KSwitcher

Native C++20 / Win32 rewrite of the Windows functionality of Typlo. Windows 10/11 x64. No .NET, Avalonia, WebView, Qt, external graphics engine, or separately installed C++ runtime. The original Typlo project and its data remain separate.

Run

Run build/KSwitcher.exe, or extract dist/KSwitcher-win-x64.zip and run the executable. 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. In Settings, enable Start with Windows and Start with Windows as administrator to use a per-user Task Scheduler logon task with highest privileges. Enabling or changing the elevated task requests UAC approval if the app is not already elevated. No password is stored; the task runs in the signed-in user's interactive session, including on battery power. Disabling the administrator option restores ordinary per-user startup; disabling startup stops future automatic launches. Saving unrelated settings does not recreate startup entries. KSwitcher.exe --settings opens Settings, including when the app is already running. Exit Typlo when using overlapping shortcuts to avoid competing keyboard hooks.

Change a shortcut

1. Open Settings and click a shortcut field.
2. Press the desired combination. The field records the actual keys; no typing of names is needed.
3. Click Save. Duplicate shortcuts within KSwitcher and protected Windows combinations are reported.

This also works for each layout's Direct layout shortcut. Backspace or Delete without modifiers clears a shortcut. Tab moves to the next field. The recorded shortcut is suppressed while the field has focus, so recording the conversion shortcut does not perform a conversion. All configured shortcuts use the existing keyboard hook and can replace ordinary Windows/app shortcuts, including Win+V and Win+Shift+S, while KSwitcher is running. Only exact configured combinations are intercepted. Unassigned shortcuts and simulated copy/paste pass through. Choose another shortcut or exit KSwitcher to restore the original action. Windows protects Ctrl+Alt+Delete and Win+L; these cannot be assigned.

Implemented

• Installed Windows keyboard layouts, configurable cycle/order and direct shortcuts; IMEs are switch-only.
• 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. If the editor's word boundary differs from the recorded typing, it falls back to paced character selection: Teams can coalesce a burst of Shift+Left events into just one character.
• Clipboard snapshot/restoration with concurrent-copy, foreground and input-version checks.
• Case cycling, Russian/Ukrainian transliteration, verified undo and repeated conversion.
• Text snippets across layouts, multiline insertion and a verified {cursor} position; {{cursor}} inserts the literal marker. Snippets are stored as plaintext settings, as in Typlo.
• Clipboard history for text, HTML/RTF, file lists, DIB and PNG images; plain-text paste; full-text search, pinning, deletion, full text viewing and image previews.
• Image thumbnails and text/file icons appear directly in the history list. Only visible rows load thumbnails; the 32-entry thumbnail cache is bounded to about 3.3 MiB and released on close.
• Text rows render RTF and basic clipboard HTML emphasis (bold, italic, underline, strike-through), paragraphs, line breaks and list bullets using native Windows RichEdit. Previews are bounded to 4096 characters / 64 KiB RTF, with at most 32 cached text previews; original paste formats are unchanged. HTML is parsed as text, without a browser, scripts or external resources. Complex web layouts and stylesheet rules are not reproduced; preview text uses the list's colors for readability.
• Consecutive screenshot copies are compared by image content, ignoring changing OLE transport metadata (including Snipping Tool's repeated clipboard publication).
• Windows OCR, entirely native and offline. Right-click an image in history and select Copy text from image. Requires a Windows OCR language installed for the user profile.
• History exclusion flags and excluded processes, pause/resume, count/size limits.
• Per-user Windows DPAPI encryption for both history payloads and the preview index.
• Autostart, keep-screen-awake, idle-only F15 activity signal, settings import/export.
• Single instance and --history, --convert, --case, --transliterate, --settings, --snippets, --exit commands. --convert cycles layouts.

Default shortcuts match Typlo: Ctrl+Alt+Shift+Space (cycle), C (case), T (transliteration), Z (undo), 1/2/3 (first layouts), and Ctrl+Shift+V (history).

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. Pressing the history shortcut a second time pastes the second-most-recent item.

Data and migration

Data is in data/ beside the executable, falling back to %LOCALAPPDATA%/KSwitcher when the executable's directory is not writable. Each clipboard payload is an encrypted disk file; only bounded previews/metadata stay in memory. Image data is loaded on demand and released when the history popup is hidden. The log contains operational messages, never copied text or keystrokes.

Settings Import accepts a Typlo settings.json, preserving supported Windows layout IDs, hotkeys, snippets, exclusions and limits. Import is staged until Save. Existing Typlo files are never modified. Typlo's encrypted SQLite history is not migrated to the new DPAPI file format. DPAPI data belongs to the Windows account/machine; copying the portable folder is not a cross-account backup.

