Release v0.6.21: skip unchanged layouts during conversion

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.24)
-project(KSwitcher VERSION 0.6.19 LANGUAGES CXX RC)
+project(KSwitcher VERSION 0.6.21 LANGUAGES CXX RC)
 if(NOT WIN32)
   message(FATAL_ERROR "KSwitcher uses native Windows APIs")
 endif()
@@ -17,6 +17,8 @@ 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(KSwitcherScrollTests tests/scroll.cpp)
+target_link_libraries(KSwitcherScrollTests PRIVATE kscore)
 target_link_libraries(KSwitcherTests PRIVATE kscore)
 add_executable(KSwitcherIntegration tests/integration.cpp src/screenshot_launcher.cpp src/screenshot_activation.cpp src/app.cpp src/screenshot_notifications.cpp src/screenshot.cpp src/configuration.cpp src/ui.cpp resources/app.rc)
 target_link_libraries(KSwitcherIntegration PRIVATE kscore)
@@ -39,7 +41,7 @@ endif()
 add_executable(KSwitcherOcrTests tests/ocr.cpp src/screenshot_launcher.cpp src/screenshot_activation.cpp src/app.cpp src/screenshot_notifications.cpp src/screenshot.cpp src/configuration.cpp src/ui.cpp resources/app.rc)
 target_link_libraries(KSwitcherOcrTests PRIVATE kscore)
 if(MSVC)
-  set_property(TARGET kscore KSwitcher KSwitcherConfig KSwitcherScreenshot KSwitcherTests KSwitcherIntegration KSwitcherInputTests KSwitcherOcrTests PROPERTY MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
+  set_property(TARGET kscore KSwitcher KSwitcherConfig KSwitcherScreenshot KSwitcherTests KSwitcherScrollTests KSwitcherIntegration KSwitcherInputTests KSwitcherOcrTests PROPERTY MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
   target_compile_options(kscore PRIVATE /W4 /utf-8)
   target_compile_options(KSwitcher PRIVATE /W4 /utf-8)
   target_compile_options(KSwitcherConfig PRIVATE /W4 /utf-8)
@@ -49,12 +51,14 @@ else()
   target_link_options(KSwitcherConfig PRIVATE -municode -static -static-libgcc -static-libstdc++)
   target_link_options(KSwitcherScreenshot PRIVATE -municode -static -static-libgcc -static-libstdc++)
   target_link_options(KSwitcherTests PRIVATE -static -static-libgcc -static-libstdc++)
+  target_link_options(KSwitcherScrollTests PRIVATE -static -static-libgcc -static-libstdc++)
   target_link_options(KSwitcherIntegration PRIVATE -static -static-libgcc -static-libstdc++)
   target_link_options(KSwitcherInputTests PRIVATE -static -static-libgcc -static-libstdc++)
   target_link_options(KSwitcherOcrTests PRIVATE -static -static-libgcc -static-libstdc++)
 endif()
 enable_testing()
 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 updater-regressions COMMAND powershell.exe -NoProfile -ExecutionPolicy Bypass -File "${CMAKE_CURRENT_SOURCE_DIR}/tests/update.ps1" -Executable "$<TARGET_FILE:KSwitcher>")

README.md

@@ -220,6 +220,8 @@ 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.
 - 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.
@@ -278,6 +280,12 @@ 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.
+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.
+
 Pressing the history shortcut a second time pastes the second-most-recent item.
 
 ## Data and migration

Release/README.md

@@ -1,21 +1,19 @@
 # Latest Windows release
 
-## v0.6.19 — 2026-10-31
+## v0.6.21 — 2026-10-31
 
 ## Changes
-- Retry a silently dropped Ctrl+C up to three total attempts, only while the transaction clipboard remains unchanged and the original input context is still valid. Failed snippet verification preserves the trigger and following input without sending Enter.
+- Next layout skips enabled layouts that leave the text unchanged and selects the next layout that changes it. Shared Russian/Ukrainian text such as `рф` and `шььш` becomes `ha` and `immi` when English follows in the cycle.
-- Exclude temporary transaction clipboard contents from Windows clipboard history and cloud synchronization. The original clipboard snapshot is still restored after the operation when ownership permits.
+- Configured order is preserved. If no enabled convertible layout changes the text, it remains unchanged and the operation advances one layout. Direct layout shortcuts retain their existing behavior.
-- Fix snippet integration test isolation: restore a multiline editor after earlier single-line scenarios, reset layout/correction state, coordinate test-editor clipboard access and disable unrelated background update checks.
-- Add deterministic coverage for one dropped copy and exhausted retries. Keep exact assertions for Enter ordering, buffered typing, clipboard restoration and subsequent auto-correction.
 
