upload) throw std::runtime_error("No remote profile. Choose Upload local to create it.");
+        return {true, local, provider.write(local, 0), L"Uploaded new profile."};
+    }
+    if (validate && action != SyncAction::Upload) validate(remote.settings);
+    auto mergeLocal = local, mergeBase = base;
+    if (keepLocalLayouts)
+    {
+        // Never upload a locally filtered projection over another PC's layout setup.
+        const auto remoteJson = parse(remote.settings);
+        auto preserve = [&](const Bytes &profile)
+        {
+            auto j = parse(profile);
+            for (auto key : {"layouts", "layoutHotkeys"}) j[key] = remoteJson.at(key);
+            return bytes(j);
+        };
+        mergeLocal = preserve(local);
+        if (!base.empty()) mergeBase = preserve(base);
+    }
+    SyncMerge merged;
+    if (action == SyncAction::Automatic) merged = mergeSyncProfile(mergeBase, mergeLocal, remote.settings, choices);
+    else
+    {
+        auto selected = bytes(normalizeProfile(parse(action == SyncAction::Download ? remote.settings : mergeLocal)));
+        merged = {selected, selected, selected, {}};
+    }
+    if (validate) { validate(merged.local); validate(merged.remote); }
+    auto revision = remote.revision;
+    if (parse(merged.remote) != parse(remote.settings) && action != SyncAction::Download) revision = provider.write(merged.remote, revision);
+    return {true, merged.local, revision,
+        merged.conflicts.empty() ? L"Synchronized. Server version " + std::to_wstring(revision) + L"." :
+            L"Other changes synchronized. Resolve " + std::to_wstring(merged.conflicts.size()) + L" conflicting setting(s).",
+        merged.base, merged.conflicts};
+}
+Bytes encodeSyncConflicts(const std::vector<SyncConflict> &conflicts)
+{
+    Json j = Json::array();
+    for (const auto &c : conflicts) j.push_back({{"key", c.key}, {"label", utf8(c.label)}, {"local", parse(c.local)}, {"remote", parse(c.remote)}});
+    return bytes(j);
+}
+std::vector<SyncConflict> decodeSyncConflicts(const Bytes &data)
+{
+    std::vector<SyncConflict> result;
+    for (const auto &c : parse(data)) result.push_back({c.at("key"), wide(c.at("label").get<std::string>()), bytes(c.at("local")), bytes(c.at("remote"))});
+    return result;
+}
+Bytes encodeSyncChoices(const std::vector<SyncChoice> &choices)
+{
+    Json j = Json::array();
+    for (const auto &c : choices) j.push_back({{"conflict", parse(encodeSyncConflicts({c.conflict})).at(0)}, {"useLocal", c.useLocal}});
+    return bytes(j);
+}
+std::vector<SyncChoice> decodeSyncChoices(const Bytes &data)
+{
+    auto j = parse(data);
+    if (!j.is_array() || j.size() > 10000) throw std::runtime_error("Invalid conflict choices.");
+    std::vector<SyncChoice> result;
+    for (const auto &c : j) result.push_back({decodeSyncConflicts(bytes(Json::array({c.at("conflict")}))).at(0), c.at("useLocal").get<bool>()});
+    return result;
+}
+std::wstring syncValueText(const Bytes &data)
+{
+    auto j = parse(data);
+    if (j.is_null()) return L"(not present)";
+    if (tombstone(j)) return L"(deleted)";
+    return wide(j.is_string() ? j.get<std::string>() : j.dump(2));
+}
+Bytes loadSyncBase(const std::filesystem::path &root, const SyncConfig &c)
+{
+    auto path = root / L"sync-base.bin";
+    if (!std::filesystem::exists(path)) return {};
+    auto j = parse(unprotect(readFile(path, Limit + 65536)));
+    auto connection = j.at("connection");
+    if (!connection.contains("keepLocalLayouts")) connection["keepLocalLayouts"] = false;
+    return connection == configJson(c) ? bytes(j.at("settings")) : Bytes{};
+}
+void saveSyncBase(const std::filesystem::path &root, const SyncConfig &c, const Bytes &base)
+{
+    atomicWrite(root / L"sync-base.bin", protect(bytes({{"connection", configJson(c)}, {"settings", parse(base)}})));
+}
+}

src/sync.h

@@ -0,0 +1,72 @@
+#pragma once
+#include "storage.h"
+#include <memory>
+
+namespace ks
+{
+struct SyncConfig
+{
+    bool enabled{};
+    bool keepLocalLayouts{};
+    std::wstring provider = L"openbao", server, mount = L"kswitcher",
+        path = L"personal/settings", authMount = L"userpass", username;
+    bool operator==(const SyncConfig &) const = default;
+};
+bool syncVisible(const std::filesystem::path &);
+SyncConfig loadSyncConfig(const std::filesystem::path &);
+void saveSyncConfig(const std::filesystem::path &, const SyncConfig &);
+void validateSyncConfig(const SyncConfig &);
+void saveSyncPassword(const SyncConfig &, const std::wstring &);
+void forgetSyncPassword(const SyncConfig &);
+struct SyncDocument { uint64_t revision{}; Bytes settings; };
+class SyncProvider
+{
+  public:
+    virtual ~SyncProvider() = default;
+    virtual SyncDocument read() = 0;
+    virtual uint64_t write(const Bytes &, uint64_t expectedRevision) = 0;
+};
+struct SyncHttpResponse { unsigned status{}; Bytes body; };
+using SyncTransport = std::function<SyncHttpResponse(const std::wstring &method, const std::wstring &path,
+    const std::wstring &token, const Bytes &body)>;
+// An injectable transport permits protocol regression tests without a live vault.
+std::unique_ptr<SyncProvider> makeSyncProvider(const SyncConfig &, SyncTransport transport = {});
+inline constexpr ULONGLONG SyncIntervalMs = 10 * 60 * 1000;
+struct SyncConflict
+{
+    std::string key;
+    std::wstring label;
+    Bytes local, remote;
+};
+struct SyncChoice { SyncConflict conflict; bool useLocal{}; };
+Bytes encodeSyncConflicts(const std::vector<SyncConflict> &);
+std::vector<SyncConflict> decodeSyncConflicts(const Bytes &);
+Bytes encodeSyncChoices(const std::vector<SyncChoice> &);
+std::vector<SyncChoice> decodeSyncChoices(const Bytes &);
+std::wstring syncValueText(const Bytes &);
+struct SyncMerge
+{
+    Bytes local, remote, base;
+    std::vector<SyncConflict> conflicts;
+};
+SyncMerge mergeSyncProfile(const Bytes &base, const Bytes &local, const Bytes &remote,
+    const std::vector<SyncChoice> &choices = {});
+Bytes mergeSyncSettings(const Bytes &base, const Bytes &local, const Bytes &remote);
+Bytes sharedSyncSettings(const Settings &);
+Settings restoreSyncSettings(const Bytes &, const Settings &, const std::vector<Layout> &, bool keepLocalLayouts = false);
+enum class SyncAction { Automatic, Download, Upload };
+struct SyncResult
+{
+    bool success{};
+    Bytes settings;
+    uint64_t revision{};
+    std::wstring status;
+    Bytes base;
+    std::vector<SyncConflict> conflicts;
+};
+SyncResult synchronize(SyncProvider &, const Bytes &base, const Bytes &local, SyncAction,
+    const std::function<void(const Bytes &)> &validate = {}, const std::vector<SyncChoice> &choices = {},
+    bool keepLocalLayouts = false);
+Bytes loadSyncBase(const std::filesystem::path &, const SyncConfig &);
+void saveSyncBase(const std::filesystem::path &, const SyncConfig &, const Bytes &);
+}

src/sync_merge.inl

@@ -0,0 +1,201 @@
+// Three-way merge operates on individual values; unresolved values retain their
+// respective local/remote versions and their old common ancestor.
+namespace
+{
+Json normalizeProfile(Json j)
+{
+    if (!j.contains("autoCorrectReplace")) j["autoCorrectReplace"] = false;
+    if (!j.contains("autoCorrectTypos")) j["autoCorrectTypos"] = false;
+    if (!j.contains("autoCorrectReplacements")) j["autoCorrectReplacements"] = Json::object();
+    if (!j.contains("snippetTombstones")) j["snippetTombstones"] = Json::array();
+    for (auto &sn : j.at("snippets"))
+        if (!sn.contains("id")) sn["id"] = utf8(snippetId({wide(sn.at("trigger").get<std::string>()), L""}));
+    return j;
+}
+Json treeProfile(const Json &source)
+{
+    auto j = normalizeProfile(source);
+    Json items = Json::object();
+    for (const auto &sn : j.at("snippets"))
+    {
+        auto id = sn.at("id").get<std::string>();
+        if (items.contains(id)) throw std::runtime_error("Duplicate snippet ID.");
+        items[id] = sn;
+    }
+    for (const auto &id : j.at("snippetTombstones"))
+    {
+        auto key = id.get<std::string>();
+        if (items.contains(key)) throw std::runtime_error("Duplicate or deleted snippet ID.");
+        items[key] = {{"$deleted", true}};
+    }
+    j["snippets"] = items;
+    j.erase("snippetTombstones");
+    items = Json::object();
+    for (const auto &binding : j.at("layoutHotkeys")) items[binding.at("layoutId").get<std::string>()] = binding.at("hotkey");
+    j["layoutHotkeys"] = items;
+    for (auto key : {"excludedApps", "autoCorrectNever", "autoCorrectExcludedApps"})
+    {
+        items = Json::object();
+        for (const auto &item : j.at(key)) items[item.get<std::string>()] = true;
+        j[key] = items;
+    }
+    for (auto &language : j.at("autoCorrectWords").items())
+    {
+        items = Json::object();
+        for (const auto &word : language.value()) items[word.get<std::string>()] = true;
+        language.value() = items;
+    }
+    return j;
+}
+Json flatProfile(Json j)
+{
+    auto &replacements = j["autoCorrectReplacements"];
+    for (auto it = replacements.begin(); it != replacements.end();)
+        if (it.value().is_null()) it = replacements.erase(it);
+        else ++it;
+    Json snippets = Json::array(), deleted = Json::array();
+    for (const auto &[id, item] : j.at("snippets").items())
+    {
+        if (item.is_null()) continue;
+        if (item.value("$deleted", false)) deleted.push_back(id);
+        else snippets.push_back(item);
+    }
+    j["snippets"] = snippets; j["snippetTombstones"] = deleted;
+    Json bindings = Json::array();
+    for (const auto &[id, hotkey] : j.at("layoutHotkeys").items())
+        if (!hotkey.is_null()) bindings.push_back({{"layoutId", id}, {"hotkey", hotkey}});
+    j["layoutHotkeys"] = bindings;
+    for (auto key : {"excludedApps", "autoCorrectNever", "autoCorrectExcludedApps"})
+    {
+        Json list = Json::array();
+        for (const auto &[item, present] : j.at(key).items()) if (present == true) list.push_back(item);
+        j[key] = list;
+    }
+    for (auto &language : j.at("autoCorrectWords").items())
+    {
+        Json list = Json::array();
+        if (language.value().is_object())
+            for (const auto &[word, present] : language.value().items()) if (present == true) list.push_back(word);
+        language.value() = list;
+    }
+    return j;
+}
+std::string pointerKey(const std::string &s)
+{
+    std::string out;
+    for (char c : s) out += c == '~' ? "~0" : c == '/' ? "~1" : std::string(1, c);
+    return out;
+}
+Json canonicalProfile(Json j) { return flatProfile(treeProfile(j)); }
+std::wstring fieldLabel(const std::string &key)
+{
+    static const std::map<std::string, std::wstring> labels{
+        {"toggleHotkey", L"Next layout shortcut"}, {"caseHotkey", L"Change case shortcut"},
+        {"translitHotkey", L"Transliteration shortcut"}, {"undoHotkey", L"Undo shortcut"},
+        {"clipboardHotkey", L"Clipboard shortcut"}, {"screenshotHotkey", L"Screenshot shortcut"},
+        {"layouts", L"Layout cycle order"}, {"layoutHotkeys", L"Layout shortcuts"},
+        {"convertLastWord", L"Convert recent word"}, {"switchSystemLayout", L"Switch system layout"},
+        {"autoCorrectMinLength", L"Minimum word length"}, {"autoCorrectMaxRank", L"Maximum word rank"},
+        {"autoCorrectLayout", L"Automatic layout correction"}, {"autoCorrectLanguages", L"Dictionary languages"},
+        {"autoCorrectReplace", L"Custom automatic replacements"}, {"autoCorrectTypos", L"Dictionary typo correction"},
+        {"autoCorrectReplacements", L"Replacement pairs"},
+        {"autoCorrectPrefixChars", L"Punctuation before words"}, {"autoCorrectSuffixChars", L"Punctuation after words"},
+        {"screenshotAutoOpenEditor", L"Open screenshot editor"}, {"tesseractLanguages", L"OCR languages"},
+        {"trigger", L"Trigger"}, {"text", L"Text"}};
+    auto it = labels.find(key); return it == labels.end() ? wide(key) : it->second;
+}
+struct MergeNode { Json local, remote, base; };
+bool tombstone(const Json &j) { return j.is_object() && j.value("$deleted", false); }
+MergeNode mergeNode(const Json &b, const Json &l, const Json &r, const std::string &path,
+    const std::wstring &label, const std::vector<SyncChoice> &choices, std::vector<SyncConflict> &conflicts,
+    const std::set<std::string> &forced)
+{
+    if (l == r) return {l, l, l};
+    for (const auto &choice : choices)
+        if (choice.conflict.key == path && parse(choice.conflict.local) == l && parse(choice.conflict.remote) == r)
+        {
+            auto selected = choice.useLocal ? l : r;
+            if (selected.is_null() && path.starts_with("/snippets/") && path.find('/', 10) == std::string::npos)
+                selected = {{"$deleted", true}};
+            return {selected, selected, selected};
+        }
+    if (forced.contains(path))
+    {
+        conflicts.push_back({path, label + L" (duplicate trigger or shortcut)", bytes(l), bytes(r)});
+        return {l, r, b};
+    }
+    bool forcedChild = std::any_of(forced.begin(), forced.end(), [&](const std::string &key) { return key.starts_with(path + "/"); });
+    if (!forcedChild && l == b) return {r, r, r};
+    if (!forcedChild && r == b) return {l, l, l};
+    if (l.is_object() && r.is_object() && (b.is_object() || b.is_null()) && !tombstone(l) && !tombstone(r) && !tombstone(b))
+    {
+        MergeNode out{Json::object(), Json::object(), Json::object()};
+        std::set<std::string> keys;
+        for (const auto *j : {&b, &l, &r}) if (j->is_object()) for (auto it = j->begin(); it != j->end(); ++it) keys.insert(it.key());
+        for (const auto &key : keys)
+        {
+            auto get = [&](const Json &j) { return j.is_object() && j.contains(key) ? j.at(key) : Json(); };
+            auto childLabel = label.empty() ? fieldLabel(key) : label + L" / " + fieldLabel(key);
+            if (path == "/snippets")
+            {
+                auto item = get(l); if (item.is_null() || tombstone(item)) item = get(r);
+                childLabel = L"Snippet: " + wide(item.is_object() ? item.value("trigger", key) : key);
+            }
+            auto child = mergeNode(get(b), get(l), get(r), path + "/" + pointerKey(key), childLabel, choices, conflicts, forced);
+            // Keep nulls in the ancestor so deletion conflicts survive restarts.
+            out.local[key] = child.local; out.remote[key] = child.remote; out.base[key] = child.base;
+        }
+        return out;
+    }
+    conflicts.push_back({path, label, bytes(l), bytes(r)});
+    return {l, r, b};
+}
+void collisionPaths(const Json &j, std::set<std::string> &paths)
+{
+    std::map<std::wstring, std::string> triggers;
+    for (const auto &[id, sn] : j.at("snippets").items())
+    {
+        if (sn.is_null() || tombstone(sn)) continue;
+        auto path = "/snippets/" + pointerKey(id);
+        auto key = lower(wide(sn.at("trigger").get<std::string>()));
+        auto [it, inserted] = triggers.emplace(key, path);
+        if (!inserted) { paths.insert(path); paths.insert(it->second); }
+    }
+    std::map<std::pair<UINT, UINT>, std::string> shortcuts;
+    auto add = [&](const Json &text, const std::string &path) {
+        if (!text.is_string()) return;
+        auto hotkey = Hotkey::parse(wide(text.get<std::string>()));
+        if (!hotkey || !hotkey->key) return;
+        auto [it, inserted] = shortcuts.emplace(std::make_pair(hotkey->modifiers, hotkey->key), path);
+        if (!inserted) { paths.insert(path); paths.insert(it->second); }
+    };
+    for (const auto *key : {"toggleHotkey", "caseHotkey", "translitHotkey", "undoHotkey", "clipboardHotkey", "screenshotHotkey"}) add(j.at(key), std::string("/") + key);
+    for (const auto &[id, key] : j.at("layoutHotkeys").items()) add(key, "/layoutHotkeys/" + pointerKey(id));
+}
+}
+SyncMerge mergeSyncProfile(const Bytes &base, const Bytes &local, const Bytes &remote, const std::vector<SyncChoice> &choices)
+{
+    auto l = treeProfile(parse(local)), r = treeProfile(parse(remote));
+    // With no common history, union independent entries; differing scalar values
+    // remain on their respective devices until the user resolves the conflict.
+    auto b = base.empty() ? Json::object() : treeProfile(parse(base));
+    SyncMerge result;
+    auto merged = mergeNode(b, l, r, "", L"", choices, result.conflicts, {});
+    std::set<std::string> collisions;
+    collisionPaths(merged.local, collisions); collisionPaths(merged.remote, collisions);
+    if (!collisions.empty())
+    {
+        result.conflicts.clear();
+        merged = mergeNode(b, l, r, "", L"", choices, result.conflicts, collisions);
+    }
+    result.local = bytes(flatProfile(merged.local));
+    result.remote = bytes(flatProfile(merged.remote));
+    result.base = bytes(flatProfile(merged.base));
+    return result;
+}
+Bytes mergeSyncSettings(const Bytes &base, const Bytes &local, const Bytes &remote)
+{
+    auto result = mergeSyncProfile(base, local, remote);
+    if (!result.conflicts.empty()) throw std::runtime_error("Conflicting setting: " + result.conflicts.front().key);
+    return result.local;
+}