Differences still to port

This is a working native implementation, not a claim of complete UI/release parity:

• UI currently uses English and the native Windows control appearance. Typlo's ten-language UI and explicit light/dark theme selector are not yet ported.
• Automatic release download/replacement is not enabled. KSwitcher has no configured release feed; using Typlo's feed would install the wrong application. Updates are manual.
• No import of old encrypted clipboard history. Export/import applies to settings.
• The clipboard popup is fixed-size with per-monitor DPI scaling; PNG/DIB previews use Windows WIC/GDI.

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.

Build

The easiest reproducible local route uses the pinned portable w64devkit toolchain:

.\setup-toolchain.ps1
.\build.ps1 -Test
.\package.ps1

setup-toolchain.ps1 downloads the compiler from its upstream GitHub release and verifies SHA-256. .tools/, build objects, test executables and compiler headers are development-only. Do not distribute the entire source/build folder. The package contains just the application and notices/documentation. The vendored JSON header is nlohmann/json 3.12.0 (MIT); it is compiled into the executable.

Alternatively open this directory as a CMake project in Visual Studio with the C++ desktop workload 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)

Enable Automatically correct layout (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.

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 trailing punctuation, including colon and semicolon. Empty fields disable stripping on that side. Up to three leading and six trailing characters (including the final space) are supported. Recognition still requires a verified complete word; punctuation inside a word is not stripped. Correction runs after Space, not immediately after a punctuation key. Save Settings to apply changes.

Frequency rank limit defaults to 0 (entire dictionary). A positive value allows corrections only to words with a rank at or below that number (for example, 10000). All dictionary words still protect already valid input, and ambiguous alternatives remain unchanged regardless of this limit. Open dictionary folder opens the files beside the running executable. After editing, click OK in the options window and Save in Settings to validate and reload the dictionaries without restarting. Use UTF-8, one lowercase word followed by a Tab and a positive rank per line; keep words sorted and unique. For a personal addition, rank 1 makes it eligible at every positive limit. Back up your edited files before replacing dictionaries with a new distribution.

After Space and a 250 ms typing pause, KSwitcher checks the last physically typed word against local dictionaries. For example, ghbdsn can become привіт . Continuing to type cancels pending work. It only corrects unknown words when exactly one alternative is a dictionary word. Minimum word length defaults to 3 and can be set from 1 to 32 letters. Surrounding punctuation does not count toward this minimum; the maximum word length is 32 letters. Known words, ambiguous alternatives, ALL CAPS, mixed-case identifiers, numbers, URLs and email addresses are left unchanged. Short trailing punctuation is retained when the editor selects it together with the word. Actual selected text is verified before replacement. Layout switching follows the existing switch-layout setting. The configured Undo shortcut restores the original and suppresses that word for the rest of the session (until restart).

Password fields and inaccessible controls are skipped using Windows UI Automation. Editors, terminals and password managers are excluded by default; process names can be edited in the options window. Controls that do not expose an editable/document element or cannot select a complete word may not support automatic correction. Dictionary recognition is heuristic, not an understanding of the sentence; subtitle vocabulary is incomplete, and uncommon names or jargon can need personal exceptions.

No network service or language model is used. The three dictionary files occupy about 2.6 MB on disk; the English/Ukrainian lookup data uses less than 3 MiB of RAM and is loaded on first automatic check. Keep dictionaries/ beside the executable when copying the app. These word lists derive from FrequencyWords and are separately licensed under CC BY-SA 4.0; attribution, pinned source revision and license are in dictionaries/.

Latest compiled release

The Release folder contains the latest portable Windows x64 ZIP and SHA-256 checksum. Run ./package.ps1 -PublishRelease after building and testing to refresh the tracked release archive.

Verification

.\build.ps1 -Test          # Pure/native regression checks; does not touch the user's clipboard
.\build.ps1 -Ocr           # Render a synthetic image, decode it with WIC and recognize it with Windows OCR
.\build.ps1 -Integration   # Interactive, isolated test editor; avoid input for about 10 seconds

The interactive test requires installed English-US and Russian layouts. It opens its own editor, tests real copy/paste, undo, repeat conversion, recent-input verification and snippet cursor placement, then restores the clipboard. Test data is stored in its own temporary directory. It never sends messages to Teams or other user applications. Do not run it while typing elsewhere.

KSwitcher.exe --smoke-test starts a normal tray instance and exits after ten seconds for idle-memory checks. It still uses the normal instance lock; close a running KSwitcher first if measuring a fresh process.

Structure

• core.*: conversion, transliteration, snippets, shortcut parsing/formatting, recent-input model.
• platform.*: Win32 layouts, clipboard, input, ownership, DPAPI and file primitives.
• storage.*: settings and encrypted, disk-backed history.
• app.*: message loop, hooks, background work and guarded text transactions.
• ui.cpp: native windows and shortcut recording.
• ocr.*: Windows WIC and OCR via the native Windows Runtime ABI.
• tests/: regression checks, real editor integration and OCR fixture.

Application code is MIT licensed; preserves the original Typlo attribution in LICENSE. Dictionary data has its own CC BY-SA 4.0 license as described above.