 ## Validation
-The fixes passed 230 native regression checks, 472 input/UI checks, screenshot editor UI and notification registration checks, 48 updater checks and updater progress checks. The full editor integration suite passed all 63 assertions; conversion-specific diagnostics also passed. The final snippet suite passed 20 consecutive runs, including injected copy failures and the three-attempt limit. The v0.6.19 staged Release build also passed the native, input/UI, screenshot and updater checks; the installed application was not replaced or restarted.
+Passed 413 native regressions, 473 input/UI checks, screenshot editor UI, notification registration, 48 updater checks and updater progress checks.
 
 ## Limitations
-The fix does not retry paste blindly: an editor may already have changed its selection or text. Clipboard contention, editor capabilities and input privileges can still prevent an operation. Existing accessibility readback limitations and problem-only diagnostic logging remain unchanged.
+Existing clipboard, accessibility and input-context verification limitations remain. Copy retries and paste readback verification are unchanged.
 
 **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 and extract the entire ZIP into its installation folder. Keep personal `data/` and customized dictionaries.
+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, Tesseract installation or language models.
 

Release/SHA256SUMS.txt

@@ -1 +1 @@
-8b2008e97ca625b7eebdf509c038d6d1f6c5c853dce6da1b939abaa18223e26d  KSwitcher-win-x64.zip
+5207831872af5522063c1c549ba582aaed534096e6e51a394b6be6a705951f3d  KSwitcher-win-x64.zip

build.ps1

@@ -10,6 +10,8 @@ $outDir = Join-Path $root 'build'
 New-Item -ItemType Directory -Force $outDir | Out-Null
 $executablePath = if ($Stage) { Join-Path $outDir 'staged\KSwitcher.exe' } else { Join-Path $outDir 'KSwitcher.exe' }
 New-Item -ItemType Directory -Force (Split-Path $executablePath) | Out-Null
+Set-Content -LiteralPath (Join-Path $outDir '.local-dev') -Value 'Local development build' -Encoding ascii
+Set-Content -LiteralPath (Join-Path (Split-Path $executablePath) '.local-dev') -Value 'Local development build' -Encoding ascii
 Push-Location $root
 try {
     $common = @('-std=c++20','-Os','-DNDEBUG','-DUNICODE','-D_UNICODE','-DWIN32_LEAN_AND_MEAN','-DNOMINMAX','-D_WIN32_WINNT=0x0A00','-Wall','-Wextra','-Wno-missing-field-initializers','-Isrc','-Ivendor','-ffunction-sections','-fdata-sections')
@@ -39,6 +41,10 @@ try {
     if ($LASTEXITCODE) { throw 'Screenshot link failed' }
     Copy-Item -LiteralPath $screenshotPath -Destination build/release/KSwitcher.Screenshot.exe -Force
     if ($Test) {
+        & $compiler @common tests/scroll.cpp @libs -static -s -o build/KSwitcherScrollTests.exe
+        if ($LASTEXITCODE) { throw 'Scroll test build failed' }
+        & .\build\KSwitcherScrollTests.exe
+        if ($LASTEXITCODE) { throw 'Scroll tests failed' }
         & $compiler @common tests/tests.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/ocr.o build/richtext.o build/update.o @libs -static -s -o build/KSwitcherTests.exe
         if ($LASTEXITCODE) { throw 'Test build failed' }
         & .\build\KSwitcherTests.exe

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 0,6,19,0
+ FILEVERSION 0,6,21,0
- PRODUCTVERSION 0,6,19,0
+ PRODUCTVERSION 0,6,21,0
  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", "0.6.19"
+   VALUE "FileVersion", "0.6.21"
   END
  END
  BLOCK "VarFileInfo"

src/app.cpp

@@ -433,7 +433,7 @@ void App::addTray()
     icon.uCallbackMessage = TrayMessage;
     icon.hIcon = (HICON)LoadImageW(instance, MAKEINTRESOURCEW(IDI_KSWITCHER), IMAGE_ICON,
                                    GetSystemMetrics(SM_CXSMICON), GetSystemMetrics(SM_CYSMICON), LR_SHARED);
-    wcscpy_s(icon.szTip, L"KSwitcher — keyboard layouts & clipboard");
+    wcscpy_s(icon.szTip, localBuildTitle(L"KSwitcher — keyboard layouts & clipboard").c_str());
     Shell_NotifyIconW(NIM_ADD, &icon);
     icon.uVersion = NOTIFYICON_VERSION_4;
     Shell_NotifyIconW(NIM_SETVERSION, &icon);
@@ -1202,11 +1202,7 @@ 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);
                     }

src/app.h

@@ -120,6 +120,7 @@ class App
 };
 void showHistory(App &, bool visible = true);
 void launchScreenshot(App &);
+void launchScreenshotEditor(App &, const Clip &);
 void refreshHistory(App &);
 void showSettings(App &, bool visible = true);
 void showLogs(App &);