src/ui.cpp

@@ -83,7 +83,7 @@ void arrangeWindow(HWND w)
     {
         int id = GetDlgCtrlID(child);
         RECT next{scale(w, r.left) - layout->x,
-                  scale(w, r.top) - layout->y + (id >= 110 && id <= 114 ? extraHeight : 0)};
+                  scale(w, r.top) - layout->y + ((id >= 110 && id <= 114) || id == 116 ? extraHeight : 0)};
         next.right = next.left + scale(w, r.right - r.left) + (id == 101 || id == 102 ? extraWidth : 0);
         next.bottom = next.top + scale(w, r.bottom - r.top) + (id == 102 ? extraHeight : 0);
         if (child == layout->stretch)
@@ -493,7 +493,7 @@ bool selectedImage(HWND w, HistoryView *v)
 }
 void updateHistoryActions(HWND w, HistoryView *v)
 {
-    SetDlgItemTextW(w,114,selectedImage(w,v)?L"Edit image":L"Open item");
+    SetDlgItemTextW(w,114,selectedImage(w,v)?L"&Edit image":L"&Open item");
 }
 std::wstring selected(HWND w, HistoryView *v)
 {
@@ -730,6 +730,13 @@ LRESULT CALLBACK historyProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             }
             if (id == 102 && HIWORD(wp) == LBN_DBLCLK)
                 id = 110;
+            if (id == 116)
+            {
+                if (MessageBoxW(w, L"Delete all clipboard history, including pinned items? This also deletes items hidden by the current search.",
+                                L"Clear history", MB_YESNO | MB_ICONWARNING | MB_DEFBUTTON2) == IDYES)
+                    v->app->clearHistory();
+                return 0;
+            }
             auto entry = selected(w, v);
             if (id == 110 || id == 111)
             {
@@ -854,12 +861,12 @@ LRESULT CALLBACK historyProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 p={row.left,row.top}; ClientToScreen(list,&p);
             }
             HMENU menu = CreatePopupMenu();
-            AppendMenuW(menu, MF_STRING, 110, L"Paste");
+            AppendMenuW(menu, MF_STRING, 110, L"&Paste");
-            AppendMenuW(menu, MF_STRING, 111, L"Paste plain text");
+            AppendMenuW(menu, MF_STRING, 111, L"Paste plain &text");
-            AppendMenuW(menu, MF_STRING, 112, L"Pin / unpin");
+            AppendMenuW(menu, MF_STRING, 112, L"P&in / unpin");
-            AppendMenuW(menu, MF_STRING, 113, L"Delete");
+            AppendMenuW(menu, MF_STRING, 113, L"&Delete");
-            AppendMenuW(menu, MF_STRING, 114, selectedImage(w,v)?L"Edit image in screenshot editor":L"Open full item");
+            AppendMenuW(menu, MF_STRING, 114, selectedImage(w,v)?L"&Edit image in screenshot editor":L"&Open full item");
-            AppendMenuW(menu, MF_STRING, 115, L"Copy text from image (OCR)");
+            AppendMenuW(menu, MF_STRING, 115, L"&Copy text from image (OCR)");
             int cmd = TrackPopupMenu(menu, TPM_RETURNCMD, p.x, p.y, 0, w, nullptr);
             DestroyMenu(menu);
             if (cmd)
@@ -1112,6 +1119,25 @@ LRESULT CALLBACK autoOptionsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             draft.autoExcluded = parseCommaList(value(w, 404));
             draft.autoPrefixChars = value(w, 408);
             draft.autoSuffixChars = value(w, 409);
+            draft.autoReplace = checked(w, 414);
+            draft.autoTypos = checked(w, 415);
+            draft.autoReplacements.clear();
+            std::wistringstream replacements(lower(value(w, 416)));
+            std::wstring line;
+            auto trim = [](std::wstring text)
+            {
+                auto first = text.find_first_not_of(L" \t\r\n");
+                return first == text.npos ? std::wstring{} : text.substr(first, text.find_last_not_of(L" \t\r\n") - first + 1);
+            };
+            while (std::getline(replacements, line))
+            {
+                if (trim(line).empty()) continue;
+                auto equals = line.find(L'=');
+                if (equals == line.npos)
+                    throw std::runtime_error("Enter one replacement per line: typo=correction");
+                if (!draft.autoReplacements.emplace(trim(line.substr(0, equals)), trim(line.substr(equals + 1))).second)
+                    throw std::runtime_error("Each replacement typo must occur only once");
+            }
             if (draft.autoLanguages.size() < 2)
                 throw std::runtime_error("Select at least two languages");
             validateSettings(draft);
@@ -1123,6 +1149,9 @@ LRESULT CALLBACK autoOptionsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             view->settings->draft.autoMinLength = draft.autoMinLength;
             view->settings->draft.autoPrefixChars = draft.autoPrefixChars;
             view->settings->draft.autoSuffixChars = draft.autoSuffixChars;
+            view->settings->draft.autoReplace = draft.autoReplace;
+            view->settings->draft.autoTypos = draft.autoTypos;
+            view->settings->draft.autoReplacements = std::move(draft.autoReplacements);
             DestroyWindow(w);
         }
         catch (const std::exception &e)
@@ -1153,15 +1182,15 @@ LRESULT CALLBACK autoOptionsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
 }
 void showAutoOptions(HWND parent, SettingsView *v)
 {
-    HWND w = makeWindow(*v->app, L"KSwitcher.AutoOptions", L"Automatic layout correction", autoOptionsProc,
+    HWND w = makeWindow(*v->app, L"KSwitcher.AutoOptions", L"Automatic correction", autoOptionsProc,
-                        560, 680);
+                        560, 880);
     windowLayoutState(w)->autoOptions = true;
     SetWindowLongPtrW(w, GWLP_HWNDPARENT, (LONG_PTR)parent);
     SetWindowLongPtrW(w, GWLP_USERDATA, (LONG_PTR) new AutoOptionsView{parent, v});
     label(w, L"Offline dictionaries (only layouts in your cycle are used)", 18, 16, 525);
-    checkbox(w, L"English", 401, 18, 48, 150);
+    checkbox(w, L"&English", 401, 18, 48, 150);
-    checkbox(w, L"Ukrainian", 402, 188, 48, 150);
+    checkbox(w, L"&Ukrainian", 402, 188, 48, 150);
-    checkbox(w, L"Russian", 403, 358, 48, 150);
+    checkbox(w, L"&Russian", 403, 358, 48, 150);
     for (auto &lang : v->draft.autoLanguages)
         check(w, lang == L"en" ? 401 : lang == L"uk" ? 402 : 403, true);
     label(w, L"Excluded applications (process names, comma-separated)", 18, 94, 525);
@@ -1174,7 +1203,7 @@ void showAutoOptions(HWND parent, SettingsView *v)
     for (auto [id, language] : {std::pair{411, L"en"}, {412, L"uk"}, {413, L"ru"}})
     {
         int x = 18 + (id - 411) * 178;
-        label(w, id == 411 ? L"English" : id == 412 ? L"Ukrainian" : L"Russian", x, 302, 168);
+        label(w, id == 411 ? L"En&glish" : id == 412 ? L"U&krainian" : L"Ru&ssian", x, 302, 168);
         edit(w, id, x, 328, 168, 56, ES_MULTILINE | WS_VSCROLL | ES_AUTOVSCROLL | ES_WANTRETURN);
         auto words = v->draft.autoWords.find(language);
         if (words != v->draft.autoWords.end()) value(w, id, commaList(words->second));
@@ -1192,10 +1221,20 @@ void showAutoOptions(HWND parent, SettingsView *v)
     value(w, 408, v->draft.autoPrefixChars);
     value(w, 409, v->draft.autoSuffixChars);
     label(w, L"Enter punctuation without spaces or separators. These characters are kept.", 18, 530, 525);
-    button(w, L"Open dictionary folder", 407, 18, 562, 220);
+    checkbox(w, L"Use custom &replacements (take priority over dictionaries)", 414, 18, 562, 524);
-    label(w, L"After editing files, click OK here, then Save in Settings to reload.", 18, 600, 525);
+    check(w, 414, v->draft.autoReplace);
-    button(w, L"OK", IDOK, 326, 632, 100);
+    label(w, L"One pair per line: typo=correction (same language, letters only)", 18, 592, 525);
-    button(w, L"Cancel", IDCANCEL, 440, 632, 100);
+    edit(w, 416, 18, 618, 524, 70, ES_MULTILINE | WS_VSCROLL | ES_AUTOVSCROLL | ES_WANTRETURN);
+    std::wstring pairs;
+    for (const auto &[from, to] : v->draft.autoReplacements) pairs += from + L"=" + to + L"\r\n";
+    value(w, 416, pairs);
+    checkbox(w, L"Correct spelling &typos using dictionaries (experimental)", 415, 18, 700, 524);
+    check(w, 415, v->draft.autoTypos);
+    label(w, L"Single edits, 4+ letters; ambiguous words are left unchanged.", 18, 730, 525);
+    button(w, L"Open dictionary &folder", 407, 18, 762, 220);
+    label(w, L"Click OK, then Save in Settings. Enable automatic correction there.", 18, 800, 525);
+    button(w, L"&OK", IDOK, 326, 832, 100);
+    button(w, L"&Cancel", IDCANCEL, 440, 832, 100);
     RECT initial{};
     GetWindowRect(w, &initial);
     initial.right += scale(w, 200);
@@ -1278,26 +1317,27 @@ void showOcrOptions(HWND parent, SettingsView *v)
     SetWindowLongPtrW(w, GWLP_HWNDPARENT, (LONG_PTR)parent);
     SetWindowLongPtrW(w, GWLP_USERDATA, (LONG_PTR)new OcrOptionsView{parent, v});
     label(w, L"Windows OCR is used by default. Recognition stays on this computer.", 18, 16, 600);
-    checkbox(w, L"Use optional Tesseract 5 instead of Windows OCR", 501, 18, 48, 600);
+    checkbox(w, L"&Use optional Tesseract 5 instead of Windows OCR", 501, 18, 48, 600);
     check(w, 501, v->draft.useTesseract);
     label(w, L"Tesseract executable (blank = detect installed location)", 18, 90, 600);
     edit(w, 502, 18, 118, 484);
     value(w, 502, v->draft.tesseractPath);
-    button(w, L"Browse…", 504, 514, 117, 106);
+    button(w, L"&Browse…", 504, 514, 117, 106);
     label(w, L"Languages used together (for example ukr+eng+rus)", 18, 160, 600);
     edit(w, 503, 18, 188, 602);
     value(w, 503, v->draft.tesseractLanguages);
-    button(w, L"Check installation", 505, 18, 228, 180);
+    button(w, L"Check &installation", 505, 18, 228, 180);
     control(w, L"STATIC", L"", 0, 506, 212, 232, 408, 24);
-    button(w, L"Download Tesseract…", 507, 18, 266, 180);
+    button(w, L"&Download Tesseract…", 507, 18, 266, 180);
     label(w, L"Opens the Windows installer page in your browser.", 212, 270, 408);
     label(w, L"Changing the engine or languages reprocesses saved images in the background.", 18, 314, 602);
     label(w, L"Click OK here, then Save in Settings to apply. No downloads are automatic.", 18, 344, 602);
-    button(w, L"OK", IDOK, 406, 390, 100);
+    button(w, L"&OK", IDOK, 406, 390, 100);
-    button(w, L"Cancel", IDCANCEL, 520, 390, 100);
+    button(w, L"&Cancel", IDCANCEL, 520, 390, 100);
     EnableWindow(parent, FALSE);
     showRequestedWindow(w); SetForegroundWindow(w);
 }
+#include "ui_sync.inl"
 LRESULT CALLBACK settingsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
 {
     if (msg == WM_DPICHANGED)
@@ -1334,6 +1374,7 @@ LRESULT CALLBACK settingsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 return 0;
             }
             if (id == 257) { showOcrOptions(w, v); return 0; }
+            if (id == 258) { showSyncOptions(w, *v->app); return 0; }
             if (id == 230)
             {
                 collectLayout(w, v);
@@ -1455,7 +1496,10 @@ void collectSnippet(HWND w, SnippetView *v)
 {
     if (v->selection >= 0 && v->selection < (int)v->snippets.size())
     {
-        v->snippets[v->selection] = {value(w, 302), value(w, 303)};
+        auto &snippet = v->snippets[v->selection];
+        if (snippet.id.empty()) snippet.id = snippetId(snippet);
+        snippet.trigger = value(w, 302);
+        snippet.text = value(w, 303);
     }
 }
 LRESULT CALLBACK snippetProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
@@ -1492,7 +1536,7 @@ LRESULT CALLBACK snippetProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             if (id == 310)
             {
                 collectSnippet(w, v);
-                v->snippets.push_back({L";new", L""});
+                v->snippets.push_back({L";new", L"", newSnippetId()});
                 v->selection = (int)v->snippets.size() - 1;
                 fillSnippets(w, v);
                 SetFocus(GetDlgItem(w, 302));
@@ -1601,18 +1645,19 @@ void showHistory(App &app, bool visible)
         app.historyWindow = w;
         windowLayoutState(w)->history = true;
         ((HistoryView *)GetWindowLongPtrW(w, GWLP_USERDATA))->rich = createRichText(w, 105, false);
-        label(w, L"Search clipboard history", 16, 12, 500);
+        label(w, L"&Search clipboard history", 16, 12, 500);
         edit(w, 101, 16, 38, 728);
         auto list = control(w, L"LISTBOX", L"",
                             WS_TABSTOP | WS_VSCROLL | LBS_NOTIFY | LBS_NOINTEGRALHEIGHT | WS_BORDER |
                                 LBS_OWNERDRAWFIXED | LBS_HASSTRINGS,
                             102, 16, 76, 728, 360);
         SendMessageW(list, LB_SETITEMHEIGHT, 0, scale(w, 88));
-        button(w, L"Paste", 110, 16, 452, 90);
+        button(w, L"&Paste", 110, 16, 452, 90);
-        button(w, L"Plain text", 111, 114, 452, 100);
+        button(w, L"Plain &text", 111, 114, 452, 100);
-        button(w, L"Pin / unpin", 112, 222, 452, 110);
+        button(w, L"P&in / unpin", 112, 222, 452, 110);
-        button(w, L"Delete", 113, 340, 452, 90);
+        button(w, L"&Delete", 113, 340, 452, 90);
-        button(w, L"Open item", 114, 438, 452, 100);
+        button(w, L"&Open item", 114, 438, 452, 100);
+        button(w, L"Clear &history…", 116, 546, 452, 150);
         SetWindowSubclass(list, historyKey, 1, (DWORD_PTR)w);
         SetWindowSubclass(GetDlgItem(w, 101), historyKey, 1, (DWORD_PTR)w);
     }
@@ -1651,13 +1696,13 @@ void showSettings(App &app, bool visible)
     HWND w = makeWindow(app, L"KSwitcher.Settings", L"KSwitcher settings", settingsProc, 780, 660, 0, false);
     app.settingsWindow = w;
     label(w, L"Text conversion", 18, 16);
-    checkbox(w, L"Convert recently typed text when nothing is selected", 201, 18, 43, 390);
+    checkbox(w, L"Con&vert recently typed text when nothing is selected", 201, 18, 43, 390);
-    checkbox(w, L"Switch Windows input layout after conversion", 202, 18, 70, 390);
+    checkbox(w, L"Switch Windows input &layout after conversion", 202, 18, 70, 390);
-    checkbox(w, L"Record clipboard history", 203, 18, 106);
+    checkbox(w, L"Record clip&board history", 203, 18, 106);
-    checkbox(w, L"Start with Windows", 204, 18, 133);
+    checkbox(w, L"Start with &Windows", 204, 18, 133);
-    checkbox(w, L"Start with Windows as administrator", 206, 18, 160, 395);
+    checkbox(w, L"Start with Windows as ad&ministrator", 206, 18, 160, 395);
-    checkbox(w, L"Keep screen awake", 205, 18, 184, 210);
+    checkbox(w, L"&Keep screen awake", 205, 18, 184, 210);
-    checkbox(w, L"Write log", 208, 240, 184, 160);
+    checkbox(w, L"Write lo&g", 208, 240, 184, 160);
     label(w, L"Click a shortcut and press the desired keys", 420, 16, 350);
     const wchar_t *names[] = {L"Next layout", L"Change case", L"Transliterate", L"Undo",
                               L"Clipboard history", L"Screen capture"};
@@ -1666,18 +1711,18 @@ void showSettings(App &app, bool visible)
         label(w, names[i], 420, 48 + i * 30, 115);
         hotkeyEdit(app, w, 210 + i, 540, 44 + i * 30, 220);
     }
-    checkbox(w, L"Open editor after screen capture", 209, 420, 224, 340);
+    checkbox(w, L"Open editor after screen capt&ure", 209, 420, 224, 340);
-    checkbox(w, L"Automatically correct layout (experimental)", 207, 18, 210, 395);
+    checkbox(w, L"Automatic correction (e&xperimental)", 207, 18, 210, 395);
     label(w, L"Layout cycle — top to bottom", 18, 240, 400);
     control(w, L"LISTBOX", L"", WS_TABSTOP | WS_VSCROLL | LBS_NOTIFY | LBS_NOINTEGRALHEIGHT | WS_BORDER, 220,
             18, 262, 470, 172);
-    button(w, L"Move up", 232, 504, 262, 120);
+    button(w, L"Move u&p", 232, 504, 262, 120);
-    button(w, L"Move down", 233, 632, 262, 128);
+    button(w, L"Move &down", 233, 632, 262, 128);
-    checkbox(w, L"Include in cycle", 230, 504, 300, 240);
+    checkbox(w, L"&Include in cycle", 230, 504, 300, 240);
     label(w, L"Direct layout shortcut", 504, 332, 240);
     hotkeyEdit(app, w, 231, 504, 356, 256);
     label(w, L"Backspace / Delete clears a shortcut", 504, 382, 256);
-    button(w, L"Refresh layouts", 253, 504, 408, 150);
+    button(w, L"Re&fresh layouts", 253, 504, 408, 150);
     label(w, L"History limits", 18, 444);
     label(w, L"Items", 18, 478, 50);
     edit(w, 240, 70, 474, 90);
@@ -1685,17 +1730,18 @@ void showSettings(App &app, bool visible)
     edit(w, 241, 260, 474, 90);
     label(w, L"Per item MiB", 370, 478, 100);
     edit(w, 242, 475, 474, 80);
-    button(w, L"Clear history…", 254, 580, 474, 180);
+    button(w, L"Clear &history…", 254, 580, 474, 180);
     label(w, L"Exclude applications (process names, comma-separated)", 18, 516, 700);
     edit(w, 243, 18, 544, 742);
-    button(w, L"Auto-correction options…", 255, 18, 575, 240);
+    button(w, L"&Auto-correction options…", 255, 18, 575, 240);
-    button(w, L"View log…", 256, 278, 575, 220);
+    button(w, L"View l&og…", 256, 278, 575, 220);
-    button(w, L"OCR options…", 257, 518, 575, 242);
+    button(w, L"OCR op&tions…", 257, 518, 575, 242);
-    button(w, L"Import settings…", 250, 18, 606, 145);
+    button(w, L"Impo&rt settings…", 250, 18, 606, 145);
-    button(w, L"Export settings…", 251, 173, 606, 145);
+    button(w, L"&Export settings…", 251, 173, 606, 145);
-    button(w, L"Snippets…", 252, 328, 606, 110);
+    button(w, L"S&nippets…", 252, 328, 606, 110);
-    button(w, L"Save", IDOK, 548, 606, 100);
+    button(w, L"S&ync...", 258, 448, 606, 90);
-    button(w, L"Cancel", IDCANCEL, 660, 606, 100);
+    button(w, L"&Save", IDOK, 548, 606, 100);
+    button(w, L"&Cancel", IDCANCEL, 660, 606, 100);
     fillSettings(w, (SettingsView *)GetWindowLongPtrW(w, GWLP_USERDATA));
     if (visible)
     {
@@ -1715,17 +1761,17 @@ void showSnippets(App &app)
     label(w, L"Triggers", 16, 16);
     control(w, L"LISTBOX", L"", WS_TABSTOP | WS_VSCROLL | LBS_NOTIFY | LBS_NOINTEGRALHEIGHT | WS_BORDER, 301,
             16, 44, 200, 380);
-    button(w, L"Add", 310, 16, 438, 90);
+    button(w, L"&Add", 310, 16, 438, 90);
-    button(w, L"Delete", 311, 116, 438, 100);
+    button(w, L"&Delete", 311, 116, 438, 100);
-    label(w, L"Trigger (for example ;addr)", 236, 16, 470);
+    label(w, L"&Trigger (for example ;addr)", 236, 16, 470);
     edit(w, 302, 236, 44, 488);
-    label(w, L"Replacement text", 236, 82, 480);
+    label(w, L"&Replacement text", 236, 82, 480);
     edit(w, 303, 236, 110, 488, 270, ES_MULTILINE | ES_WANTRETURN | ES_AUTOVSCROLL | WS_VSCROLL);
     control(w, L"STATIC", L"{cursor}: caret; {enter}: press Enter after insertion.\nUse {{cursor}} / {{enter}} for literal markers.", 0, 0, 236, 392, 488, 36);
-    button(w, L"Insert cursor marker", 312, 236, 430, 190);
+    button(w, L"Insert cursor &marker", 312, 236, 430, 190);
-    button(w, L"Insert Enter marker", 313, 436, 430, 190);
+    button(w, L"Insert &Enter marker", 313, 436, 430, 190);
-    button(w, L"Save", IDOK, 510, 478, 100);
+    button(w, L"&Save", IDOK, 510, 478, 100);
-    button(w, L"Cancel", IDCANCEL, 624, 478, 100);
+    button(w, L"&Cancel", IDCANCEL, 624, 478, 100);
     fillSnippets(w, (SnippetView *)GetWindowLongPtrW(w, GWLP_USERDATA));
     showRequestedWindow(w);
     SetForegroundWindow(w);