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))

src/core.h

@@ -24,6 +24,8 @@ 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

src/history_preview.h

@@ -0,0 +1,17 @@
+#pragma once
+#include <map>
+#include <set>
+#include <string>
+
+namespace ks {
+// Keep the visible working set even in unusually tall windows. Never evict a
+// visible preview to admit another visible preview: that creates a paint loop.
+template<class T>
+void trimHistoryPreviews(std::map<std::wstring,T> &cache,
+                         const std::set<std::wstring> &visible, size_t limit=32)
+{
+    for(auto it=cache.begin(); cache.size()>limit && it!=cache.end();)
+        if(!visible.contains(it->first)) it=cache.erase(it);
+        else ++it;
+}
+}

src/platform.h

@@ -8,6 +8,16 @@
 
 namespace ks
 {
+inline std::wstring localBuildTitle(const std::wstring &title)
+{
+    static const bool development=[] {
+        wchar_t path[32768]{};
+        if(!GetModuleFileNameW(nullptr,path,std::size(path))) return false;
+        std::error_code error;
+        return std::filesystem::exists(std::filesystem::path(path).parent_path()/L".local-dev",error);
+    }();
+    return development?title+L" [LOCAL DEV]":title;
+}
 using Bytes = std::vector<unsigned char>;
 struct Format
 {

src/screenshot.cpp

@@ -841,7 +841,7 @@ void edit(HWND w, Capture &c)
     SetWindowLongPtrW(w,GWL_EXSTYLE,(GetWindowLongPtrW(w,GWL_EXSTYLE)|WS_EX_APPWINDOW)&~WS_EX_TOOLWINDOW);
     SetWindowLongPtrW(w,GWL_STYLE,WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN);
     auto title=L"KSwitcher — Screenshot #"+std::to_wstring(nextEditorIndex++);
-    SetWindowTextW(w,title.c_str());
+    SetWindowTextW(w,localBuildTitle(title).c_str());
     INITCOMMONCONTROLSEX statusControls{sizeof(statusControls),ICC_BAR_CLASSES};
     InitCommonControlsEx(&statusControls);
     CreateWindowExW(0,STATUSCLASSNAMEW,L"",WS_CHILD|WS_VISIBLE|SBARS_TOOLTIPS,

src/screenshot_launcher.cpp

@@ -1,13 +1,15 @@
 #include "app.h"
+#include "screenshot_notifications.h"
 
 namespace ks {
-void launchScreenshot(App &app)
+static void launch(App &app, const Clip *clip)
 {
     auto path=std::filesystem::path(executable()).parent_path()/L"KSwitcher.Screenshot.exe";
     if (!std::filesystem::exists(path))
         throw std::runtime_error("KSwitcher.Screenshot.exe is missing. Extract the complete application package.");
-    auto command=L"\""+path.wstring()+L"\" --auto-open-editor="+
+    auto command=L"\""+path.wstring()+L"\" ";
-        (app.settings.screenshotAutoOpenEditor?L"1":L"0");
+    if(clip) command+=L"--open kswitcher-screenshot:"+cacheScreenshotForEditor(*clip);
+    else command+=std::wstring(L"--auto-open-editor=")+(app.settings.screenshotAutoOpenEditor?L"1":L"0");
     if(app.settings.writeLog) command+=L" --write-log";
     STARTUPINFOW startup{sizeof(startup)};
     PROCESS_INFORMATION process{};
@@ -20,4 +22,6 @@ void launchScreenshot(App &app)
     CloseHandle(process.hThread);
     CloseHandle(process.hProcess);
 }
+void launchScreenshot(App &app) { launch(app,nullptr); }
+void launchScreenshotEditor(App &app,const Clip &clip) { launch(app,&clip); }
 }

src/screenshot_notifications.cpp

@@ -112,6 +112,19 @@ std::wstring escapeXml(const std::wstring &s)
     return result;
 }
 }
+std::wstring cacheScreenshotForEditor(const Clip &clip)
+{
+    // Normalize PNG/DIBV5 and other supported clipboard images at full resolution.
+    auto pixels=decodeImage(clip);
+    if(pixels.bgra.empty() || pixels.bgra.size()>128*1024*1024-sizeof(BITMAPINFOHEADER))
+        throw std::runtime_error("Image is too large for the screenshot editor");
+    auto dib=imageDib(pixels);
+    auto directory=cacheDirectory(); cleanCache(directory);
+    GUID guid{}; check(CoCreateGuid(&guid)); wchar_t value[40]{}; StringFromGUID2(guid,value,40);
+    std::wstring id(value+1,36);
+    atomicWrite(directory/(id+L".capture"),protect(dib.data));
+    return id;
+}
 Clip loadNotifiedScreenshot(const std::wstring &id)
 {
     if(!validScreenshotToken(id)) throw std::runtime_error("Invalid screenshot notification");

src/screenshot_notifications.h

@@ -8,4 +8,5 @@ int runScreenshotToastActivator();
 DWORD startScreenshotActivationListener();
 bool validScreenshotToken(const std::wstring &);
 Clip loadNotifiedScreenshot(const std::wstring &);
+std::wstring cacheScreenshotForEditor(const Clip &);
 }

src/ui.cpp

@@ -1,5 +1,7 @@
 #include "../resources/resource.h"
 #include "app.h"
+#include "history_preview.h"
+#include "ui_scroll.h"
 #include "configuration.h"
 #include "ocr.h"
 #include "richtext.h"
@@ -238,6 +240,9 @@ HWND control(HWND parent, const wchar_t *cls, const wchar_t *title, DWORD style,
                              scale(parent, width), scale(parent, height), parent, (HMENU)(INT_PTR)id,
                              GetModuleHandleW(nullptr), nullptr);
     SendMessageW(w, WM_SETFONT, (WPARAM)GetPropW(parent, L"Font"), TRUE);
+    if(wcscmp(cls,L"LISTBOX")==0 || wcscmp(cls,WC_LISTVIEWW)==0 ||
+       wcscmp(cls,L"COMBOBOX")==0 || (wcscmp(cls,L"EDIT")==0 && (style&ES_MULTILINE)))
+        enableWheelBatching(w,wcscmp(cls,L"LISTBOX")==0);
     if (auto *layout = windowLayoutState(parent); layout && layout->scrolling)
     {
         layout->controls.push_back({w, {x, y, x + width, y + height}});
@@ -368,11 +373,12 @@ HWND makeWindow(App &app, const wchar_t *cls, const wchar_t *title, WNDPROC proc
     int top = monitor.rcWork.top + std::max(0L, (monitor.rcWork.bottom - monitor.rcWork.top - outerHeight) / 2);
     SetPropW(w, L"WindowLayout", new WindowLayout{width, height, 0, 0, !(extra & WS_THICKFRAME)});
     SetWindowSubclass(w, layoutProc, 2, 0);
+    if(windowLayoutState(w)->scrolling) enableWheelBatching(w);
     RECT initial = fitWindowRect({left, top, left + outerWidth, top + outerHeight}, monitor.rcWork);
     SetWindowPos(w, nullptr, initial.left, initial.top, initial.right - initial.left, initial.bottom - initial.top,
                  SWP_NOACTIVATE | SWP_NOZORDER);
     arrangeWindow(w);
-    SetWindowTextW(w, title);
+    SetWindowTextW(w, localBuildTitle(title).c_str());
     auto smallIcon = (HICON)LoadImageW(app.instance, MAKEINTRESOURCEW(IDI_KSWITCHER), IMAGE_ICON,
                                        GetSystemMetricsForDpi(SM_CXSMICON, dpi),
                                        GetSystemMetricsForDpi(SM_CYSMICON, dpi), LR_SHARED);
@@ -478,7 +484,17 @@ struct HistoryView
     std::map<std::wstring, std::string> richTexts;
     HWND rich{};
     std::set<std::wstring> pending;
+    bool scrolling{};
 };
+bool selectedImage(HWND w, HistoryView *v)
+{
+    int i=(int)SendDlgItemMessageW(w,102,LB_GETCURSEL,0,0);
+    return i>=0 && i<(int)v->items.size() && v->items[i].image;
+}
+void updateHistoryActions(HWND w, HistoryView *v)
+{
+    SetDlgItemTextW(w,114,selectedImage(w,v)?L"Edit image":L"Open item");
+}
 std::wstring selected(HWND w, HistoryView *v)
 {
     int i = (int)SendDlgItemMessageW(w, 102, LB_GETCURSEL, 0, 0);
@@ -507,6 +523,7 @@ void search(HWND w, HistoryView *v)
 }
 void requestPreview(HWND w, HistoryView *v, const Entry &entry)
 {
+    if(v->scrolling) return;
     const auto id = entry.id;
     const bool image = entry.image;
     if (v->thumbnails.contains(id) || v->richTexts.contains(id) || !v->pending.insert(id).second)
@@ -690,6 +707,12 @@ LRESULT CALLBACK historyProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
     {
         switch (msg)
         {
+        case ScrollActivity:
+            if((HWND)wp==GetDlgItem(w,102)) {
+                v->scrolling=lp!=0;
+                if(!v->scrolling) InvalidateRect((HWND)wp,nullptr,FALSE);
+            }
+            return 0;
         case WM_COMMAND:
         {
             int id = LOWORD(wp);
@@ -702,6 +725,7 @@ LRESULT CALLBACK historyProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             }
             if (id == 102 && HIWORD(wp) == LBN_SELCHANGE)
             {
+                updateHistoryActions(w,v);
                 return 0;
             }
             if (id == 102 && HIWORD(wp) == LBN_DBLCLK)
@@ -747,10 +771,13 @@ LRESULT CALLBACK historyProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             if (result->generation != v->generation)
                 return 0;
             auto old = selected(w, v);
+            int top=(int)SendDlgItemMessageW(w,102,LB_GETTOPINDEX,0,0);
+            auto topId=top>=0 && top<(int)v->items.size()?v->items[top].id:L"";
             v->items = std::move(result->items);
             SendDlgItemMessageW(w, 102, WM_SETREDRAW, FALSE, 0);
             SendDlgItemMessageW(w, 102, LB_RESETCONTENT, 0, 0);
             int select = 0;
+            int restoreTop=0;
             for (size_t i = 0; i < v->items.size(); ++i)
             {
                 auto &e = v->items[i];