src/ui_log.inl

@@ -309,18 +309,18 @@ void showLogs(App &app)
     SendMessageW(choice, CB_ADDSTRING, 0, (LPARAM)L"Current log — kswitcher.log");
     SendMessageW(choice, CB_ADDSTRING, 0, (LPARAM)L"Previous log — kswitcher.log.1");
     SendMessageW(choice, CB_SETCURSEL, 0, 0);
-    button(w, L"Refresh", LogRefresh, 310, 14, 100);
+    button(w, L"&Refresh", LogRefresh, 310, 14, 100);
-    button(w, L"Copy selected", LogCopy, 424, 14, 140);
+    button(w, L"&Copy selected", LogCopy, 424, 14, 140);
-    button(w, L"Clear log", LogClear, 578, 14, 100);
+    button(w, L"Clear &log", LogClear, 578, 14, 100);
     control(w, L"STATIC", L"", 0, LogStatus, 16, 49, 1068, 22);
-    label(w, L"Program", 16, 78, 170);
+    label(w, L"&Program", 16, 78, 170);
     control(w, L"COMBOBOX", L"", WS_TABSTOP | CBS_DROPDOWNLIST | WS_VSCROLL, LogProgram, 16, 101, 174, 300);
-    label(w, L"Command", 206, 78, 200);
+    label(w, L"Co&mmand", 206, 78, 200);
     control(w, L"COMBOBOX", L"", WS_TABSTOP | CBS_DROPDOWNLIST | WS_VSCROLL, LogCommand, 206, 101, 204, 300);
-    label(w, L"Result", 426, 78, 300);
+    label(w, L"Res&ult", 426, 78, 300);
     control(w, L"COMBOBOX", L"", WS_TABSTOP | CBS_DROPDOWNLIST | WS_VSCROLL, LogResult, 426, 101, 310, 300);
-    checkbox(w, L"Only problems", LogProblems, 752, 102, 166);
+    checkbox(w, L"&Only problems", LogProblems, 752, 102, 166);
-    button(w, L"Reset filters", LogReset, 938, 98, 146);
+    button(w, L"Reset &filters", LogReset, 938, 98, 146);
     INITCOMMONCONTROLSEX common{sizeof(common), ICC_LISTVIEW_CLASSES};
     InitCommonControlsEx(&common);
     auto list = control(w, WC_LISTVIEWW, L"", WS_TABSTOP | WS_BORDER | LVS_REPORT | LVS_SHOWSELALWAYS,
@@ -344,7 +344,7 @@ void showLogs(App &app)
         w, L"STATIC",
         L"Click a column to sort. Select an operation for details. Ctrl+C copies selected operations.", 0, 0,
         16, 712, 860, 22);
-    button(w, L"Close", IDCANCEL, 974, 708, 110);
+    button(w, L"Clos&e", IDCANCEL, 974, 708, 110);
     auto *layout = windowLayoutState(w);
     layout->stretch = list;
     layout->details = details;

src/ui_sync.inl

@@ -0,0 +1,149 @@
+#include "ui_sync_conflicts.inl"
+struct SyncView { HWND parent; App *app; };
+void updateSyncControls(HWND w, App &app)
+{
+    bool enabled = checked(w, 601);
+    bool savedEnabled = loadSyncConfig(app.data).enabled;
+    for (int id : {602, 603, 604, 605, 606, 607, 610, 611, 613})
+        EnableWindow(GetDlgItem(w, id), enabled);
+    EnableWindow(GetDlgItem(w, 612), enabled && savedEnabled);
+    EnableWindow(GetDlgItem(w, IDOK), enabled || savedEnabled);
+    value(w, IDOK, enabled ? L"&Save / Sign in / Sync" : L"&Save");
+    std::wstring status;
+    if (!enabled)
+        status = savedEnabled ? L"Click Save to disable synchronization." :
+              L"Synchronization is disabled. Enable it above to configure and sync.";
+    else if (!savedEnabled)
+        status = L"Configure the connection, then click Save / Sign in / Sync to enable synchronization.";
+    else
+        status = app.syncCommand();
+    if (value(w, 608) != status) value(w, 608, status);
+}
+SyncConfig syncFields(HWND w)
+{
+    SyncConfig c;
+    c.enabled = checked(w, 601);
+    c.keepLocalLayouts = checked(w, 613);
+    c.server = value(w, 602);
+    while (!c.server.empty() && c.server.back() == L'/') c.server.pop_back();
+    c.username = lower(value(w, 603)); c.mount = value(w, 605);
+    c.path = value(w, 606); c.authMount = value(w, 607);
+    return c;
+}
+LRESULT CALLBACK syncProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
+{
+    if (msg == WM_DPICHANGED) { resizeForDpi(w, wp, lp); return 0; }
+    auto *v = reinterpret_cast<SyncView *>(GetWindowLongPtrW(w, GWLP_USERDATA));
+    if (!v) return DefWindowProcW(w, msg, wp, lp);
+    try
+    {
+        if (msg == WM_TIMER)
+        {
+            updateSyncControls(w, *v->app);
+            return 0;
+        }
+        if (msg == WM_COMMAND)
+        {
+            int id = LOWORD(wp);
+            if (id == 601 && HIWORD(wp) == BN_CLICKED)
+            {
+                updateSyncControls(w, *v->app);
+                return 0;
+            }
+            if ((id == IDOK || id == 610 || id == 611 || id == 612) &&
+                !IsWindowEnabled(GetDlgItem(w, id))) return 0;
+            if (id == 612) { showSyncConflicts(w, *v->app); return 0; }
+            if (id == IDCANCEL) { DestroyWindow(w); return 0; }
+            if (id == 609)
+            {
+                auto c = loadSyncConfig(v->app->data);
+                c.enabled = false;
+                saveSyncConfig(v->app->data, c);
+                forgetSyncPassword(c);
+                check(w, 601, false);
+                value(w, 604, L"");
+                updateSyncControls(w, *v->app);
+                value(w, 608, L"Disabled. Saved password removed. An in-flight server request may still finish.");
+                KillTimer(w, 1);
+                return 0;
+            }
+            if (id == IDOK || id == 610 || id == 611)
+            {
+                if (!checked(w, 601))
+                {
+                    if (id != IDOK) return 0;
+                    auto c = loadSyncConfig(v->app->data);
+                    c.enabled = false;
+                    saveSyncConfig(v->app->data, c);
+                    value(w, 604, L"");
+                    updateSyncControls(w, *v->app);
+                    return 0;
+                }
+                if (id != IDOK && MessageBoxW(w, id == 610 ?
+                    L"Replace this PC's shared settings with the remote profile? A local backup will be saved. Unsaved edits in Settings are not included." :
+                    L"Replace the remote profile with this PC's saved settings? OpenBao retains older versions according to its retention policy. Unsaved edits are not included.",
+                    L"Resolve synchronization", MB_YESNO | MB_ICONWARNING) != IDYES) return 0;
+                auto c = syncFields(w);
+                if (c.enabled) validateSyncConfig(c);
+                auto password = value(w, 604);
+                try { if (!password.empty()) saveSyncPassword(c, password); }
+                catch (...) { SecureZeroMemory(password.data(), password.size() * sizeof(wchar_t)); throw; }
+                SecureZeroMemory(password.data(), password.size() * sizeof(wchar_t));
+                value(w, 604, L"");
+                saveSyncConfig(v->app->data, c);
+                value(w, 608, v->app->syncCommand(id == 610 ? 2 : id == 611 ? 3 : 1));
+                updateSyncControls(w, *v->app);
+                SetTimer(w, 1, 1000, nullptr);
+                return 0;
+            }
+        }
+    }
+    catch (const std::exception &e)
+    {
+        // Never display parser exceptions containing connection file contents.
+        value(w, 608, L"Unable to complete sync action. Check connection fields and saved configuration.");
+        if (dynamic_cast<const std::runtime_error *>(&e))
+            value(w, 608, wide(e.what()));
+        return 0;
+    }
+    if (msg == WM_CLOSE) { DestroyWindow(w); return 0; }
+    if (msg == WM_NCDESTROY)
+    {
+        KillTimer(w, 1);
+        EnableWindow(v->parent, TRUE); SetForegroundWindow(v->parent);
+        disposeFont(w); delete v; SetWindowLongPtrW(w, GWLP_USERDATA, 0);
+    }
+    return DefWindowProcW(w, msg, wp, lp);
+}
+void showSyncOptions(HWND parent, App &app)
+{
+    auto c = loadSyncConfig(app.data);
+    HWND w = makeWindow(app, L"KSwitcher.Sync", L"Settings synchronization - OpenBao", syncProc, 660, 672);
+    SetWindowLongPtrW(w, GWLP_HWNDPARENT, (LONG_PTR)parent);
+    SetWindowLongPtrW(w, GWLP_USERDATA, (LONG_PTR)new SyncView{parent, &app});
+    checkbox(w, L"&Enable synchronization with your OpenBao (KV v2)", 601, 18, 18, 620);
+    check(w, 601, c.enabled);
+    label(w, L"Se&rver (HTTPS)", 18, 60, 160); edit(w, 602, 190, 56, 450); value(w, 602, c.server);
+    label(w, L"User&name", 18, 100, 160); edit(w, 603, 190, 96, 450); value(w, 603, c.username);
+    label(w, L"&Password", 18, 140, 160); edit(w, 604, 190, 136, 450, 25, ES_AUTOHSCROLL | ES_PASSWORD);
+    label(w, L"Leave password blank to use the saved Windows credential.", 190, 166, 450);
+    label(w, L"KV v2 &mount", 18, 210, 160); edit(w, 605, 190, 206, 450); value(w, 605, c.mount);
+    label(w, L"Profile pa&th", 18, 250, 160); edit(w, 606, 190, 246, 450); value(w, 606, c.path);
+    label(w, L"&Login mount", 18, 290, 160); edit(w, 607, 190, 286, 450); value(w, 607, c.authMount);
+    label(w, L"Sync uses saved settings. Close and reopen Settings after downloading changes.", 18, 330, 622);
+    edit(w, 608, 18, 362, 622, 76, ES_MULTILINE | ES_READONLY | WS_VSCROLL | ES_AUTOVSCROLL);
+    value(w, 608, app.syncCommand());
+    checkbox(w, L"&Keep this PC's layouts and layout shortcuts (sync other settings)", 613, 18, 446, 622);
+    check(w, 613, c.keepLocalLayouts);
+    button(w, L"&Save / Sign in / Sync", IDOK, 18, 484, 200);
+    button(w, L"&Download remote", 610, 230, 484, 195);
+    button(w, L"&Upload local", 611, 437, 484, 203);
+    button(w, L"Resolve &individual conflicts...", 612, 18, 530, 300);
+    label(w, L"Background check: every 10 minutes", 330, 534, 310);
+    button(w, L"Disconnect / &forget password", 609, 18, 582, 290);
+    button(w, L"&Close", IDCANCEL, 540, 582, 100);
+    updateSyncControls(w, app);
+    EnableWindow(parent, FALSE);
+    SetTimer(w, 1, 1000, nullptr);
+    showRequestedWindow(w); SetForegroundWindow(w);
+}

src/ui_sync_conflicts.inl

@@ -0,0 +1,80 @@
+struct SyncConflictView
+{
+    HWND parent;
+    App *app;
+    std::vector<SyncConflict> conflicts;
+    std::map<size_t, bool> choices;
+};
+void showConflictValues(HWND w, SyncConflictView *v)
+{
+    int selected = (int)SendDlgItemMessageW(w, 620, LB_GETCURSEL, 0, 0);
+    if (selected < 0 || selected >= (int)v->conflicts.size()) return;
+    const auto &c = v->conflicts[selected];
+    value(w, 621, syncValueText(c.local)); value(w, 622, syncValueText(c.remote));
+}
+LRESULT CALLBACK syncConflictsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
+{
+    if (msg == WM_DPICHANGED) { resizeForDpi(w, wp, lp); return 0; }
+    auto *v = reinterpret_cast<SyncConflictView *>(GetWindowLongPtrW(w, GWLP_USERDATA));
+    if (!v) return DefWindowProcW(w, msg, wp, lp);
+    try
+    {
+        if (msg == WM_COMMAND)
+        {
+            int id = LOWORD(wp);
+            if (id == 620 && HIWORD(wp) == LBN_SELCHANGE) { showConflictValues(w, v); return 0; }
+            if (id == 623 || id == 624)
+            {
+                int selected = (int)SendDlgItemMessageW(w, 620, LB_GETCURSEL, 0, 0);
+                if (selected < 0 || selected >= (int)v->conflicts.size()) return 0;
+                v->choices[selected] = id == 623;
+                auto text = v->conflicts[selected].label + (id == 623 ? L"  [This PC]" : L"  [Server]");
+                SendDlgItemMessageW(w, 620, LB_DELETESTRING, selected, 0);
+                SendDlgItemMessageW(w, 620, LB_INSERTSTRING, selected, (LPARAM)text.c_str());
+                SendDlgItemMessageW(w, 620, LB_SETCURSEL, selected, 0);
+                return 0;
+            }
+            if (id == IDOK)
+            {
+                if (v->choices.empty()) throw std::runtime_error("Select a setting and choose This PC or Server first.");
+                std::vector<SyncChoice> choices;
+                for (const auto &[index, local] : v->choices) choices.push_back({v->conflicts.at(index), local});
+                auto status = v->app->syncCommand(4, choices);
+                value(v->parent, 608, status);
+                if (status != L"Connecting to OpenBao...") throw std::runtime_error(utf8(status));
+                DestroyWindow(w); return 0;
+            }
+            if (id == IDCANCEL) { DestroyWindow(w); return 0; }
+        }
+    }
+    catch (const std::exception &e) { error(w, e); return 0; }
+    if (msg == WM_CLOSE) { DestroyWindow(w); return 0; }
+    if (msg == WM_NCDESTROY)
+    {
+        EnableWindow(v->parent, TRUE); SetForegroundWindow(v->parent);
+        disposeFont(w); delete v; SetWindowLongPtrW(w, GWLP_USERDATA, 0);
+    }
+    return DefWindowProcW(w, msg, wp, lp);
+}
+void showSyncConflicts(HWND parent, App &app)
+{
+    auto conflicts = decodeSyncConflicts(app.syncConflictData());
+    if (conflicts.empty()) { value(parent, 608, L"No pending conflicts. Run Sync to check for changes."); return; }
+    HWND w = makeWindow(app, L"KSwitcher.SyncConflicts", L"Resolve individual settings", syncConflictsProc, 800, 560);
+    SetWindowLongPtrW(w, GWLP_HWNDPARENT, (LONG_PTR)parent);
+    auto *v = new SyncConflictView{parent, &app, std::move(conflicts), {}};
+    SetWindowLongPtrW(w, GWLP_USERDATA, (LONG_PTR)v);
+    label(w, L"Choose a value for each conflicting setting. Other changes are already synchronized.", 18, 16, 760);
+    control(w, L"LISTBOX", L"", WS_TABSTOP | WS_VSCROLL | LBS_NOTIFY | WS_BORDER, 620, 18, 48, 760, 130);
+    for (const auto &c : v->conflicts) SendDlgItemMessageW(w, 620, LB_ADDSTRING, 0, (LPARAM)c.label.c_str());
+    label(w, L"This PC", 18, 190, 360); label(w, L"Server", 410, 190, 368);
+    edit(w, 621, 18, 220, 368, 180, ES_MULTILINE | ES_READONLY | ES_AUTOVSCROLL | WS_VSCROLL);
+    edit(w, 622, 410, 220, 368, 180, ES_MULTILINE | ES_READONLY | ES_AUTOVSCROLL | WS_VSCROLL);
+    button(w, L"Use this &PC for selected setting", 623, 18, 412, 368);
+    button(w, L"Use &server for selected setting", 624, 410, 412, 368);
+    label(w, L"Unselected conflicts stay pending. Changed values will be checked again before saving.", 18, 454, 760);
+    button(w, L"&Apply choices", IDOK, 526, 488, 140);
+    button(w, L"&Cancel", IDCANCEL, 678, 488, 100);
+    SendDlgItemMessageW(w, 620, LB_SETCURSEL, 0, 0); showConflictValues(w, v);
+    EnableWindow(parent, FALSE); showRequestedWindow(w); SetForegroundWindow(w);
+}