@@ -758,8 +785,11 @@ LRESULT CALLBACK historyProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 SendDlgItemMessageW(w, 102, LB_ADDSTRING, 0, (LPARAM)text.c_str());
                 if (e.id == old)
                     select = (int)i;
+                if(e.id==topId) restoreTop=(int)i;
             }
             SendDlgItemMessageW(w, 102, LB_SETCURSEL, select, 0);
+            SendDlgItemMessageW(w,102,LB_SETTOPINDEX,restoreTop,0);
+            updateHistoryActions(w,v);
             SendDlgItemMessageW(w, 102, WM_SETREDRAW, TRUE, 0);
             InvalidateRect(GetDlgItem(w, 102), nullptr, TRUE);
             return 0;
@@ -770,16 +800,25 @@ LRESULT CALLBACK historyProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             if (result->generation != v->generation || !IsWindowVisible(w))
                 return 0;
             v->pending.erase(result->id);
-            // At most ~3.3 MiB, irrespective of history length or source image size.
+            auto list=GetDlgItem(w,102);
-            if (v->thumbnails.size() >= 32)
+            RECT client{}; GetClientRect(list,&client);
-                v->thumbnails.erase(v->thumbnails.begin());
+            std::set<std::wstring> visible;
-            if (v->richTexts.size() >= 32)
+            RECT changed{}; bool repaint=false;
-                v->richTexts.erase(v->richTexts.begin());
+            int top=(int)SendMessageW(list,LB_GETTOPINDEX,0,0);
+            for(int i=std::max(0,top);i<(int)v->items.size();++i) {
+                RECT row{}, intersection{};
+                if(SendMessageW(list,LB_GETITEMRECT,i,(LPARAM)&row)==LB_ERR || row.top>=client.bottom) break;
+                if(!IntersectRect(&intersection,&row,&client)) continue;
+                visible.insert(v->items[i].id);
+                if(v->items[i].id==result->id) { changed=intersection; repaint=true; }
+            }
             if (!result->rtf.empty())
                 v->richTexts[result->id] = std::move(result->rtf);
             else
                 v->thumbnails[result->id] = std::move(result->pixels);
-            InvalidateRect(GetDlgItem(w, 102), nullptr, FALSE);
+            trimHistoryPreviews(v->thumbnails,visible);
+            trimHistoryPreviews(v->richTexts,visible);
+            if(repaint) InvalidateRect(list,&changed,FALSE);
             return 0;
         }
         case WM_MEASUREITEM:
@@ -798,15 +837,29 @@ LRESULT CALLBACK historyProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             break;
         case WM_CONTEXTMENU:
         {
+            auto list=GetDlgItem(w,102);
+            if((HWND)wp!=list) break;
+            POINT p{(short)LOWORD(lp),(short)HIWORD(lp)};
+            if(lp!=-1) {
+                POINT hit=p; ScreenToClient(list,&hit);
+                auto item=SendMessageW(list,LB_ITEMFROMPOINT,0,MAKELPARAM(hit.x,hit.y));
+                if(HIWORD(item)) return 0;
+                SendMessageW(list,LB_SETCURSEL,LOWORD(item),0);
+                updateHistoryActions(w,v);
+            } else {
+                RECT row{};
+                auto index=SendMessageW(list,LB_GETCURSEL,0,0);
+                if(index==LB_ERR) return 0;
+                SendMessageW(list,LB_GETITEMRECT,index,(LPARAM)&row);
+                p={row.left,row.top}; ClientToScreen(list,&p);
+            }
             HMENU menu = CreatePopupMenu();
             AppendMenuW(menu, MF_STRING, 110, L"Paste");
             AppendMenuW(menu, MF_STRING, 111, L"Paste plain text");
             AppendMenuW(menu, MF_STRING, 112, L"Pin / unpin");
             AppendMenuW(menu, MF_STRING, 113, L"Delete");
-            AppendMenuW(menu, MF_STRING, 114, 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)");
-            POINT p;
-            GetCursorPos(&p);
             int cmd = TrackPopupMenu(menu, TPM_RETURNCMD, p.x, p.y, 0, w, nullptr);
             DestroyMenu(menu);
             if (cmd)
@@ -1700,11 +1753,17 @@ void showEntry(App &app, const std::wstring &id)
     try
     {
         auto clip = app.history->load(id);
+        if(std::any_of(clip.formats.begin(),clip.formats.end(),[](const auto &format) {
+            return format.id==CF_DIB || format.id==CF_DIBV5 || format.name==L"PNG";
+        })) {
+            launchScreenshotEditor(app,clip);
+            return;
+        }
         auto text = clip.text();
         if (text.empty())
         {
             MessageBoxW(app.historyWindow,
-                        L"This item contains an image or files. Use the preview or paste it into the "
+                        L"This item contains files. Paste it into the "
                         L"destination application.",
                         L"Clipboard item", MB_OK);
             return;

src/ui_scroll.h

@@ -0,0 +1,83 @@
+#pragma once
+#include "platform.h"
+#include <algorithm>
+#include <commctrl.h>
+#include <windowsx.h>
+
+namespace ks {
+inline constexpr UINT ScrollActivity=WM_APP+42;
+inline constexpr UINT_PTR ScrollFrameTimer=0x4b5301, ScrollIdleTimer=0x4b5302;
+struct WheelBatch {
+    long long vertical{}, horizontal{};
+    WORD keys{};
+    LPARAM point{};
+    bool frame{}, active{}, listBox{};
+    int remainder{};
+};
+inline LRESULT CALLBACK wheelBatchProc(HWND w,UINT msg,WPARAM wp,LPARAM lp,UINT_PTR id,DWORD_PTR data)
+{
+    auto *batch=reinterpret_cast<WheelBatch *>(data);
+    if(msg==WM_MOUSEWHEEL || msg==WM_MOUSEHWHEEL) {
+        (msg==WM_MOUSEWHEEL?batch->vertical:batch->horizontal)+=GET_WHEEL_DELTA_WPARAM(wp);
+        batch->keys=GET_KEYSTATE_WPARAM(wp); batch->point=lp;
+        if(!batch->active) {
+            batch->active=true;
+            SendMessageW(GetParent(w),ScrollActivity,(WPARAM)w,TRUE);
+        }
+        // Do not restart the frame timer: an uninterrupted wheel stream must
+        // keep moving, rather than wait for a debounce interval to expire.
+        if(!batch->frame) batch->frame=SetTimer(w,ScrollFrameTimer,16,nullptr)!=0;
+        SetTimer(w,ScrollIdleTimer,100,nullptr);
+        return 0;
+    }
+    if(msg==WM_TIMER && wp==ScrollFrameTimer) {
+        KillTimer(w,ScrollFrameTimer); batch->frame=false;
+        if(batch->listBox && batch->vertical) {
+            UINT lines=3; SystemParametersInfoW(SPI_GETWHEELSCROLLLINES,0,&lines,0);
+            if(lines==WHEEL_PAGESCROLL) {
+                RECT client{}; GetClientRect(w,&client);
+                auto height=SendMessageW(w,LB_GETITEMHEIGHT,0,0);
+                lines=std::max<LRESULT>(1,client.bottom/std::max<LRESULT>(1,height));
+            }
+            auto delta=batch->vertical+batch->remainder;
+            batch->remainder=(int)(delta%WHEEL_DELTA);
+            auto top=SendMessageW(w,LB_GETTOPINDEX,0,0);
+            auto count=SendMessageW(w,LB_GETCOUNT,0,0);
+            auto next=std::clamp<long long>(top-(delta/WHEEL_DELTA)*lines,0,std::max<LRESULT>(0,count-1));
+            if(next!=top) SendMessageW(w,LB_SETTOPINDEX,(WPARAM)next,0);
+            batch->vertical=0;
+        } else if(batch->vertical) {
+            // Native edit/list-view/window handlers retain their own scrolling
+            // semantics, including system settings and partial wheel deltas.
+            auto delta=(short)std::clamp<long long>(batch->vertical,-32760,32760);
+            batch->vertical-=delta;
+            DefSubclassProc(w,WM_MOUSEWHEEL,MAKEWPARAM(batch->keys,(WORD)delta),batch->point);
+        }
+        if(batch->horizontal) {
+            auto delta=(short)std::clamp<long long>(batch->horizontal,-32760,32760);
+            batch->horizontal-=delta;
+            DefSubclassProc(w,WM_MOUSEHWHEEL,MAKEWPARAM(batch->keys,(WORD)delta),batch->point);
+        }
+        if(batch->vertical || batch->horizontal)
+            batch->frame=SetTimer(w,ScrollFrameTimer,16,nullptr)!=0;
+        return 0;
+    }
+    if(msg==WM_TIMER && wp==ScrollIdleTimer) {
+        if(batch->frame) return 0;
+        KillTimer(w,ScrollIdleTimer); batch->active=false;
+        SendMessageW(GetParent(w),ScrollActivity,(WPARAM)w,FALSE);
+        return 0;
+    }
+    if(msg==WM_NCDESTROY) {
+        KillTimer(w,ScrollFrameTimer); KillTimer(w,ScrollIdleTimer);
+        RemoveWindowSubclass(w,wheelBatchProc,id); delete batch;
+    }
+    return DefSubclassProc(w,msg,wp,lp);
+}
+inline void enableWheelBatching(HWND window,bool listBox=false)
+{
+    if(!window) return;
+    auto *batch=new WheelBatch; batch->listBox=listBox;
+    if(!SetWindowSubclass(window,wheelBatchProc,ScrollFrameTimer,(DWORD_PTR)batch)) delete batch;
+}
+}