src/update.h

@@ -2,7 +2,7 @@
 #include "platform.h"
 namespace ks
 {
-inline constexpr wchar_t AppVersion[] = L"0.6.20";
+inline constexpr wchar_t AppVersion[] = L"0.6.30";
 inline constexpr UINT UpdateMessage = WM_APP + 7;
 inline constexpr UINT UpdateCheckIntervalMs = 6 * 60 * 60 * 1000;
 inline constexpr UINT UpdateNotificationRetryMs = 5 * 60 * 1000;

tests/input.cpp

@@ -15,6 +15,37 @@ struct InputRegressionAccess {
     static inline bool delivery = true;
     static inline int notifications = 0;
     static bool notify(const std::wstring &) { ++notifications; return delivery; }
+    static void sampleConflicts(App &a) {
+        a.conflictConnection=loadSyncConfig(a.data);
+        a.pendingSyncConflicts={{"/autoCorrectMinLength",L"Minimum word length",{'4'},{'5'}}};
+    }
+    static bool staleSync(App &a, bool connectionChanged) {
+        auto before=encodeSettings(a.settings);
+        a.syncConnection=loadSyncConfig(a.data);
+        a.syncSnapshot=before;
+        if(connectionChanged) a.syncConnection.enabled=!a.syncConnection.enabled;
+        else a.syncSnapshot.clear();
+        auto remote=a.settings; remote.recent=!remote.recent;
+        a.syncResult={true,sharedSyncSettings(remote),2,L"test"};
+        a.syncWorker=std::thread([]{});
+        a.syncRunning=true; a.syncDone=true;
+        a.pollSync();
+        return encodeSettings(a.settings)==before && !a.syncRunning &&
+            !std::filesystem::exists(a.data/L"sync-base.bin");
+    }
+    static bool syncBackoff(App &a) {
+        a.syncRetryAfter=GetTickCount64()+15*60000;
+        auto previous=a.settings;
+        auto next=previous;
+        next.toggle=next.casing=next.translit=next.undo=next.clipboard=next.screenshot=L"";
+        next.direct.clear(); next.directIds.clear();
+        // This harness deliberately has no global keyboard hook.
+        a.applySettings(next);
+        bool preserved=a.nextSync==a.syncRetryAfter;
+        a.settings=previous;
+        a.syncRetryAfter=0;
+        return preserved;
+    }
     static void notificationSetup(App &a) { a.updateNotifier = notify; }
     static void setup(App &a) { a.hookBindings = {{Toggle,{MOD_CONTROL,VK_F12}}, {Case,{MOD_CONTROL|MOD_SHIFT,'U'}}}; }
     static bool updateTimer(App &a) {
@@ -568,6 +599,9 @@ int main(int argc, char **argv) {
             require(!app.handleKeyboard(f12,true,MOD_CONTROL|MOD_SHIFT),"exact modifiers only");
             app.resetInput();
             app.handleKeyboard(event('A',0x1e),true,0);
+            if (app.run.keys!=L"a" && app.run.keys!=L"A")
+                std::cerr << "Input fixture foreground=" << (uintptr_t)GetForegroundWindow()
+                          << " recorded=" << ks::utf8(app.run.keys) << '\n';
             require(app.run.keys==L"a"||app.run.keys==L"A","external scan recorded with current CapsLock");
             auto keys=app.run.keys; auto version=app.inputVersion.load();
             for(WORD key:{WORD('V'),WORD(VK_SHIFT),WORD(VK_LEFT),WORD(VK_F15),WORD(0xE8)})
@@ -595,6 +629,94 @@ int main(int argc, char **argv) {
             fitted=ks::fitWindowRect({2000,2000,2600,2400},{-1920,0,0,1080});
             require(fitted.left==-600&&fitted.top==680&&fitted.right==0,"negative-coordinate monitor supported");
             ks::showSettings(app,false);
+            require(GetDlgItem(app.settingsWindow,258)!=nullptr,"sync available without local opt-in");
+            // Mnemonics only target visible controls; show without taking foreground focus.
+            ShowWindow(app.settingsWindow,SW_SHOWNOACTIVATE);
+            auto previousActive=SetActiveWindow(app.settingsWindow);
+            auto awakeBefore=SendDlgItemMessageW(app.settingsWindow,205,BM_GETCHECK,0,0);
+            MSG accessKey{}; accessKey.hwnd=GetDlgItem(app.settingsWindow,201);
+            accessKey.message=WM_SYSCHAR; accessKey.wParam=L'k'; accessKey.lParam=1LL<<29;
+            require(IsDialogMessageW(app.settingsWindow,&accessKey),"Alt+K is handled as a dialog access key");
+            MSG dispatched{};
+            while(PeekMessageW(&dispatched,nullptr,0,0,PM_REMOVE)) { TranslateMessage(&dispatched); DispatchMessageW(&dispatched); }
+            require(SendDlgItemMessageW(app.settingsWindow,205,BM_GETCHECK,0,0)!=awakeBefore,
+                    "Alt+K toggles Keep screen awake");
+            IsDialogMessageW(app.settingsWindow,&accessKey);
+            while(PeekMessageW(&dispatched,nullptr,0,0,PM_REMOVE)) { TranslateMessage(&dispatched); DispatchMessageW(&dispatched); }
+            require(SendDlgItemMessageW(app.settingsWindow,205,BM_GETCHECK,0,0)==awakeBefore,
+                    "repeated access key restores checkbox state");
+            ShowWindow(app.settingsWindow,SW_HIDE);
+            SetActiveWindow(previousActive);
+
+            DestroyWindow(app.settingsWindow);
+            ks::saveSyncConfig(app.data,ks::SyncConfig{});
+            ks::showSettings(app,false);
+            require(GetDlgItem(app.settingsWindow,258)!=nullptr,"sync button available after local opt-in");
+            SendMessageW(app.settingsWindow,WM_COMMAND,258,0);
+            auto syncWindow=FindWindowW(L"KSwitcher.Sync",nullptr);
+            require(syncWindow!=nullptr,"private sync dialog opens");
+            ShowWindow(syncWindow,SW_HIDE);
+            require((GetWindowLongPtrW(GetDlgItem(syncWindow,604),GWL_STYLE)&ES_PASSWORD)!=0,
+                    "sync password is masked");
+            require(!IsWindowEnabled(app.settingsWindow),"sync dialog owns settings interaction");
+            for(int id:{602,603,604,605,606,607,610,611,612,613,IDOK})
+                require(!IsWindowEnabled(GetDlgItem(syncWindow,id)),"disabled synchronization disables dependent controls");
+            require(IsWindowEnabled(GetDlgItem(syncWindow,601)) && IsWindowEnabled(GetDlgItem(syncWindow,609)) &&
+                    IsWindowEnabled(GetDlgItem(syncWindow,IDCANCEL)),"enable, forget password and close remain available");
+            SendMessageW(syncWindow,WM_COMMAND,612,0);
+            require(!FindWindowW(L"KSwitcher.SyncConflicts",nullptr),"disabled conflict action is ignored");
+            SendDlgItemMessageW(syncWindow,601,BM_SETCHECK,BST_CHECKED,0);
+            SendMessageW(syncWindow,WM_COMMAND,MAKEWPARAM(601,BN_CLICKED),0);
+            for(int id:{602,603,604,605,606,607,610,611,613,IDOK})
+                require(IsWindowEnabled(GetDlgItem(syncWindow,id)),"enabling synchronization immediately enables connection controls");
+            require(!ks::loadSyncConfig(app.data).enabled,"checking enable alone does not connect or persist");
+            auto enabledSync=ks::loadSyncConfig(app.data);
+            enabledSync.enabled=true;
+            enabledSync.server=L"https://sync.example.test";
+            enabledSync.username=L"test";
+            ks::saveSyncConfig(app.data,enabledSync);
+            SendMessageW(syncWindow,WM_COMMAND,MAKEWPARAM(601,BN_CLICKED),0);
+            ks::InputRegressionAccess::sampleConflicts(app);
+            SendMessageW(syncWindow,WM_COMMAND,612,0);
+            auto conflictsWindow=FindWindowW(L"KSwitcher.SyncConflicts",nullptr);
+            require(conflictsWindow!=nullptr,"per-setting conflict dialog opens");
+            ShowWindow(conflictsWindow,SW_HIDE);
+            require(SendDlgItemMessageW(conflictsWindow,620,LB_GETCOUNT,0,0)==1,"conflict shown as separate setting");
+            wchar_t conflictValue[20]{}; GetDlgItemTextW(conflictsWindow,621,conflictValue,20);
+            require(std::wstring(conflictValue)==L"4","local conflict value shown");
+            GetDlgItemTextW(conflictsWindow,622,conflictValue,20);
+            require(std::wstring(conflictValue)==L"5","remote conflict value shown");
+            for(int id:{620,621,622,623,624,IDOK,IDCANCEL}) {
+                RECT control{},client{};
+                GetWindowRect(GetDlgItem(conflictsWindow,id),&control);
+                MapWindowPoints(nullptr,conflictsWindow,reinterpret_cast<POINT*>(&control),2);
+                GetClientRect(conflictsWindow,&client);
+                require(control.left>=0&&control.top>=0&&control.right<=client.right&&control.bottom<=client.bottom,
+                        "conflict controls fit dialog");
+            }
+            SendMessageW(conflictsWindow,WM_COMMAND,623,0);
+            require(!IsWindowEnabled(syncWindow),"conflict dialog owns sync interaction");
+            SendMessageW(conflictsWindow,WM_COMMAND,IDCANCEL,0);
+            require(IsWindowEnabled(syncWindow),"closing conflict dialog restores sync window");
+            for(int id:{601,602,603,604,605,606,607,608,609,610,611,612,613,IDOK,IDCANCEL}) {
+                RECT control{},client{};
+                GetWindowRect(GetDlgItem(syncWindow,id),&control);
+                MapWindowPoints(nullptr,syncWindow,reinterpret_cast<POINT*>(&control),2);
+                GetClientRect(syncWindow,&client);
+                require(control.left>=0&&control.top>=0&&control.right<=client.right&&control.bottom<=client.bottom,
+                        "sync controls fit dialog");
+            }
+            SendDlgItemMessageW(syncWindow,601,BM_SETCHECK,BST_UNCHECKED,0);
+            SendMessageW(syncWindow,WM_COMMAND,MAKEWPARAM(601,BN_CLICKED),0);
+            require(IsWindowEnabled(GetDlgItem(syncWindow,IDOK)),"Save remains available to persist disabling sync");
+            SendMessageW(syncWindow,WM_COMMAND,IDOK,0);
+            require(!ks::loadSyncConfig(app.data).enabled,"saving disabled sync does not enable network access");
+            require(!IsWindowEnabled(GetDlgItem(syncWindow,IDOK)),"Save disables after disabled state is persisted");
+            SendMessageW(syncWindow,WM_COMMAND,IDCANCEL,0);
+            require(IsWindowEnabled(app.settingsWindow),"closing sync restores parent");
+            require(ks::InputRegressionAccess::staleSync(app,false),"in-flight sync cannot overwrite newer local edits");
+            require(ks::InputRegressionAccess::staleSync(app,true),"disconnect discards in-flight downloaded profile");
+            require(ks::InputRegressionAccess::syncBackoff(app),"saving settings preserves authentication error backoff");
             SendMessageW(app.settingsWindow,WM_COMMAND,255,0);
             auto autoOptions=FindWindowW(L"KSwitcher.AutoOptions",nullptr);
             require(autoOptions!=nullptr,"auto-correction options open");
@@ -606,21 +728,31 @@ int main(int argc, char **argv) {
                 GetWindowRect(autoOptions,&original);
                 // Use a client size above the scrolling baseline at every DPI.
                 UINT dpi=GetDpiForWindow(autoOptions);
-                SetWindowPos(autoOptions,nullptr,0,0,MulDiv(800,dpi,96),MulDiv(900,dpi,96),
+                SetWindowPos(autoOptions,nullptr,0,0,MulDiv(800,dpi,96),MulDiv(1100,dpi,96),
                              SWP_NOMOVE|SWP_NOZORDER|SWP_NOACTIVATE);
                 RECT baseline{}; GetWindowRect(autoOptions,&baseline);
+                RECT clientBefore{}; GetClientRect(autoOptions,&clientBefore);
                 for(int i=0;i<3;++i) GetWindowRect(GetDlgItem(autoOptions,411+i),&before[i]);
                 GetWindowRect(GetDlgItem(autoOptions,IDOK),&buttonBefore);
                 SetWindowPos(autoOptions,nullptr,0,0,baseline.right-baseline.left+240,
                              baseline.bottom-baseline.top+120,SWP_NOMOVE|SWP_NOZORDER|SWP_NOACTIVATE);
+                RECT clientAfter{}; GetClientRect(autoOptions,&clientAfter);
+                // Windows can constrain oversized windows to the current desktop.
+                // Check layout against the actual available client space.
+                int extraBeforeX=std::max(0,int(clientBefore.right)-MulDiv(560,dpi,96));
+                int extraAfterX=std::max(0,int(clientAfter.right)-MulDiv(560,dpi,96));
+                int extraY=std::max(0,int(clientAfter.bottom)-MulDiv(880,dpi,96))-
+                           std::max(0,int(clientBefore.bottom)-MulDiv(880,dpi,96));
                 for(int i=0;i<3;++i) {
                     GetWindowRect(GetDlgItem(autoOptions,411+i),&after[i]);
-                    require(after[i].right-after[i].left==before[i].right-before[i].left+80 &&
+                    int extraX=(extraAfterX*(i+1)/3-extraAfterX*i/3)-
-                            after[i].bottom-after[i].top==before[i].bottom-before[i].top+120,
+                               (extraBeforeX*(i+1)/3-extraBeforeX*i/3);
+                    require(after[i].right-after[i].left==before[i].right-before[i].left+extraX &&
+                            after[i].bottom-after[i].top==before[i].bottom-before[i].top+extraY,
                             "dictionary columns share extra width and receive extra height");
                 }
                 GetWindowRect(GetDlgItem(autoOptions,IDOK),&buttonAfter);
-                require(buttonAfter.left-buttonBefore.left==240 && buttonAfter.top-buttonBefore.top==120,
+                require(buttonAfter.left-buttonBefore.left==extraAfterX-extraBeforeX && buttonAfter.top-buttonBefore.top==extraY,
                         "auto-correction buttons follow bottom-right corner");
                 require(after[0].right<after[1].left && after[1].right<after[2].left &&
                             after[2].bottom<buttonAfter.top,
@@ -637,6 +769,9 @@ int main(int argc, char **argv) {
                         "personal dictionary field fits options window");
             }
             SetDlgItemTextW(autoOptions,412,L"Релізик\r\nрелізик, словечко");
+            SetDlgItemTextW(autoOptions,416,L" Првиіт = Привіт\r\nhelo=hello");
+            SendDlgItemMessageW(autoOptions,414,BM_SETCHECK,BST_CHECKED,0);
+            SendDlgItemMessageW(autoOptions,415,BM_SETCHECK,BST_CHECKED,0);
             SendMessageW(autoOptions,WM_COMMAND,IDOK,0);
             require(!IsWindow(autoOptions),"personal words accepted without file editing");
             SendMessageW(app.settingsWindow,WM_COMMAND,255,0);
@@ -646,6 +781,12 @@ int main(int argc, char **argv) {
             GetDlgItemTextW(autoOptions,412,personalWords,128);
             require(std::wstring(personalWords)==L"релізик, словечко",
                     "personal dictionary normalizes case, newlines and duplicate words");
+            wchar_t pairs[128]{};
+            GetDlgItemTextW(autoOptions,416,pairs,128);
+            require(std::wstring(pairs)==L"helo=hello\r\nпрвиіт=привіт\r\n" &&
+                    SendDlgItemMessageW(autoOptions,414,BM_GETCHECK,0,0)==BST_CHECKED &&
+                    SendDlgItemMessageW(autoOptions,415,BM_GETCHECK,0,0)==BST_CHECKED,
+                    "typo options and normalized replacement pairs survive reopening");
             SendMessageW(autoOptions,WM_COMMAND,IDCANCEL,0);
             if (!app.history) app.history=std::make_unique<ks::History>(temp/L"history-layout");
             ks::showHistory(app,false);

tests/integration.cpp

@@ -9,6 +9,7 @@ namespace ks
 {
 struct InputRegressionAccess
 {
+    static bool hasLast(App &app) { return app.last.has_value(); }
     static bool deferring(App &app)
     {
         std::lock_guard lock(app.stateMutex);
@@ -23,13 +24,21 @@ HWND host{}, field{};
 ks::Clip saved;
 bool captured = false, failed = false;
 bool conversionOnly = false;
+bool typosOnly = false;
 int pasteBehavior = 0;
 int enterPresses = 0;
 int copyFailuresRemaining = 0, copyRequests = 0;
+int droppedSelectionKeys = 0;
 bool temporaryClipboardExcluded = true;
 bool clipboardAccessTimedOut = false;
 LRESULT CALLBACK observeEnter(HWND w, UINT message, WPARAM wp, LPARAM lp, UINT_PTR, DWORD_PTR)
 {
+    if (message == WM_KEYDOWN && wp == VK_LEFT && droppedSelectionKeys > 0 &&
+        (GetKeyState(VK_SHIFT) & 0x8000))
+    {
+        --droppedSelectionKeys;
+        return 0;
+    }
     // This bare EDIT control is our test fixture, not a full editor with
     // clipboard retries. Keep clipboard access on its owning UI thread while
     // it handles Ctrl+C/Ctrl+V, so unrelated Windows clipboard listeners cannot
@@ -72,6 +81,7 @@ LRESULT CALLBACK observeEnter(HWND w, UINT message, WPARAM wp, LPARAM lp, UINT_P
     }
     if (message == WM_PASTE && pasteBehavior)
     {
+        if (pasteBehavior == 3) { pasteBehavior = 0; return 0; }
         if (pasteBehavior == 2) SendMessageW(w, EM_REPLACESEL, TRUE, (LPARAM)L"other!");
         return 0;
     }
@@ -205,10 +215,12 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 break;
             case 3:
                 require(text() == L"Hello World", "case conversion");
+                droppedSelectionKeys = 5;
                 app->transform(ks::Case);
                 break;
             case 4:
                 require(text() == L"HELLO WORLD", "consecutive command reselects verified previous result");
+                require(droppedSelectionKeys == 0, "partial suffix selection recovered after dropped arrow keys");
                 prepare(L"OLDghbdtn", false);
                 record(L"ghbdtn");
                 app->transform(ks::Direct + ru);
@@ -361,6 +373,7 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 require(text() == L"ghbdtn" && rows.back().outcome == L"Original text remained",
                         "blocked paste records original text remaining in the actual editor");
                 require(ks::readClipboard(app->window).text() == sentinel, "readback preserves clipboard after blocked paste");
+                require(!ks::InputRegressionAccess::hasLast(*app), "failed paste does not retain a fictional previous result");
                 pasteBehavior = 2;
                 prepare(L"ghbdtn", true);
                 app->transform(ks::Direct + ru);
@@ -371,6 +384,7 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 auto rows = ks::parseOperationLog(ks::wide(diagnosticLog()));
                 require(text() == L"other!" && rows.back().outcome == L"Readback differs",
                         "unexpected editor content records readback mismatch");
+                require(!ks::InputRegressionAccess::hasLast(*app), "changed readback cannot seed repeat conversion");
                 pasteBehavior = 0;
                 prepare(L"привет", true);
                 app->transform(ks::Direct + ru);
@@ -392,8 +406,67 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 require(text() == L"привет" && diagnosticLog().size() == diagnosticStart,
                         "disabled diagnostics preserves conversion and writes no records");
                 ks::setLoggingEnabled(true);
+                prepare(L"PuntoSwitcher ", true);
+                app->transform(ks::Direct + ru);
+                break;
+            case 44:
+                app->transform(ks::Direct + en);
+                break;
+            case 45:
+                require(text() == L"PuntoSwitcher ", "previous conversion restores CamelCase and trailing space");
+                droppedSelectionKeys = 5;
+                app->transform(ks::Direct + ru);
+                break;
+            case 46:
+                require(text() == ks::convertTo(L"PuntoSwitcher ", app->layouts, ru, en),
+                        "repeat conversion recovers Switcher suffix and preserves full result");
+                require(droppedSelectionKeys == 0, "CamelCase suffix regression dropped five selection keys");
+                require(ks::readClipboard(app->window).text() == sentinel,
+                        "suffix recovery restores original clipboard");
+                // Derive the actual text from the physical keys, preserving an older prefix.
+                prepare((L"OLD" + ks::convertTo(L"snipping ", app->layouts, ru, en)).c_str(), false);
+                record(L"snipping ");
+                droppedSelectionKeys = 4;
+                app->transform(ks::Direct + en);
+                break;
+            case 47:
+                require(text() == L"OLDsnipping ", "recent Cyrillic suffix recovery preserves older prefix");
+                require(droppedSelectionKeys == 0, "recent suffix regression dropped four selection keys");
+                app->settings.writeLog = true;
+                prepare(L"prefix wrong ", false);
+                record(L"other ");
+                app->transform(ks::Direct + ru);
+                break;
+            case 48:
+            {
+                auto rows = ks::parseOperationLog(ks::wide(diagnosticLog()));
+                require(text() == L"prefix wrong " && !rows.empty() &&
+                        rows.back().outcome == L"recent-verification-mismatch",
+                        "diagnostic mismatch does not replace unverified text");
+                auto details = rows.back().details;
+                require(details.find(L"selection-mismatch") != details.npos &&
+                        details.find(L"Expected selection:\r\nother ") != details.npos &&
+                        details.find(L"Read back:\r\nwrong ") != details.npos,
+                        "failed verification includes expected and copied text in exported details");
+                require(details.find(L"Copy begin number=") != details.npos &&
+                        details.find(L"Copy result number=") != details.npos &&
+                        details.find(L"Selection initial match=0") != details.npos &&
+                        details.find(L"SelectPrevious") != details.npos,
+                        "incident includes clipboard and selection stages");
+                pasteBehavior = 3;
+                prepare(L"=nhtdjuf", true);
+                app->transform(ks::Direct + ru);
+                stage = 49;
+                break;
+            }
+            case 49:
+            {
+                require(text() == L"=тревога" && pasteBehavior == 0,
+                        "native Edit retries one ignored paste only while original remains selected");
+                require(ks::readClipboard(app->window).text() == sentinel, "native paste retry restores clipboard");
                 finish();
                 break;
+            }
             case 30:
             case 32:
             case 34:
@@ -562,6 +635,61 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             }
             case 22:
                 require(text() == L"робить ", "automatic correction selects and converts the whole word across an internal comma");
+                app->settings.autoReplace = true;
+                app->settings.autoReplacements = {{L"helo", L"hello"}};
+                ActivateKeyboardLayout(app->layouts[en].handle, 0);
+                prepare(L"(Helo)! ", false);
+                record(L"(Helo)! ");
+                app->transform(ks::AutoCorrect);
+                break;
+            case 23:
+                require(text() == L"(Hello)! ", "explicit typo pair replaces verified text with punctuation and capital");
+                app->transform(ks::Undo);
+                break;
+            case 24:
+                require(text() == L"(Helo)! ", "Undo restores explicit typo replacement");
+                app->settings.autoReplace = false;
+                app->settings.autoTypos = true;
+                app->settings.autoWords[L"en"].push_back(L"kswitcher");
+                // Use a personal target to avoid bundled dictionary ambiguity.
+                prepare(L"kswithcer ", false);
+                record(L"kswithcer ");
+                app->transform(ks::AutoCorrect);
+                break;
+            case 25:
+                require(text() == L"kswitcher ", "dictionary typo correction replaces text in the current layout");
+                require(ks::readClipboard(app->window).text() == sentinel, "typo correction restores clipboard");
+                app->transform(ks::Undo);
+                break;
+            case 26:
+                require(text() == L"kswithcer ", "Undo restores dictionary typo correction");
+                record(L"kswithcer ");
+                app->transform(ks::AutoCorrect);
+                break;
+            case 27:
+                require(text() == L"kswithcer ", "Undo suppresses the rejected spelling correction");
+                app->settings.autoReplace = true;
+                app->settings.autoReplacements = {{L"tehh", L"the"}};
+                app->autoPredictor.configure(L"dictionaries", app->settings.autoLanguages);
+                prepare(L"", false);
+                {
+                    std::vector<INPUT> inputs;
+                    for (WORD key : std::wstring(L"TEHH X"))
+                        for (DWORD flags : {DWORD(0), DWORD(KEYEVENTF_KEYUP)})
+                        {
+                            auto input = ks::keyboardInput(key == L' ' ? VK_SPACE : key, flags);
+                            input.ki.dwExtraInfo = 123;
+                            inputs.push_back(input);
+                        }
+                    require(SendInput((UINT)inputs.size(), inputs.data(), sizeof(INPUT)) == inputs.size(),
+                            "custom typo and following word submitted without a pause");
+                }
+                break;
+            case 28:
+                require(text() == L"the x", "custom replacement through keyboard hook preserves subsequent typing");
+                app->settings.autoReplace = false;
+                app->settings.autoTypos = false;
+                if (typosOnly) { finish(); break; }
                 stage = 30;
                 break;
             }
@@ -586,6 +714,7 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
 int main(int argc, char **argv)
 {
     conversionOnly = argc > 1 && std::string(argv[1]) == "--conversion-only";
+    typosOnly = argc > 1 && std::string(argv[1]) == "--typos-only";
     CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED);
     auto root = std::filesystem::temp_directory_path() /
                 (L"KSwitcher-integration-" + std::to_wstring(GetCurrentProcessId()));
@@ -741,7 +870,7 @@ int main(int argc, char **argv)
                               20, 20, 590, 230, host, nullptr, cls.hInstance, nullptr);
             deadline = GetTickCount64() + 30000;
             SetWindowSubclass(field, observeEnter, 1, 0);
-            if (argc > 1 && std::string(argv[1]) == "--typing-only")
+            if (typosOnly || (argc > 1 && std::string(argv[1]) == "--typing-only"))
                 stage = 20;
             if (argc > 1 && std::string(argv[1]) == "--snippets-only")
                 stage = 30;