src/update.h

@@ -2,7 +2,7 @@
 #include "platform.h"
 namespace ks
 {
-inline constexpr wchar_t AppVersion[] = L"0.6.19";
+inline constexpr wchar_t AppVersion[] = L"0.6.21";
 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

@@ -1,4 +1,5 @@
 #include "app.h"
+#include "ui_scroll.h"
 #include "ui_geometry.h"
 #include "screenshot.h"
 #include <commctrl.h>
@@ -728,16 +729,21 @@ int main(int argc, char **argv) {
             controlMoves=0;
             ValidateRect(settings,nullptr);
             SendMessageW(settings,WM_MOUSEWHEEL,MAKEWPARAM(0,WHEEL_DELTA),0);
+            SendMessageW(settings,WM_TIMER,ks::ScrollFrameTimer,0);
             require(controlMoves==0 && !GetUpdateRect(settings,nullptr,FALSE),"wheel at top does not move controls or erase the window");
             SendMessageW(settings,WM_MOUSEWHEEL,MAKEWPARAM(0,WORD(short(-WHEEL_DELTA/2))),0);
+            SendMessageW(settings,WM_TIMER,ks::ScrollFrameTimer,0);
             require(controlMoves==0,"partial wheel step does not rearrange controls");
             SendMessageW(settings,WM_MOUSEWHEEL,MAKEWPARAM(0,WORD(short(-WHEEL_DELTA/2))),0);
+            require(controlMoves==0,"wheel changes wait for the shared frame timer");
+            SendMessageW(settings,WM_TIMER,ks::ScrollFrameTimer,0);
             require(controlMoves==1,"wheel scroll batches each control movement once");
             SendMessageW(settings,WM_VSCROLL,SB_BOTTOM,0);
             SendMessageW(settings,WM_HSCROLL,SB_RIGHT,0);
             controlMoves=0;
             SendMessageW(settings,WM_MOUSEWHEEL,MAKEWPARAM(0,-WHEEL_DELTA),0);
             SendMessageW(settings,WM_MOUSEHWHEEL,MAKEWPARAM(0,WHEEL_DELTA),0);
+            SendMessageW(settings,WM_TIMER,ks::ScrollFrameTimer,0);
             require(controlMoves==0,"wheel at bottom and right boundaries does not rearrange controls");
             require((GetWindowLongPtrW(settings,GWL_STYLE)&WS_CLIPCHILDREN)!=0,"parent background excludes child controls");
             RemoveWindowSubclass(trackedControl,countControlMoves,99);

tests/screenshot_ui.cpp

@@ -175,7 +175,7 @@ int main()
         }
         c.marks.clear(); SendMessageW(window,WM_COMMAND,27,0);
         wchar_t windowTitle[128]{}; GetWindowTextW(window,windowTitle,128);
-        require(std::wstring(windowTitle)==L"KSwitcher — Screenshot #1","title includes editor index without usage hints");
+        require(std::wstring(windowTitle)==ks::localBuildTitle(L"KSwitcher — Screenshot #1"),"title includes editor index and local build marker without usage hints");
         RECT client{}; GetClientRect(window,&client);
         require(c.view.bottom<=client.bottom-c.statusHeight,"image does not overlap status bar");
         ks::updateStatus(c);