tests/screenshot_ui.cpp

@@ -2,10 +2,69 @@
 // Including the implementation lets this integration test drive private editor state directly.
 #include "../src/screenshot.cpp"
 #include <iostream>
-int main()
+#include "stroke_improvement.h"
+int main(int argc, char **argv)
 {
     CoInitializeEx(nullptr,COINIT_APARTMENTTHREADED);
     try {
+        testStrokeImprovement();
+        if(argc>1 && std::string(argv[1])=="--save-only") {
+            auto require=[](bool ok,const char *message){if(!ok) throw std::runtime_error(message);};
+            auto root=std::filesystem::temp_directory_path()/(L"KSwitcher-save-"+std::to_wstring(GetCurrentProcessId()));
+            std::filesystem::create_directories(root);
+            struct Cleanup {std::filesystem::path root; ~Cleanup(){std::error_code ec; std::filesystem::remove_all(root,ec);}} cleanup{root};
+            ks::ScreenshotHost app{GetModuleHandleW(nullptr)};
+            ks::Capture c(app);
+            c.image=std::make_unique<ks::Surface>(320,240);
+            PatBlt(c.image->dc,0,0,320,240,WHITENESS);
+            c.marks={ks::Mark{{40,40},{180,140},0}};
+            auto expected=ks::decodeImage(ks::screenshotClip(c.image->dc,320,240,c.marks));
+            for(size_t i=3;i<expected.bgra.size();i+=4) expected.bgra[i]=255;
+            auto path=root/L"Знімок.png";
+            const auto clipboard=GetClipboardSequenceNumber();
+            ks::saveToFile(nullptr,c,path);
+            ks::Clip encoded{{{0,L"PNG",ks::readFile(path,16*1024*1024)}}};
+            auto actual=ks::decodeImage(encoded);
+            require(actual.width==320 && actual.height==240 && actual.bgra==expected.bgra,
+                    "PNG export preserves full resolution, annotations and opaque pixels");
+            require(c.savedPath==path && c.copied,"successful save records destination and exported state");
+            require(GetClipboardSequenceNumber()==clipboard,"saving does not change clipboard");
+            c.remember(c.marks); c.marks.clear();
+            require(!c.copied,"editing after save marks changes unexported");
+            ks::save(nullptr,c);
+            actual=ks::decodeImage(ks::Clip{{{0,L"PNG",ks::readFile(path,16*1024*1024)}}});
+            require(actual.bgra!=expected.bgra && c.copied,"Save overwrites remembered path with current edits without a dialog");
+            c.copied=false;
+            ks::save(nullptr,c,true,[](LPOPENFILENAMEW dialog)->BOOL {
+                if(!(dialog->Flags&OFN_OVERWRITEPROMPT) || std::wstring(dialog->lpstrDefExt)!=L"png" ||
+                   !std::wstring(dialog->lpstrFile).ends_with(L"Знімок.png"))
+                    throw std::runtime_error("Save As dialog must preserve filename, PNG extension and overwrite confirmation");
+                return FALSE;
+            });
+            require(!c.copied && c.savedPath==path,"cancelled Save As preserves dirty state and remembered path");
+            auto another=root/L"Another.png";
+            ks::save(nullptr,c,true,[](LPOPENFILENAMEW dialog)->BOOL {
+                auto destination=std::filesystem::path(dialog->lpstrFile).parent_path()/L"Another.png";
+                wcscpy_s(dialog->lpstrFile,dialog->nMaxFile,destination.c_str());
+                return TRUE;
+            });
+            require(c.savedPath==another && std::filesystem::exists(path),"new destination preserves previous file");
+            c.copied=false;
+            bool failed=false;
+            try {ks::saveToFile(nullptr,c,root/L"missing"/L"fail.png");} catch(const std::exception &){failed=true;}
+            require(failed && !c.copied && c.savedPath==another,"failed save preserves dirty state and previous destination");
+            require(std::distance(std::filesystem::directory_iterator(root),std::filesystem::directory_iterator{})==2,
+                    "saving leaves no temporary files");
+            bool invalid=false;
+            try {ks::save(nullptr,c,true,[](LPOPENFILENAMEW dialog)->BOOL {
+                auto destination=std::filesystem::path(dialog->lpstrFile).parent_path()/L"Wrong.jpg";
+                wcscpy_s(dialog->lpstrFile,dialog->nMaxFile,destination.c_str()); return TRUE;
+            });} catch(const std::exception &){invalid=true;}
+            require(invalid && !std::filesystem::exists(root/L"Wrong.jpg"),"PNG export rejects a misleading file extension");
+            CoUninitialize();
+            std::cout<<"Passed screenshot PNG save regressions without opening windows\n";
+            return 0;
+        }
         INITCOMMONCONTROLSEX controls{sizeof(controls),ICC_STANDARD_CLASSES}; InitCommonControlsEx(&controls);
         ks::ScreenshotHost app{GetModuleHandleW(nullptr)};
         app.window=CreateWindowW(L"STATIC",L"",0,0,0,0,0,HWND_MESSAGE,nullptr,app.instance,nullptr);
@@ -24,6 +83,169 @@ int main()
         require(c.pencilCursor!=nullptr,"pencil drawing cursor loads");
         require(c.freehand && !c.pointer && ks::toolCursor(c)==c.pencilCursor,
                 "new screenshot editor starts with the pencil tool");
+        {
+            require(GetDlgItem(window,36)!=nullptr,"triangle has a dedicated toolbar button");
+            SendMessageW(window,WM_KEYDOWN,'G',0);
+            require(c.shape==ks::ScreenshotShape::Triangle && c.arrow && !c.freehand,"G selects triangle drawing tool");
+            auto mouse=[&](UINT message,POINT p) {
+                int x=c.view.left+MulDiv(p.x,c.view.right-c.view.left,c.image->width);
+                int y=c.view.top+MulDiv(p.y,c.view.bottom-c.view.top,c.image->height);
+                SendMessageW(window,message,message==WM_LBUTTONUP?0:MK_LBUTTON,MAKELPARAM(x,y));
+            };
+            mouse(WM_LBUTTONDOWN,{80,80}); mouse(WM_LBUTTONUP,{220,180});
+            require(c.marks.size()==1 && c.marks[0].shape==ks::ScreenshotShape::Triangle && c.marks[0].points.size()==4,
+                    "triangle tool creates a closed three-vertex shape");
+            auto triangle=c.marks[0];
+            for(double angle:{0.0,37.0,90.0,-125.0}) for(int i=0;i<3;++i) {
+                auto original=triangle; original.rotation=angle;
+                auto vertices=ks::shapeOutline(original);
+                auto part=ks::MarkPart(int(ks::MarkPart::Vertex0)+i);
+                require(ks::hitScreenshotMark(original,vertices[i],4)==part,"each rotated triangle vertex has its own handle");
+                POINT target{vertices[i].x+13,vertices[i].y-9};
+                auto changed=ks::dragScreenshotMark(original,part,vertices[i],target,320,240);
+                auto moved=ks::shapeOutline(changed);
+                for(int j=0;j<3;++j) {
+                    auto expected=j==i?target:vertices[j];
+                    require(std::abs(moved[j].x-expected.x)<=2 && std::abs(moved[j].y-expected.y)<=2,
+                            "dragging one vertex preserves both other world vertices after rotation");
+                }
+                require(changed.points.front().x==changed.points.back().x && changed.points.front().y==changed.points.back().y,
+                        "triangle remains closed after editing any vertex");
+            }
+            auto vertices=ks::shapeOutline(triangle);
+            mouse(WM_LBUTTONDOWN,vertices[0]);
+            require(c.part==ks::MarkPart::Vertex0,"mouse selects apex vertex");
+            mouse(WM_LBUTTONUP,{vertices[0].x+20,vertices[0].y+10});
+            require(c.marks[0].points[0].x==triangle.points[0].x+20 && c.marks[0].points[1].x==triangle.points[1].x,
+                    "mouse vertex drag changes only requested corner");
+            SendMessageW(window,WM_COMMAND,12,0);
+            require(c.marks[0].points[0].x==triangle.points[0].x,"undo restores triangle vertex");
+            SendMessageW(window,WM_COMMAND,18,0);
+            require(c.marks[0].points[0].x==triangle.points[0].x+20,"redo reapplies triangle vertex edit");
+            c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{};
+            require(GetDlgItem(window,37)!=nullptr,"trapezoid has a dedicated toolbar button");
+            SendMessageW(window,WM_KEYDOWN,'B',0);
+            require(c.shape==ks::ScreenshotShape::Trapezoid && c.arrow && !c.freehand,"B selects trapezoid tool");
+            mouse(WM_LBUTTONDOWN,{60,70}); mouse(WM_LBUTTONUP,{240,180});
+            require(c.marks.size()==1 && c.marks[0].shape==ks::ScreenshotShape::Trapezoid && c.marks[0].points.size()==5 && !c.marks[0].isHighlight(),
+                    "trapezoid tool creates a closed shape with unequal parallel bases");
+            auto trapezoid=c.marks[0];
+            require(trapezoid.points[0].y==trapezoid.points[1].y && trapezoid.points[2].y==trapezoid.points[3].y &&
+                    trapezoid.points[1].x-trapezoid.points[0].x<trapezoid.points[2].x-trapezoid.points[3].x,"toolbar trapezoid has parallel unequal bases");
+            mouse(WM_LBUTTONDOWN,trapezoid.to); mouse(WM_LBUTTONUP,{260,200});
+            require(c.marks[0].to.x==260 && c.marks[0].points[0].y==c.marks[0].points[1].y,"trapezoid resizes as a shape");
+            auto grip=ks::screenshotShapeRotationHandle(c.marks[0]);
+            auto rotated=ks::dragScreenshotMark(c.marks[0],ks::MarkPart::Rotation,grip,{280,135},320,240);
+            require(rotated.rotation!=0 && rotated.shape==ks::ScreenshotShape::Trapezoid,"trapezoid supports shape rotation");
+            SendMessageW(window,WM_COMMAND,12,0); require(c.marks[0].to.x==240,"undo trapezoid resize");
+            SendMessageW(window,WM_COMMAND,12,0); require(c.marks.empty(),"undo trapezoid creation");
+            SendMessageW(window,WM_COMMAND,18,0); require(c.marks[0].shape==ks::ScreenshotShape::Trapezoid,"redo trapezoid creation");
+            c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{};
+            SendMessageW(window,WM_COMMAND,21,0);
+        }
+        {
+            for(auto kind:{ks::ScreenshotShape::Rectangle,ks::ScreenshotShape::Circle,ks::ScreenshotShape::Ellipse,ks::ScreenshotShape::Triangle})
+            for(bool recognized:{false,true}) {
+                if(kind==ks::ScreenshotShape::Triangle && !recognized) continue;
+                ks::Mark shape{{100,90},{200,170},0}; shape.shape=kind; shape.ends=ks::LineEnds::None;
+                if(kind==ks::ScreenshotShape::Circle) shape.to.y=190;
+                if(recognized) shape.points=kind==ks::ScreenshotShape::Triangle?
+                    std::vector<POINT>{{150,90},{200,170},{100,170},{150,90}}:ks::shapeOutline(shape);
+                auto grip=ks::screenshotShapeRotationHandle(shape);
+                POINT center{(shape.from.x+shape.to.x)/2,(shape.from.y+shape.to.y)/2};
+                POINT right{center.x+center.y-grip.y,center.y};
+                auto rotated=ks::dragScreenshotMark(shape,ks::MarkPart::Rotation,grip,right,320,240);
+                require(std::abs(rotated.rotation-90)<.01 && rotated.from.x==shape.from.x && rotated.to.y==shape.to.y,
+                        "all native and recognized shapes rotate around their center");
+                auto corner=ks::rotateShapePoint(rotated,rotated.to);
+                require(ks::hitScreenshotMark(rotated,corner,4)==(kind==ks::ScreenshotShape::Triangle?ks::MarkPart::Vertex1:ks::MarkPart::End),"rotated resize handles remain hittable");
+                auto fixed=ks::rotateShapePoint(rotated,rotated.from);
+                auto resized=ks::dragScreenshotMark(rotated,ks::MarkPart::End,corner,{corner.x-15,corner.y+20},320,240);
+                auto stillFixed=ks::rotateShapePoint(resized,resized.from);
+                require(std::abs(stillFixed.x-fixed.x)<=1 && std::abs(stillFixed.y-fixed.y)<=1 && resized.rotation==90,
+                        "resizing rotated shapes keeps the opposite world corner fixed");
+                auto snapped=ks::dragScreenshotMark(shape,ks::MarkPart::Rotation,grip,{center.x+60,center.y-20},320,240,true);
+                require(std::abs(std::remainder(snapped.rotation,15))<.01,"Shift snaps shape rotation to 15 degrees");
+                auto cloned=ks::cloneScreenshotMark(rotated,{rotated},320,240);
+                require(cloned.rotation==rotated.rotation && cloned.shape==kind,"clone preserves shape rotation");
+                auto boundary=ks::shapeOutline(shape).front();
+                std::vector<ks::Mark> linked{shape,{{20,20},boundary,0}};
+                ks::linkScreenshotEndpoint(linked[1],false,boundary,linked,4);
+                require(linked[1].toLink.target!=0,"connector attaches to shape before rotation");
+                linked[0].rotation=90; ks::resolveScreenshotLinks(linked);
+                auto expected=ks::rotateShapePoint(linked[0],boundary);
+                require(std::abs(linked[1].to.x-expected.x)<=1 && std::abs(linked[1].to.y-expected.y)<=1,
+                        "connector follows rotated shape boundary");
+            }
+            ks::Mark shape{{100,90},{200,170},0}; shape.shape=ks::ScreenshotShape::Rectangle;
+            c.marks={shape}; c.selected=0;
+            auto mouse=[&](UINT message,POINT p) {
+                auto x=c.view.left+MulDiv(p.x,c.view.right-c.view.left,c.image->width);
+                auto y=c.view.top+MulDiv(p.y,c.view.bottom-c.view.top,c.image->height);
+                SendMessageW(window,message,message==WM_LBUTTONUP?0:MK_LBUTTON,MAKELPARAM(x,y));
+            };
+            auto grip=ks::screenshotShapeRotationHandle(shape,double(c.unit)*c.image->width/(c.view.right-c.view.left));
+            require(ks::markAt(c,grip).second==ks::MarkPart::Rotation,"shape rotation grip is distinct from thickness grip");
+            mouse(WM_LBUTTONDOWN,grip); mouse(WM_LBUTTONUP,{150+130-grip.y,130});
+            require(std::abs(c.marks[0].rotation-90)<1,"mouse rotation updates selected shape");
+            SendMessageW(window,WM_COMMAND,12,0); require(c.marks[0].rotation==0,"undo restores original shape orientation");
+            SendMessageW(window,WM_COMMAND,18,0); require(std::abs(c.marks[0].rotation-90)<1,"redo restores shape rotation");
+            c.selected=0;
+            ks::Surface rotatedPixels(320,240); PatBlt(rotatedPixels.dc,0,0,320,240,WHITENESS);
+            auto rendered=ks::decodeImage(ks::screenshotClip(rotatedPixels.dc,320,240,c.marks));
+            auto pixel=(100*320+190)*4;
+            require(rendered.bgra[pixel+2]==GetRValue(shape.color) && rendered.bgra[pixel+1]==GetGValue(shape.color),
+                    "export renders rotated shape at its new boundary");
+            POINT center{(c.canvas.left+c.canvas.right)/2,(c.canvas.top+c.canvas.bottom)/2};
+            ks::zoomCanvas(window,c,2,center);
+            grip=ks::screenshotShapeRotationHandle(c.marks[0],double(c.unit)*c.image->width/(c.view.right-c.view.left));
+            require(ks::markAt(c,grip).second==ks::MarkPart::Rotation,"rotation grip works on zoomed canvas");
+            ks::zoomCanvas(window,c,1,center,true);
+            c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{};
+        }
+        {
+            BYTE savedKeys[256]{},keys[256]{}; GetKeyboardState(savedKeys);
+            std::copy(savedKeys,savedKeys+256,keys); keys[VK_CONTROL]=0x80; SetKeyboardState(keys);
+            auto fit=c.view;
+            SendMessageW(window,WM_KEYDOWN,VK_OEM_PLUS,0);
+            require(c.zoom==1.25 && c.view.right-c.view.left>fit.right-fit.left,"Ctrl+plus zooms canvas");
+            SendMessageW(window,WM_KEYDOWN,VK_SUBTRACT,0);
+            require(std::abs(c.zoom-1)<.001,"Ctrl+numpad minus zooms out");
+            SendMessageW(window,WM_KEYDOWN,VK_ADD,0);
+            SendMessageW(window,WM_KEYDOWN,VK_OEM_MINUS,0);
+            require(std::abs(c.zoom-1)<.001,"both keyboard plus/minus variants work");
+            POINT center{(c.canvas.left+c.canvas.right)/2,(c.canvas.top+c.canvas.bottom)/2};
+            ks::zoomCanvas(window,c,4,center);
+            POINT anchor{center.x+12,center.y+8},screen=anchor; ClientToScreen(window,&screen);
+            auto before=ks::imagePoint(c,anchor,false); double zoom=c.zoom;
+            SendMessageW(window,WM_MOUSEWHEEL,MAKEWPARAM(MK_CONTROL,60),MAKELPARAM(screen.x,screen.y));
+            require(c.zoom==zoom,"partial wheel delta waits for a full step");
+            SendMessageW(window,WM_MOUSEWHEEL,MAKEWPARAM(MK_CONTROL,60),MAKELPARAM(screen.x,screen.y));
+            auto after=ks::imagePoint(c,anchor,false);
+            require(c.zoom>zoom && std::abs(before.x-after.x)<=1 && std::abs(before.y-after.y)<=1,
+                    "Ctrl+wheel zoom keeps image point under cursor");
+            require(!c.history.canUndo(),"zoom does not add image edits to undo history");
+            auto view=c.view;
+            SendMessageW(window,WM_MBUTTONDOWN,MK_MBUTTON,MAKELPARAM(center.x,center.y));
+            SendMessageW(window,WM_MOUSEMOVE,MK_MBUTTON,MAKELPARAM(center.x+15,center.y+10));
+            SendMessageW(window,WM_MBUTTONUP,0,MAKELPARAM(center.x+15,center.y+10));
+            require(c.view.left==view.left+15 && c.view.top==view.top+10 && !c.panning,"middle drag pans enlarged canvas");
+            keys[VK_CONTROL]=0; SetKeyboardState(keys);
+            auto a=ks::imagePoint(c,center),b=ks::imagePoint(c,{center.x+30,center.y+20});
+            SendMessageW(window,WM_LBUTTONDOWN,MK_LBUTTON,MAKELPARAM(center.x,center.y));
+            SendMessageW(window,WM_LBUTTONUP,0,MAKELPARAM(center.x+30,center.y+20));
+            require(c.marks.size()==1 && c.marks[0].from.x==a.x && c.marks[0].to.x==b.x && c.marks[0].to.y==b.y,
+                    "drawing after zoom and pan uses image coordinates");
+            auto original=c.marks[0];
+            keys[VK_CONTROL]=0x80; SetKeyboardState(keys);
+            SendMessageW(window,WM_KEYDOWN,'0',0);
+            require(c.zoom==1 && c.panX==0 && c.panY==0 && c.marks[0].from.x==original.from.x && c.marks[0].to.x==original.to.x,
+                    "Ctrl+0 resets view without transforming annotations");
+            ks::zoomCanvas(window,c,1e6,center); require(c.zoom==16,"zoom has upper bound");
+            ks::zoomCanvas(window,c,1e-6,center); require(c.zoom==.1,"zoom has lower bound");
+            SendMessageW(window,WM_KEYDOWN,'0',0); SetKeyboardState(savedKeys);
+            c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{};
+        }
         {
             BYTE savedKeys[256]{},keys[256]{}; GetKeyboardState(savedKeys);
             std::copy(savedKeys,savedKeys+256,keys); keys[VK_SHIFT]=0; SetKeyboardState(keys);
@@ -32,6 +254,57 @@ int main()
                 int y=c.view.top+MulDiv(p.y,c.view.bottom-c.view.top,c.image->height);
                 SendMessageW(window,message,(message==WM_LBUTTONUP?0:MK_LBUTTON)|(shift?MK_SHIFT:0),MAKELPARAM(x,y));
             };
+            mouse(WM_LBUTTONDOWN,{30,190});
+            for(int x=35;x<=200;x+=5) mouse(WM_MOUSEMOVE,{x,190+(x%10?2:-2)});
+            auto original=c.stroke.points;
+            mouse(WM_LBUTTONUP,c.stroke.to);
+            require(c.marks.size()==1,"improved stroke is one object");
+            require(!c.marks[0].freehand && c.marks[0].points.empty() &&
+                    c.marks[0].shape==ks::ScreenshotShape::None && !c.marks[0].isHighlight(),
+                    "near-straight pencil stroke becomes an editable line on mouse release");
+            require(c.marks[0].color==c.currentColor && c.marks[0].thickness==3 &&
+                    c.marks[0].style==c.lineStyle && c.marks[0].ends==c.freehandEnds,
+                    "line recognition preserves drawing style");
+            auto improved=c.marks.back().points;
+            SendMessageW(window,WM_COMMAND,12,0);
+            require(c.marks.size()==1 && c.marks.back().freehand && c.marks.back().points.size()==original.size() &&
+                    std::equal(original.begin(),original.end(),c.marks.back().points.begin(),
+                        [](POINT a,POINT b){return a.x==b.x && a.y==b.y;}),"first undo restores exact raw stroke");
+            SendMessageW(window,WM_COMMAND,12,0);
+            require(c.marks.empty(),"second undo removes stroke");
+            SendMessageW(window,WM_COMMAND,18,0); SendMessageW(window,WM_COMMAND,18,0);
+            require(c.marks.size()==1 && !c.marks.back().freehand && c.marks.back().points.size()==improved.size(),"redo restores improvement");
+            c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{};
+            mouse(WM_LBUTTONDOWN,{180,120});
+            for(int i=1;i<=120;++i) {
+                double a=i*2*3.141592653589793/120;
+                mouse(WM_MOUSEMOVE,{LONG(std::lround(130+50*std::cos(a))),LONG(std::lround(120+50*std::sin(a)))});
+            }
+            mouse(WM_LBUTTONUP,c.stroke.to);
+            require(c.marks.size()==1 && c.marks[0].shape==ks::ScreenshotShape::Circle &&
+                    !c.marks[0].freehand && !c.marks[0].isHighlight(),"recognized circle is a shape, not a pencil or highlight");
+            auto circle=c.marks[0];
+            require(ks::hitScreenshotMark(circle,circle.to,6)==ks::MarkPart::End,"recognized shape exposes bounding-box resize handle");
+            mouse(WM_LBUTTONDOWN,circle.to);
+            mouse(WM_MOUSEMOVE,{circle.to.x+30,circle.to.y+20});
+            mouse(WM_LBUTTONUP,{circle.to.x+30,circle.to.y+20});
+            require(c.marks[0].to.x>circle.to.x && c.marks[0].to.x-c.marks[0].from.x==c.marks[0].to.y-c.marks[0].from.y &&
+                    c.marks[0].points[0].x>circle.points[0].x,"dragging recognized circle handle scales the whole circle proportionally");
+            SendMessageW(window,WM_COMMAND,12,0);
+            require(c.marks[0].shape==ks::ScreenshotShape::Circle && c.marks[0].to.x==circle.to.x,"undo restores shape size");
+            SendMessageW(window,WM_COMMAND,12,0);
+            require(c.marks[0].freehand && c.marks[0].shape==ks::ScreenshotShape::None,"undo recognition restores editable pencil stroke");
+            SendMessageW(window,WM_COMMAND,18,0);
+            require(c.marks[0].shape==ks::ScreenshotShape::Circle,"redo restores shape type");
+            for(auto kind:{ks::ScreenshotShape::Rectangle,ks::ScreenshotShape::Ellipse,ks::ScreenshotShape::Triangle}) {
+                auto shape=circle; shape.shape=kind;
+                auto resized=ks::dragScreenshotMark(shape,ks::MarkPart::End,shape.to,{shape.to.x+50,shape.to.y+20},320,240);
+                require(resized.points[0].x!=shape.points[0].x && resized.points[24].y!=shape.points[24].y,
+                        "shape resize transforms all outline points in both axes");
+                auto moved=ks::cloneScreenshotMark(resized,{resized},320,240);
+                require(moved.shape==kind && !moved.isHighlight(),"clone preserves recognized shape type");
+            }
+            c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{};
             mouse(WM_LBUTTONDOWN,{40,40},true);
             mouse(WM_MOUSEMOVE,{100,50},true);
             require(c.stroke.to.x==100 && c.stroke.to.y==40,"Shift constrains pencil horizontally");

tests/stroke_improvement.h

@@ -0,0 +1,125 @@
+#pragma once
+inline void testStrokeImprovement() {
+    auto require=[](bool ok,const char *message){if(!ok) throw std::runtime_error(message);};
+    for(double angle:{0.0,.37,1.57079632679,2.8}) for(bool reverse:{false,true}) {
+        std::vector<POINT> p;
+        for(int i=0;i<=20;++i) {
+            double x=i*10,y=i==0 || i==20?0:(i%3)-1;
+            p.push_back({LONG(std::lround(300+x*std::cos(angle)-y*std::sin(angle))),
+                         LONG(std::lround(300+x*std::sin(angle)+y*std::cos(angle)))});
+        }
+        if(reverse) std::reverse(p.begin(),p.end());
+        bool line=false; ks::ScreenshotShape shape{};
+        auto result=ks::improveScreenshotStroke(p,&shape,&line);
+        require(line && shape==ks::ScreenshotShape::None && result.size()==2 &&
+                result.front().x==p.front().x && result.front().y==p.front().y &&
+                result.back().x==p.back().x && result.back().y==p.back().y,
+                "recognize noisy lines at arbitrary angles and preserve directed endpoints");
+    }
+    for(auto p:std::vector<std::vector<POINT>>{
+        {{0,0},{50,1},{100,0}}, {{0,0},{0,0},{50,0},{100,0}}}) {
+        bool line=false;
+        require(ks::improveScreenshotStroke(p,nullptr,&line).size()==2 && line,
+                "recognize sparsely sampled lines and repeated mouse positions");
+    }
+    for(auto p:std::vector<std::vector<POINT>>{
+        {{0,0},{8,1},{16,0}}, {{0,0},{50,0},{40,0},{80,0},{100,0}},
+        {{0,0},{25,8},{50,12},{75,8},{100,0}},
+        {{0,0},{50,0},{51,10},{52,0},{100,0}}, {{0,0},{0,0},{0,0}}}) {
+        bool line=true;
+        ks::improveScreenshotStroke(p,nullptr,&line);
+        require(!line,"do not straighten short strokes, retracing, curves, spikes or stationary input");
+    }
+    auto path=[](std::vector<POINT> corners) {
+        std::vector<POINT> p;
+        for(size_t i=1;i<corners.size();++i) for(int j=0;j<25;++j) {
+            double t=j/25.0;
+            p.push_back({LONG(std::lround(corners[i-1].x*(1-t)+corners[i].x*t)),
+                         LONG(std::lround(corners[i-1].y*(1-t)+corners[i].y*t))});
+        }
+        p.push_back(corners.back()); return p;
+    };
+    for(bool tilted:{false,true}) {
+        auto p=path({{40,40},{240,40},{240,140},{40,140},{40,40}});
+        if(tilted) for(auto &q:p) {double x=q.x,y=q.y;q={LONG(std::lround(x*.866-y*.5+100)),LONG(std::lround(x*.5+y*.866))};}
+        for(size_t i=1;i+1<p.size();++i) p[i].y+=int(i%3)-1;
+        auto result=ks::improveScreenshotStroke(p);
+        require(result.size()==5,"recognize noisy and tilted rectangles");
+        double ax=result[1].x-result[0].x,ay=result[1].y-result[0].y;
+        double bx=result[2].x-result[1].x,by=result[2].y-result[1].y;
+        require(std::abs(ax*bx+ay*by)<300,"rectangle has perpendicular sides");
+    }
+    auto triangle=ks::improveScreenshotStroke(path({{130,30},{240,180},{30,180},{130,30}}));
+    for(auto corners:std::vector<std::vector<POINT>>{
+        {{435,172},{455,135},{481,76},{514,78},{567,78},{605,76},{631,103},{652,135},{681,171},{609,172},{539,174},{435,172}},
+        {{531,311},{553,280},{582,235},{616,236},{672,233},{686,264},{693,287},{710,318},{640,314},{531,311}},
+        {{70,40},{160,40},{220,150},{20,150},{70,40}}})
+    for(double angle:{0.0,.6,2.2}) for(bool reverse:{false,true}) {
+        auto p=path(corners);
+        for(auto &q:p) { double x=q.x,y=q.y; q={LONG(std::lround(x*std::cos(angle)-y*std::sin(angle)+700)),
+            LONG(std::lround(x*std::sin(angle)+y*std::cos(angle)+700))}; }
+        if(reverse) std::reverse(p.begin(),p.end());
+        ks::ScreenshotShape kind{}; auto result=ks::improveScreenshotStroke(p,&kind);
+        require(kind==ks::ScreenshotShape::Trapezoid && result.size()==5,"recognize hand-drawn and tilted trapezoids");
+        double ax=result[1].x-result[0].x,ay=result[1].y-result[0].y;
+        double bx=result[3].x-result[2].x,by=result[3].y-result[2].y;
+        require(std::abs(ax*by-ay*bx)/(std::hypot(ax,ay)*std::hypot(bx,by))<.025,"recognized trapezoid bases are parallel");
+    }
+    // Approximate the reported skewed square, including its small closing gap.
+    auto unevenBox=path({{662,297},{663,213},{659,199},{659,181},{691,181},{718,189},
+                        {753,195},{786,195},{775,217},{771,249},{771,289},{766,313},
+                        {745,311},{716,304},{689,300},{671,300}});
+    for(double factor:{.5,1.0,2.5}) for(bool reverse:{false,true}) {
+        auto p=unevenBox;
+        for(auto &q:p) {q.x=LONG(std::lround((q.x-650)*factor+50));q.y=LONG(std::lround((q.y-170)*factor+50));}
+        if(reverse) std::reverse(p.begin(),p.end());
+        ks::ScreenshotShape kind{};
+        auto result=ks::improveScreenshotStroke(p,&kind);
+        require(kind==ks::ScreenshotShape::Rectangle && result.size()==5,"uneven square must not become a circle");
+    }
+    require(triangle.size()==4,"recognize triangle");
+    for(double ry:{50.0,90.0}) {
+        std::vector<POINT> p;
+        for(int i=0;i<=120;++i) {double a=i*2*3.141592653589793/120;
+            p.push_back({LONG(std::lround(150+90*std::cos(a))),LONG(std::lround(150+ry*std::sin(a)))});}
+        auto result=ks::improveScreenshotStroke(p);
+        require(result.size()==97 && result.front().x==result.back().x && result.front().y==result.back().y,
+                "recognize ellipse and circle as closed outlines");
+    }
+    auto open=path({{20,20},{200,20},{200,150},{60,150}});
+    // Hand-traced approximations of the uneven loops in the reported screenshot.
+    for(auto corners:std::vector<std::vector<POINT>>{
+        {{424,408},{449,407},{474,418},{487,439},{488,461},{475,485},{453,488},{432,479},{412,458},{410,435},{416,418},{431,409}},
+        {{352,474},{373,482},{389,501},{392,518},{378,529},{351,531},{331,519},{324,504},{326,486},{339,477},{352,474}},
+        {{246,236},{221,242},{192,256},{166,271},{151,289},{154,303},{172,316},{195,315},{226,305},{246,291},{250,272},{252,252},{246,236}}}) {
+        auto result=ks::improveScreenshotStroke(path(corners));
+        require(result.size()==97,"recognize uneven hand-drawn loops from screenshot");
+    }
+    for(double size:{35.0,100.0,300.0}) for(double aspect:{.5,1.0}) for(int direction:{-1,1}) {
+        std::vector<POINT> p;
+        for(int i=0;i<=120;++i) {
+            double a=direction*(.3+i*5.85/120),r=1+.07*std::sin(3*a)+.035*std::cos(7*a);
+            double x=size*r*std::cos(a),y=size*aspect*r*std::sin(a);
+            p.push_back({LONG(std::lround(500+x*.866-y*.5)),LONG(std::lround(500+x*.5+y*.866))});
+        }
+        require(ks::improveScreenshotStroke(p).size()==97,"recognize wobbly tilted ovals with closing gaps at different sizes");
+    }
+    for(double turns:{.72,1.8}) {
+        std::vector<POINT> p;
+        for(int i=0;i<=120;++i) {double a=i*turns*2*3.141592653589793/120;
+            p.push_back({LONG(std::lround(150+90*std::cos(a))),LONG(std::lround(150+70*std::sin(a)))});}
+        auto result=ks::improveScreenshotStroke(p);
+        require(result.size()!=97,"do not close broad arcs or repeated loops into ovals");
+    }
+    auto smoothed=ks::improveScreenshotStroke(open);
+    require(smoothed.size()>5 && smoothed.front().x==20 && smoothed.back().x==60,"open outline stays open");
+    auto scribble=path({{20,20},{200,150},{200,20},{20,150},{20,20}});
+    require(ks::improveScreenshotStroke(scribble).size()>97,"crossed scribble is not a shape");
+    require(ks::improveScreenshotStroke({{1,1},{1,1},{1,1},{1,1},{1,1}}).empty(),"stationary stroke unchanged");
+    std::vector<POINT> jitter;
+    for(int i=0;i<=100;++i) jitter.push_back({20+i*2,100+(i%2?2:-2)});
+    auto smooth=ks::improveScreenshotStroke(jitter);
+    double deviation=0; for(auto p:smooth) deviation+=std::abs(p.y-100);
+    require(deviation/smooth.size()<1.5 && smooth.front().y==jitter.front().y && smooth.back().y==jitter.back().y,
+            "smoothing reduces jitter and preserves endpoints");
+}

tests/sync.cpp

@@ -0,0 +1,328 @@
+#include "sync.h"
+#include "json.hpp"
+#include <iostream>
+using namespace ks;
+using Json = nlohmann::json;
+namespace
+{
+int checks{};
+void require(bool condition, const char *message)
+{
+    if (!condition) throw std::runtime_error(message);
+    ++checks;
+}
+template<class F> void rejects(F f, const char *message)
+{
+    bool rejected = false;
+    try { f(); } catch (const std::exception &) { rejected = true; }
+    require(rejected, message);
+}
+Bytes bytes(const Json &j) { auto s = j.dump(); return {s.begin(), s.end()}; }
+Json parse(const Bytes &b) { return Json::parse(b.begin(), b.end()); }
+struct FakeProvider : SyncProvider
+{
+    SyncDocument remote;
+    int writes{};
+    bool race{};
+    SyncDocument read() override { return remote; }
+    uint64_t write(const Bytes &b, uint64_t expected) override
+    {
+        if (race) ++remote.revision;
+        if (expected != remote.revision) throw std::runtime_error("CAS conflict");
+        ++writes; remote = {remote.revision + 1, b}; return remote.revision;
+    }
+};
+}
+int main()
+{
+    auto root = std::filesystem::temp_directory_path() / (L"ks-sync-test-" + std::to_wstring(GetCurrentProcessId()));
+    try
+    {
+        std::filesystem::create_directories(root);
+        require(!syncVisible(root), "hidden without opt-in file");
+        require(!loadSyncConfig(root).enabled, "disabled by default");
+        SyncConfig config; config.server = L"https://bao.example.com"; config.username = L"person"; config.enabled = true;
+        validateSyncConfig(config);
+        for (const auto *server : {L"http://bao.example.com", L"https://user:pass@bao.example.com", L"https://bao.example.com/x", L"https://bao.example.com?x=1"})
+        {
+            auto invalid = config; invalid.server = server;
+            rejects([&] { validateSyncConfig(invalid); }, "reject unsafe endpoint");
+        }
+        auto invalid = config; invalid.path = L"../other";
+        rejects([&] { validateSyncConfig(invalid); }, "reject traversal");
+        invalid = config; invalid.provider = L"unknown";
+        rejects([&] { validateSyncConfig(invalid); }, "reject unsupported provider");
+        saveSyncConfig(root, config);
+        require(syncVisible(root) && loadSyncConfig(root) == config, "connection round trip");
+        auto partialConfig = config; partialConfig.keepLocalLayouts = true;
+        saveSyncConfig(root, partialConfig);
+        require(loadSyncConfig(root).keepLocalLayouts, "partial sync mode survives restart");
+        saveSyncConfig(root, config);
+        auto rawConfig = parse(readFile(root / L"sync.json", 16384));
+        require(!rawConfig.contains("password") && !rawConfig.contains("token"), "no secrets in config");
+        Settings local;
+        local.autostart = true; local.elevatedAutostart = true; local.tesseractPath = L"C:\\private\\tesseract.exe";
+        local.history = false;
+        local.snippets.push_back({L"test", L"private snippet"});
+        auto base = sharedSyncSettings(local);
+        Settings ordered = local, reordered = local;
+        ordered.directIds = {L"00000409", L"00000422"}; ordered.direct = {L"Ctrl+1", L"Ctrl+2"};
+        reordered.directIds = {L"00000422", L"00000409"}; reordered.direct = {L"Ctrl+2", L"Ctrl+1"};
+        require(sharedSyncSettings(ordered) == sharedSyncSettings(reordered), "layout enumeration does not cause sync churn");
+        auto j = parse(base);
+        require(!j.contains("startWithSystem") && !j.contains("tesseractPath") && !j.contains("historyEnabled"), "local-only fields excluded");
+        auto restored = restoreSyncSettings(base, local, {});
+        require(restored.autostart && restored.elevatedAutostart && !restored.history && restored.tesseractPath == local.tesseractPath, "preserve device settings");
+        auto hostile = j; hostile["startWithSystem"] = false;
+        rejects([&] { restoreSyncSettings(bytes(hostile), local, {}); }, "reject injected device setting");
+        hostile = j; hostile["schemaVersion"] = 2;
+        rejects([&] { restoreSyncSettings(bytes(hostile), local, {}); }, "reject future schema");
+        hostile = j; hostile["layouts"] = Json::array({"00000422"});
+        rejects([&] { restoreSyncSettings(bytes(hostile), local, {}); }, "missing layouts block destructive normalization");
+        auto left = j, right = j;
+        left["convertLastWord"] = false; right["switchSystemLayout"] = false;
+        auto merged = parse(mergeSyncSettings(base, bytes(left), bytes(right)));
+        require(merged["convertLastWord"] == false && merged["switchSystemLayout"] == false, "merge independent edits");
+        left = right = j; left["autoCorrectMinLength"] = 4; right["autoCorrectMinLength"] = 5;
+        rejects([&] { mergeSyncSettings(base, bytes(left), bytes(right)); }, "same field conflict");
+        left = right = j; left["snippets"].push_back({{"trigger", "aaa"}, {"text", "one"}});
+        right["snippets"].push_back({{"trigger", "bbb"}, {"text", "two"}});
+        require(parse(mergeSyncSettings(base, bytes(left), bytes(right)))["snippets"].size() == 3, "independent snippet additions merge");
+        require(parse(mergeSyncSettings({}, bytes(left), base))["snippets"].size() == 2,
+                "first sync merges independent additions without choosing a whole profile");
+        require(parse(mergeSyncSettings({}, base, base)) == j, "identical first sync safe");
+        {
+            auto l = j, r = j;
+            l["autoCorrectMinLength"] = 4; r["autoCorrectMinLength"] = 5;
+            l["autoCorrectNever"].push_back("localword");
+            r["autoCorrectNever"].push_back("remoteword");
+            auto plan = mergeSyncProfile({}, bytes(l), bytes(r));
+            require(plan.conflicts.size() == 1 && parse(plan.local)["autoCorrectNever"].size() == 2 &&
+                    parse(plan.remote)["autoCorrectNever"].size() == 2,
+                    "first sync merges lists while preserving scalar conflicts");
+            require(parse(plan.local)["autoCorrectMinLength"] == 4 && parse(plan.remote)["autoCorrectMinLength"] == 5,
+                    "first sync never guesses between different scalar values");
+            auto again = mergeSyncProfile(plan.base, plan.local, plan.remote);
+            require(again.conflicts.size() == 1, "first-sync conflicts survive saving the ancestor");
+            auto resolved = mergeSyncProfile(plan.base, plan.local, plan.remote, {{plan.conflicts[0], false}});
+            require(resolved.conflicts.empty() && parse(resolved.local)["autoCorrectMinLength"] == 5,
+                    "first-sync conflict can be resolved independently");
+        }
+        require(SyncIntervalMs == 600000, "background interval is ten minutes");
+        {
+            auto l = j, r = j;
+            l["autoCorrectReplacements"]["helo"] = "hello";
+            r["autoCorrectReplacements"]["wrold"] = "world";
+            auto paired = mergeSyncSettings(base, bytes(l), bytes(r));
+            require(parse(paired)["autoCorrectReplacements"].size() == 2, "independent replacement pairs merge");
+            l = r = parse(paired);
+            l["autoCorrectReplacements"].erase("helo");
+            r["autoCorrectReplacements"]["wrold"] = "worlds";
+            auto removed = mergeSyncSettings(paired, bytes(l), bytes(r));
+            auto restored = restoreSyncSettings(removed, local, {});
+            require(restored.autoReplacements.size() == 1 && restored.autoReplacements.at(L"wrold") == L"worlds",
+                    "replacement deletion merges with an independent edit and remains loadable");
+            r["autoCorrectReplacements"]["helo"] = "help";
+            require(mergeSyncProfile(paired, bytes(l), bytes(r)).conflicts.size() == 1,
+                    "replacement deletion versus edit is a conflict");
+            auto legacy = j;
+            for (auto key : {"autoCorrectReplace", "autoCorrectTypos", "autoCorrectReplacements"}) legacy.erase(key);
+            auto migrated = restoreSyncSettings(bytes(legacy), local, {});
+            require(!migrated.autoReplace && !migrated.autoTypos && migrated.autoReplacements.empty(),
+                    "older synchronized profiles default new typo modes off");
+        }
+        {
+            auto l = j, r = j;
+            l["autoCorrectMinLength"] = 4; r["autoCorrectMinLength"] = 5;
+            l["convertLastWord"] = false; r["switchSystemLayout"] = false;
+            auto plan = mergeSyncProfile(base, bytes(l), bytes(r));
+            require(plan.conflicts.size() == 1, "one conflict reported independently");
+            require(parse(plan.local)["switchSystemLayout"] == false && parse(plan.remote)["convertLastWord"] == false,
+                "nonconflicting changes reach both copies");
+            require(parse(plan.local)["autoCorrectMinLength"] == 4 && parse(plan.remote)["autoCorrectMinLength"] == 5,
+                "unresolved scalar retains both values");
+            require(parse(plan.base)["autoCorrectMinLength"] == j["autoCorrectMinLength"], "ancestor retained for unresolved setting");
+            saveSyncBase(root, config, plan.base);
+            auto again = mergeSyncProfile(loadSyncBase(root, config), plan.local, plan.remote);
+            require(again.conflicts.size() == 1, "conflict survives restart checkpoint");
+            auto choice = SyncChoice{plan.conflicts.front(), true};
+            auto resolved = mergeSyncProfile(plan.base, plan.local, plan.remote, {choice});
+            require(resolved.conflicts.empty() && parse(resolved.remote)["autoCorrectMinLength"] == 4,
+                "resolve only selected setting");
+            require(parse(resolved.remote)["switchSystemLayout"] == false, "choice preserves independent server change");
+            auto changed = parse(plan.remote); changed["autoCorrectMinLength"] = 6;
+            require(mergeSyncProfile(plan.base, plan.local, bytes(changed), {choice}).conflicts.size() == 1,
+                "stale conflict choice never overwrites new server value");
+            FakeProvider partial; partial.remote = {7, bytes(r)};
+            auto result = synchronize(partial, base, bytes(l), SyncAction::Automatic);
+            require(result.success && result.conflicts.size() == 1 && partial.writes == 1,
+                "partial synchronization commits independent fields with CAS");
+            auto encoded = encodeSyncChoices({choice});
+            require(decodeSyncChoices(encoded).front().conflict.key == choice.conflict.key, "choice IPC round trip");
+        }
+        {
+            auto id = j["snippets"][0]["id"].get<std::string>();
+            auto l = j, r = j;
+            l["snippets"][0]["trigger"] = "renamed";
+            r["snippets"][0]["text"] = "edited remotely";
+            auto merged = parse(mergeSyncSettings(base, bytes(l), bytes(r)));
+            require(merged["snippets"][0]["id"] == id && merged["snippets"][0]["trigger"] == "renamed" &&
+                merged["snippets"][0]["text"] == "edited remotely", "stable ID merges rename and text edit");
+            l = r = j; l["snippets"] = Json::array(); l["snippetTombstones"] = Json::array({id});
+            auto deletion = mergeSyncProfile(base, bytes(l), bytes(r));
+            require(deletion.conflicts.empty() && parse(deletion.remote)["snippets"].empty(), "delete beats unchanged snippet");
+            require(parse(deletion.remote)["snippetTombstones"] == Json::array({id}), "deletion marker retained");
+            auto offline = mergeSyncProfile(base, bytes(r), deletion.remote);
+            require(offline.conflicts.empty() && parse(offline.local)["snippets"].empty(), "offline copy cannot resurrect deletion");
+            r["snippets"][0]["text"] = "offline edit";
+            auto conflict = mergeSyncProfile(base, bytes(l), bytes(r));
+            require(conflict.conflicts.size() == 1, "delete versus edit is one snippet conflict");
+            auto remove = mergeSyncProfile(conflict.base, conflict.local, conflict.remote, {{conflict.conflicts[0], true}});
+            require(remove.conflicts.empty() && parse(remove.remote)["snippets"].empty(), "choose deletion");
+            auto keep = mergeSyncProfile(conflict.base, conflict.local, conflict.remote, {{conflict.conflicts[0], false}});
+            require(keep.conflicts.empty() && parse(keep.local)["snippetTombstones"].empty() &&
+                parse(keep.local)["snippets"][0]["text"] == "offline edit", "choose edited snippet removes tombstone");
+            require(mergeSyncProfile(base, bytes(l), bytes(l)).conflicts.empty(), "both delete converges");
+            auto legacy = j; legacy.erase("snippetTombstones"); legacy["snippets"][0].erase("id");
+            auto migrated = parse(mergeSyncSettings(bytes(legacy), base, bytes(legacy)));
+            require(migrated["snippets"][0]["id"] == id, "legacy profiles migrate to identical IDs");
+            auto roundtrip = decodeSettings(encodeSettings(restored), {});
+            require(snippetId(roundtrip.snippets.front()) == wide(id), "ID survives settings serialization");
+            require(newSnippetId() != newSnippetId(), "new snippet IDs are unique");
+        }
+        {
+            auto l = j, r = j;
+            l["snippets"].push_back({{"id", "new-a"}, {"trigger", "same"}, {"text", "A"}});
+            r["snippets"].push_back({{"id", "new-b"}, {"trigger", "same"}, {"text", "B"}});
+            auto collision = mergeSyncProfile(base, bytes(l), bytes(r));
+            require(collision.conflicts.size() == 2, "duplicate new triggers expose individual choices");
+            auto resolved = mergeSyncProfile(collision.base, collision.local, collision.remote,
+                {{collision.conflicts[0], true}, {collision.conflicts[1], true}});
+            require(resolved.conflicts.empty() && parse(resolved.remote)["snippets"].size() == 2, "choose one of colliding additions");
+            l = r = j; l["toggleHotkey"] = "Ctrl+Alt+F11"; r["caseHotkey"] = "Ctrl+Alt+F11";
+            require(mergeSyncProfile(base, bytes(l), bytes(r)).conflicts.size() == 2, "cross-field shortcut collisions exposed");
+            l = r = j; l["excludedApps"].push_back("local-app"); r["excludedApps"].push_back("remote-app");
+            require(parse(mergeSyncSettings(base, bytes(l), bytes(r)))["excludedApps"].size() == j["excludedApps"].size() + 2,
+                "independent exclusion edits merge");
+        }
+        FakeProvider provider;
+        rejects([&] { synchronize(provider, {}, base, SyncAction::Automatic); }, "empty server never auto-populated");
+        auto result = synchronize(provider, {}, base, SyncAction::Upload);
+        require(result.revision == 1 && provider.writes == 1, "initial upload CAS zero");
+        result = synchronize(provider, base, base, SyncAction::Automatic);
+        require(provider.writes == 1 && result.revision == 1, "no-op avoids versions");
+        result = synchronize(provider, base, bytes(left), SyncAction::Download);
+        require(parse(result.settings) == parse(base) && provider.writes == 1, "download never writes");
+        provider.race = true;
+        rejects([&] { synchronize(provider, base, bytes(left), SyncAction::Upload); }, "racing writer protected");
+        require(provider.writes == 1 && provider.remote.settings == base, "CAS failure preserves remote");
+        provider.race = false;
+        {
+            auto remoteProfile = j;
+            remoteProfile["layouts"] = Json::array({"win:00000422"});
+            remoteProfile["layoutHotkeys"] = Json::array({{{"layoutId", "win:00000422"}, {"hotkey", "Ctrl+Alt+9"}}});
+            remoteProfile["autoCorrectNever"].push_back("remoteword");
+            FakeProvider partial;
+            partial.remote = {3, bytes(remoteProfile)};
+            auto validate = [&](const Bytes &b) { restoreSyncSettings(b, local, {}, true); };
+            auto result = synchronize(partial, {}, base, SyncAction::Automatic, validate, {}, true);
+            auto restored = restoreSyncSettings(result.settings, local, {}, true);
+            require(restored.cycle == local.cycle && restored.direct == local.direct &&
+                    restored.autoNever == std::vector<std::wstring>{L"remoteword"},
+                    "partial sync restores other settings and keeps local layout configuration");
+            auto next = sharedSyncSettings(restored);
+            result = synchronize(partial, result.base, next, SyncAction::Automatic, validate, {}, true);
+            require(parse(partial.remote.settings)["layouts"] == remoteProfile["layouts"] &&
+                    parse(partial.remote.settings)["layoutHotkeys"] == remoteProfile["layoutHotkeys"],
+                    "repeated partial sync never deletes unavailable server layouts or shortcuts");
+            auto changed = parse(next); changed["autoCorrectMinLength"] = 7;
+            result = synchronize(partial, result.base, bytes(changed), SyncAction::Upload, validate, {}, true);
+            require(parse(partial.remote.settings)["autoCorrectMinLength"] == 7 &&
+                    parse(partial.remote.settings)["layoutHotkeys"] == remoteProfile["layoutHotkeys"],
+                    "explicit partial upload preserves server layouts too");
+            auto downloaded = synchronize(partial, result.base, base, SyncAction::Download, validate, {}, true);
+            auto downloadedSettings = restoreSyncSettings(downloaded.settings, local, {}, true);
+            require(downloadedSettings.autoMinLength == 7 && downloadedSettings.cycle == local.cycle &&
+                    downloadedSettings.direct == local.direct, "partial Download applies other settings without replacing local layouts");
+            try { restoreSyncSettings(bytes(remoteProfile), local, {}); require(false, "full sync must identify missing layouts"); }
+            catch (const std::runtime_error &e) {
+                std::string message = e.what();
+                require(message.find("win:00000422") != message.npos && message.find("Keep this PC's layouts") != message.npos,
+                        "missing-layout error identifies IDs and offers partial sync");
+            }
+        }
+        rejects([&] { synchronize(provider, base, bytes(left), SyncAction::Upload,
+            [](const Bytes &) { throw std::runtime_error("invalid"); }); }, "validate before upload");
+        require(provider.writes == 1, "invalid data not uploaded");
+        saveSyncBase(root, config, base);
+        require(parse(loadSyncBase(root, config)) == j, "encrypted baseline round trip");
+        auto other = config; other.path = L"other/settings";
+        require(loadSyncBase(root, other).empty(), "baseline bound to connection");
+        auto encrypted = readFile(root / L"sync-base.bin", 1024 * 1024);
+        std::string disk(encrypted.begin(), encrypted.end());
+        require(disk.find("private snippet") == disk.npos, "baseline encrypted on disk");
+        // Exercise real Credential Manager with an isolated test target, never a user endpoint.
+        config.username = L"ks-sync-test-" + std::to_wstring(GetCurrentProcessId());
+        saveSyncPassword(config, L"test-only-password");
+        int logins{}, revokes{}, reads{}, writes{};
+        unsigned readStatus = 200, writeStatus = 200;
+        bool deleted = false;
+        auto transport = [&](const std::wstring &method, const std::wstring &path,
+            const std::wstring &token, const Bytes &body) -> SyncHttpResponse {
+            if (path == L"/v1/auth/userpass/login/" + config.username)
+            {
+                require(method == L"POST" && token.empty(), "login route and no bearer token");
+                require(parse(body)["password"] == "test-only-password", "password sourced from credential manager");
+                ++logins;
+                return {200, bytes({{"auth", {{"client_token", "test-token"}}}})};
+            }
+            require(token == L"test-token", "authenticated requests use returned token");
+            if (path == L"/v1/auth/token/revoke-self")
+            {
+                require(method == L"POST", "revoke method"); ++revokes; return {204, {}};
+            }
+            require(path == L"/v1/kswitcher/data/personal/settings", "KV v2 data route");
+            if (method == L"GET")
+            {
+                ++reads;
+                if (readStatus != 200 && !deleted) return {readStatus, bytes({{"errors", Json::array()}})};
+                return {readStatus, bytes({{"data", {
+                    {"metadata", {{"version", 7}, {"deletion_time", deleted ? "2026-01-01" : ""}, {"destroyed", false}}},
+                    {"data", {{"syncSchema", 1}, {"settings", j}}}}}})};
+            }
+            require(method == L"POST", "write method");
+            auto request = parse(body);
+            require(request["options"]["cas"] == 7, "write includes exact CAS revision");
+            require(request["data"]["syncSchema"] == 2 && request["data"]["settings"] == j, "versioned settings envelope");
+            ++writes;
+            return {writeStatus, bytes({{"data", {{"version", 8}}}})};
+        };
+        {
+            auto bao = makeSyncProvider(config, transport);
+            auto doc = bao->read();
+            require(doc.revision == 7 && parse(doc.settings) == j, "read protocol response");
+            require(bao->write(base, 7) == 8, "write protocol response");
+            readStatus = 404;
+            require(bao->read().revision == 0, "missing profile");
+            deleted = true;
+            rejects([&] { bao->read(); }, "soft deleted is not treated as absent");
+            deleted = false; readStatus = 403;
+            rejects([&] { bao->read(); }, "permission denied is not absent");
+            readStatus = 302;
+            rejects([&] { bao->read(); }, "redirect response rejected");
+            writeStatus = 400;
+            rejects([&] { bao->write(base, 7); }, "server CAS refusal propagated");
+        }
+        require(logins == 1 && revokes == 1 && reads == 5 && writes == 2, "temporary login lifecycle");
+        forgetSyncPassword(config); forgetSyncPassword(config);
+        ++checks;
+        std::filesystem::remove_all(root);
+        std::cout << checks << " sync checks passed\n";
+        return 0;
+    }
+    catch (const std::exception &e)
+    {
+        std::cerr << e.what() << "\n";
+        return 1;
+    }
+}