tests/scroll.cpp

@@ -0,0 +1,66 @@
+#include "ui_scroll.h"
+#include <iostream>
+
+namespace {
+int forwarded{};
+long long totalDelta{};
+LRESULT CALLBACK observe(HWND w,UINT msg,WPARAM wp,LPARAM lp,UINT_PTR,DWORD_PTR)
+{
+    if(msg==WM_MOUSEWHEEL) { ++forwarded; totalDelta+=GET_WHEEL_DELTA_WPARAM(wp); }
+    return DefSubclassProc(w,msg,wp,lp);
+}
+void require(bool ok,const char *message) { if(!ok) throw std::runtime_error(message); }
+void wheel(HWND w,int delta) { SendMessageW(w,WM_MOUSEWHEEL,MAKEWPARAM(0,(WORD)(short)delta),0); }
+void flush(HWND w) { SendMessageW(w,WM_TIMER,ks::ScrollFrameTimer,0); }
+}
+int main()
+{
+    INITCOMMONCONTROLSEX init{sizeof(init),ICC_STANDARD_CLASSES|ICC_LISTVIEW_CLASSES};
+    InitCommonControlsEx(&init);
+    auto instance=GetModuleHandleW(nullptr);
+    auto parent=CreateWindowW(L"STATIC",L"Scroll regression",WS_OVERLAPPEDWINDOW,0,0,500,400,nullptr,nullptr,instance,nullptr);
+    try {
+        auto list=CreateWindowW(L"LISTBOX",L"",WS_CHILD|WS_VSCROLL,0,0,300,200,parent,nullptr,instance,nullptr);
+        for(int i=0;i<2000;++i) SendMessageW(list,LB_ADDSTRING,0,(LPARAM)L"row");
+        SendMessageW(list,LB_SETCURSEL,5,0);
+        SendMessageW(list,LB_SETTOPINDEX,0,0);
+        ks::enableWheelBatching(list,true);
+        for(int i=0;i<1000;++i) wheel(list,-120);
+        require(SendMessageW(list,LB_GETTOPINDEX,0,0)==0,"burst is deferred to one frame");
+        flush(list);
+        UINT lines{}; SystemParametersInfoW(SPI_GETWHEELSCROLLLINES,0,&lines,0);
+        require(!lines || SendMessageW(list,LB_GETTOPINDEX,0,0)>0,"burst moves list");
+        require(SendMessageW(list,LB_GETCURSEL,0,0)==5,"scroll does not change selection");
+        for(int i=0;i<1000;++i) wheel(list,120);
+        flush(list);
+        require(SendMessageW(list,LB_GETTOPINDEX,0,0)==0,"reverse burst clamps at top");
+        wheel(list,-60); flush(list);
+        require(SendMessageW(list,LB_GETTOPINDEX,0,0)==0,"partial wheel step is retained");
+        wheel(list,-60); flush(list);
+        require(!lines || SendMessageW(list,LB_GETTOPINDEX,0,0)>0,"partial steps combine across frames");
+        DestroyWindow(list);
+        for(auto cls:{L"EDIT",WC_LISTVIEWW,L"COMBOBOX",L"STATIC"}) {
+            auto w=CreateWindowW(cls,L"",WS_CHILD|WS_VSCROLL,0,0,300,200,parent,nullptr,instance,nullptr);
+            require(w!=nullptr,"native scroll control created");
+            SetWindowSubclass(w,observe,1,0); ks::enableWheelBatching(w);
+            forwarded=0; totalDelta=0;
+            for(int i=0;i<100;++i) wheel(w,-120);
+            require(forwarded==0,"native wheel burst is batched");
+            flush(w);
+            require(forwarded==1 && totalDelta==-12000,"one native dispatch preserves burst distance");
+            wheel(w,60); flush(w);
+            require(forwarded==2 && totalDelta==-11940,"native partial steps are preserved");
+            forwarded=0; totalDelta=0;
+            for(int i=0;i<400;++i) wheel(w,-120);
+            flush(w); flush(w);
+            require(forwarded==2 && totalDelta==-48000,"large native burst is not truncated to 16 bits");
+            SendMessageW(w,WM_TIMER,ks::ScrollIdleTimer,0);
+            DestroyWindow(w);
+        }
+        DestroyWindow(parent);
+        std::cout<<"Passed shared wheel batching regressions (list, edit, table, combo, window)\n";
+        return 0;
+    } catch(const std::exception &e) {
+        DestroyWindow(parent); std::cerr<<e.what()<<'\n'; return 1;
+    }
+}

tests/tests.cpp

@@ -1,4 +1,5 @@
 #include "autocorrect.h"
+#include "history_preview.h"
 #include "ocr.h"
 #include "richtext.h"
 #include "storage.h"
@@ -22,6 +23,20 @@ void rejects(const std::function<void()> &f, const char *name)
     bool thrown = false;
     try
     {
+        {
+            std::map<std::wstring,int> previews;
+            std::set<std::wstring> visible;
+            for(int i=0;i<40;++i) previews[std::to_wstring(i)]=i;
+            for(int i=0;i<8;++i) visible.insert(std::to_wstring(i));
+            ks::trimHistoryPreviews(previews,visible);
+            require(previews.size()==32,"preview cache stays bounded");
+            for(const auto &id:visible) require(previews.contains(id),"visible preview survives eviction");
+            for(int i=0;i<40;++i) { auto id=std::to_wstring(i); previews[id]=i; visible.insert(id); }
+            ks::trimHistoryPreviews(previews,visible);
+            require(previews.size()==40,"tall viewport does not thrash visible previews");
+            visible.clear(); ks::trimHistoryPreviews(previews,visible);
+            require(previews.size()==32,"cache shrinks after leaving tall viewport");
+        }
         f();
     }
     catch (...)
@@ -322,6 +337,22 @@ 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");