tests/tests.cpp

@@ -111,8 +111,8 @@ int main(int argc, char **argv)
         require(diagnostics.record(L"later-failure", true, 30500).find(L"expired-context") == std::wstring::npos,
                 "context expires after thirty seconds");
         diagnostics.record(L"oldest-context", false, 30600);
-        for (int i = 0; i < 40; ++i)
+        for (int i = 0; i < 128; ++i)
-            diagnostics.record(L"bounded-context", false, 30600 + i);
+            diagnostics.record(L"bounded-context", false, 30600);
         require(diagnostics.record(L"bounded-failure", true, 30700).find(L"oldest-context") == std::wstring::npos,
                 "context buffer has a fixed size");
         diagnostics.record(L"disabled-context", false, 30800);
@@ -192,11 +192,38 @@ int main(int argc, char **argv)
         require(ks::convert(L"hello привет", en, ru) == L"руддщ привет", "mixed text preserves target words");
         require(ks::convert(L"htdm.dftim", en, ru) == L"ревьюваешь", "punctuation in words");
         std::vector<ks::Layout> layouts{en, ru, uk};
+        ks::Run suffixRun;
+        suffixRun.keys = L"snipping ";
+        require(suffixRun.matchSuffix(L"зштп ", layouts, en) >= 0,
+                "recent Cyrillic suffix matches physical keys across layouts");
+        require(suffixRun.matchSuffix(L"ping ", layouts, en) == 0,
+                "recent English suffix matches physical keys");
+        require(suffixRun.matchSuffix(L"other", layouts, en) < 0 &&
+                    suffixRun.matchSuffix(L"", layouts, en) < 0 &&
+                    suffixRun.matchSuffix(L"snipping ", layouts, en) < 0,
+                "suffix recovery rejects unrelated, empty and complete ranges");
+        suffixRun.overflow = true;
+        require(suffixRun.matchSuffix(L"зштп ", layouts, en) < 0,
+                "suffix recovery rejects overflowed tracking");
+        suffixRun.overflow = false;
+        suffixRun.keys = L"LinkedIn ";
+        require(suffixRun.matchSuffix(L"лувШт ", layouts, en) >= 0,
+                "ChatGPT partial CamelCase selection matches tracked physical suffix");
+        require(suffixRun.match(L"ДштлувШт ", layouts, en) >= 0 &&
+                    suffixRun.match(L"лувШт ", layouts, en) < 0,
+                "CamelCase conversion still requires the complete tracked text after recovery");
         ks::AutoCorrector corrector;
         ks::Settings autoSettings;
         require(!autoSettings.autoCorrect, "auto-correction defaults off");
         autoSettings.cycle = {L"en", L"uk"};
         corrector.configure(L"dictionaries", autoSettings.autoLanguages);
+        {
+            auto options = autoSettings;
+            options.autoTypos = true;
+            auto typo = corrector.suggest(L"првиіт ", 2, layouts, options);
+            require(typo && typo->text == L"привіт " && typo->target == 2,
+                    "bundled Ukrainian dictionary corrects a common transposition");
+        }
         auto suggested = corrector.suggest(L"ghbdsn ", 0, layouts, autoSettings);
         require(suggested && suggested->text == L"привіт " && suggested->target == 2,
                 "dictionary corrects Ukrainian and retains trailing space");
@@ -291,6 +318,14 @@ int main(int argc, char **argv)
             options.autoLanguages = {L"en", L"uk", L"ru"};
             options.cycle = {L"en", L"uk", L"ru"};
             supplemental.configure(L"dictionaries", options.autoLanguages);
+            auto current = supplemental.suggest(L"Gjnjxys ", 0, layouts, options);
+            require(current && current->text == L"Поточні " && current->target == 2,
+                    "reported title-case Ukrainian word corrects with all three dictionaries enabled");
+            current = supplemental.suggest(L"Поточны ", 1, layouts, options);
+            require(current && current->text == L"Поточні " && current->target == 2,
+                    "reported Ukrainian word corrects from Russian layout");
+            require(!supplemental.suggest(L"Поточні ", 2, layouts, options),
+                    "correct Ukrainian word remains unchanged");
             for (auto [typed, expected] : {std::pair{L"ntcn ", L"тест "}, std::pair{L"vfkj ", L"мало "}})
             {
                 auto shared = supplemental.suggest(typed, 0, layouts, options);
@@ -307,6 +342,8 @@ int main(int argc, char **argv)
             require(!supplemental.suggest(L"релиз ", 1, layouts, options),
                     "valid Russian release word stays unchanged");
             options.autoMaxRank = 50000;
+            require(!supplemental.suggest(L"Gjnjxys ", 0, layouts, options),
+                    "supplemental current word respects explicit frequency limit");
             require(!supplemental.suggest(L"релыз ", 1, layouts, options),
                     "supplemental vocabulary respects explicit frequency limit");
             options.autoWords[L"uk"] = {L"релізик"};
@@ -337,6 +374,22 @@ int main(int argc, char **argv)
         require(ks::convertTo(L"ghbdtn", layouts, 1, 0) == L"привет", "hint conversion");
         require(ks::convertTo(L"привет", layouts, 1, 1) == L"привет", "same source is unchanged");
         require(ks::convertTo(L"?", layouts, 1, 0) == L",", "punctuation conversion");
+        require(ks::nextConversionLayout(L"рф", layouts, {0, 1, 2}, 1) == 0 &&
+                    ks::convertTo(L"рф", layouts, 0, 1) == L"ha",
+                "cycle skips unchanged Russian to Ukrainian and wraps to English");
+        require(ks::nextConversionLayout(L"шььш", layouts, {0, 2, 1}, 2) == 0 &&
+                    ks::convertTo(L"шььш", layouts, 0, 2) == L"immi",
+                "cycle skips unchanged Ukrainian to Russian");
+        require(ks::nextConversionLayout(L"і", layouts, {0, 2, 1}, 2) == 1,
+                "cycle keeps the next language when text changes");
+        require(ks::nextConversionLayout(L"ha", layouts, {0, 1, 2}, 0) == 1,
+                "cycle preserves configured order for changed text");
+        require(ks::nextConversionLayout(L"рф", layouts, {1, 2}, 1) == 2,
+                "cycle does not use disabled English when all candidates are unchanged");
+        require(ks::nextConversionLayout(L"123 ", layouts, {0, 1, 2}, 0) == 1,
+                "unchanged digits finish after a bounded cycle");
+        require(ks::nextConversionLayout(L"рф", layouts, {2, 0}, 1) == 0,
+                "source outside cycle still skips unchanged candidates");
         require(ks::cycleCase(L"hello world") == L"Hello World", "title case");
         require(ks::cycleCase(L"Hello World") == L"HELLO WORLD", "upper case");
         require(ks::cycleCase(L"ПРИВІТ") == L"привіт", "Unicode lower case");
@@ -451,6 +504,45 @@ int main(int argc, char **argv)
             auto correction = edited.suggest(L"руддщ ", 2, layouts, options);
             require(correction && correction->text == L"hello ",
                     "unsorted dictionaries and duplicates load using lowest duplicate rank");
+            require(!edited.suggest(L"hlelo ", 0, layouts, options), "spelling correction defaults off");
+            options.autoTypos = true;
+            for (auto typo : {L"hlelo ", L"helo ", L"helllo ", L"hezlo "})
+            {
+                correction = edited.suggest(typo, 0, layouts, options);
+                require(correction && correction->text == L"hello " && correction->target == 0,
+                        "single transposition, deletion, insertion and substitution retain the source layout");
+            }
+            correction = edited.suggest(L"(Hlelo), ", 0, layouts, options);
+            require(correction && correction->text == L"(Hello), ", "typos retain case and punctuation");
+            for (auto text : {L"hello ", L"HLELO ", L"hLelo ", L"h3llo ", L"h.llo ", L"hlo ", L"hello@example.com "})
+                require(!edited.suggest(text, 0, layouts, options), "known or unsafe typo input is unchanged");
+            options.autoWords[L"en"] = {L"hella"};
+            require(!edited.suggest(L"hell ", 0, layouts, options), "personal dictionary alternatives create ambiguity");
+            options.autoWords.clear();
+            options.autoReplacements = {{L"hlelo", L"greeting"}, {L"hello", L"greetings"}, {L"првиіт", L"привіт"}};
+            options.autoReplace = true;
+            correction = edited.suggest(L"Hlelo! ", 0, layouts, options);
+            require(correction && correction->text == L"Greeting! ", "explicit replacements override spelling guesses");
+            correction = edited.suggest(L"hello ", 0, layouts, options);
+            require(correction && correction->text == L"greetings ", "explicit replacements can override known words");
+            correction = edited.suggest(L"Првиіт ", 2, layouts, options);
+            require(correction && correction->text == L"Привіт " && correction->target == 2,
+                    "Ukrainian replacements work without dictionary membership");
+            options.autoNever = {L"hlelo"};
+            require(!edited.suggest(L"hlelo ", 0, layouts, options), "never-correct overrides explicit pairs");
+            options.autoNever.clear();
+            edited.reject(L"(Hlelo)! ", options);
+            require(!edited.suggest(L"hlelo ", 0, layouts, options), "undo rejection suppresses custom replacements");
+            options.autoReplace = false;
+            options.autoWords[L"uk"] = {L"привіт"};
+            correction = edited.suggest(L"првиіт ", 2, layouts, options);
+            require(correction && correction->text == L"привіт ", "Ukrainian personal words are typo targets");
+            options.cycle = {L"en"};
+            require(!edited.suggest(L"првиіт ", 2, layouts, options), "disabled source layouts do not correct typos");
+            put(L"en.txt", L"hello\t1\nhella\t99999\n");
+            ks::AutoCorrector ambiguous;
+            ambiguous.configure(folder, {L"en", L"uk"});
+            require(!ambiguous.suggest(L"hell ", 0, layouts, options), "frequency filter does not conceal ambiguous typo targets");
         }
         ks::Pixels pixels{2, 1, {10, 20, 30, 255, 40, 50, 60, 255}};
         ks::Clip firstImage{{ks::imageDib(pixels), {0, L"Ole Private Data", {1, 2, 3}}}};
@@ -496,6 +588,8 @@ int main(int argc, char **argv)
         settings.writeLog = false;
         settings.elevatedAutostart = true;
         settings.autoCorrect = true;
+        settings.autoReplace = settings.autoTypos = true;
+        settings.autoReplacements = {{L"првиіт", L"привіт"}, {L"helo", L"hello"}};
         settings.autoMaxRank = 10000;
         settings.autoMinLength = 5;
         settings.autoPrefixChars = L"(#";
@@ -508,6 +602,14 @@ int main(int argc, char **argv)
         ks::saveSettings(temp / L"settings.json", settings);
         auto restored = ks::loadSettings(temp / L"settings.json", {});
         require(restored.autoWords == settings.autoWords, "personal dictionaries survive settings roundtrip");
+        require(restored.autoReplace && restored.autoTypos && restored.autoReplacements == settings.autoReplacements,
+                "typo options and Unicode pairs survive settings roundtrip");
+        for (const auto &pair : {std::pair{L"hello", L"привіт"}, {L"hello", L"hello"}, {L"hi!", L"hello"}})
+        {
+            auto invalid = settings;
+            invalid.autoReplacements = {{pair.first, pair.second}};
+            rejects([&] { ks::validateSettings(invalid); }, "invalid replacement pairs rejected");
+        }
         auto invalidWords = settings;
         invalidWords.autoWords[L"uk"] = {L"hello"};
         rejects([&] { ks::validateSettings(invalidWords); }, "personal dictionary rejects wrong language letters");

tools/build-dictionaries.py

@@ -4,7 +4,7 @@ import urllib.request, hashlib, json
 ROOT=Path(__file__).resolve().parents[1]/'dictionaries'
 REV='525f9b560de45753a5ea01069454e72e9aa541c6'
 # Supplemental vocabulary has no corpus frequency: rank after the 50k source list.
-SUPPLEMENTAL={'uk': {'реліз': 50001}}
+SUPPLEMENTAL={'uk': {'реліз': 50001, 'поточні': 50001}}
 ROOT.mkdir(exist_ok=True)
 manifest={}
 for lang in ('en','uk','ru'):