Pick an application by dragging onto its highlighted window

README.md

@@ -913,6 +913,8 @@ choices and become independent profiles when this dialog is applied.
 The list includes running applications and saved profiles. Add a closed application
 by its executable name, such as `Codex.exe`. Matching ignores case and `.exe` and
 covers all windows of that executable, including all tabs of a browser.
+To identify an open application, drag **Drag to window** onto its window. An outline
+shows which window will be selected. Release to select its executable or press **Esc** to cancel.
 Applications without a custom profile use the default languages; merely viewing
 an application does not create a profile. **Use defaults** clears only the selected
 application's custom choice. Switching applications preserves pending edits.
@@ -937,6 +939,9 @@ settings export/import.
 цього вікна. У списку є відкриті програми та збережені профілі; закриту програму
 можна додати за назвою файла, наприклад `Codex.exe`. Регістр і `.exe` не мають
 значення. Правило охоплює всі вікна програми, зокрема всі вкладки браузера.
+Щоб визначити відкриту програму, перетягни приціл **Drag to window** на її вікно.
+Рамка показує, яке вікно буде вибрано. Відпусти приціл, щоб вибрати програму,
+або натисни **Esc**, щоб скасувати.
 Без окремого профілю діють загальні мови; простий перегляд програми не створює
 профіль. **Use defaults** повертає лише вибрану програму до загальних мов.
 Перехід між програмами зберігає чернетки. **Use languages**, потім **Save**

src/ui_app_languages.inl

@@ -12,7 +12,18 @@ struct AppLanguagesView
     std::vector<std::wstring> applications;
     int selection = -1;
     bool dirty{};
+    HWND pickerOutline{};
 };
+constexpr UINT AppWindowPicked = WM_APP + 78;
+void showAppLanguageStatus(HWND w, const AppLanguagesView &v)
+{
+    if (v.selection < 0)
+        value(w, 721, L"Select an application, drag the crosshair, or enter an executable name.");
+    else if (v.dirty || v.profiles.contains(v.applications[v.selection]))
+        value(w, 721, L"Custom languages for this application. Other applications are unchanged.");
+    else
+        value(w, 721, L"Using default languages. Click languages to customize this application.");
+}
 void fillAppLanguages(HWND w, AppLanguagesView *v)
 {
     bool selected = v->selection >= 0 && v->selection < (int)v->applications.size();
@@ -21,7 +32,7 @@ void fillAppLanguages(HWND w, AppLanguagesView *v)
     if (!selected)
     {
         EnableWindow(GetDlgItem(w, 725), FALSE);
-        value(w, 721, L"Select an application, or add its executable name below.");
+        showAppLanguageStatus(w, *v);
         return;
     }
     auto found = v->profiles.find(v->applications[v->selection]);
@@ -32,8 +43,7 @@ void fillAppLanguages(HWND w, AppLanguagesView *v)
         SendDlgItemMessageW(w, 722, LB_SETSEL,
             std::find(cycle.begin(), cycle.end(), id) != cycle.end(), i);
     }
-    value(w, 721, found == v->profiles.end() ? L"Using default languages. Click languages to customize this application." :
-        L"Custom languages for this application. Other applications are unchanged.");
+    showAppLanguageStatus(w, *v);
     EnableWindow(GetDlgItem(w, 725), found != v->profiles.end());
 }
 void collectAppLanguages(HWND w, AppLanguagesView *v)
@@ -47,12 +57,141 @@ void collectAppLanguages(HWND w, AppLanguagesView *v)
     v->profiles[v->applications[v->selection]] = std::move(cycle);
     v->dirty = false;
 }
+void selectAppLanguageProfile(HWND w, AppLanguagesView *v, const std::wstring &app)
+{
+    collectAppLanguages(w, v);
+    auto found = std::find(v->applications.begin(), v->applications.end(), app);
+    int index = (int)(found - v->applications.begin());
+    if (found == v->applications.end())
+    {
+        auto row = SendDlgItemMessageW(w, 720, LB_ADDSTRING, 0, (LPARAM)app.c_str());
+        if (row < 0) throw std::runtime_error("Could not add the application to the list.");
+        v->applications.push_back(app);
+    }
+    v->selection = index;
+    SendDlgItemMessageW(w, 720, LB_SETCURSEL, index, 0);
+    fillAppLanguages(w, v);
+}
+HWND appPickerTarget(HWND button, LPARAM position)
+{
+    POINT point{(short)LOWORD(position), (short)HIWORD(position)};
+    ClientToScreen(button, &point);
+    auto target = GetAncestor(WindowFromPoint(point), GA_ROOT);
+    auto dialog = GetParent(button);
+    return target && target != dialog && target != GetWindow(dialog, GW_OWNER) ? target : nullptr;
+}
+void updatePickerOutline(HWND dialog, AppLanguagesView &v, HWND target)
+{
+    RECT bounds{};
+    if (!target || !GetWindowRect(target, &bounds) || IsRectEmpty(&bounds))
+    {
+        if (v.pickerOutline) ShowWindow(v.pickerOutline, SW_HIDE);
+        return;
+    }
+    if (!v.pickerOutline)
+    {
+        WNDCLASSW windowClass{};
+        windowClass.lpfnWndProc = DefWindowProcW;
+        windowClass.hInstance = GetModuleHandleW(nullptr);
+        windowClass.hbrBackground = GetSysColorBrush(COLOR_HIGHLIGHT);
+        windowClass.lpszClassName = L"KSwitcher.AppPickerOutline";
+        RegisterClassW(&windowClass);
+        v.pickerOutline = CreateWindowExW(WS_EX_LAYERED | WS_EX_TRANSPARENT | WS_EX_TOOLWINDOW | WS_EX_NOACTIVATE,
+            windowClass.lpszClassName, nullptr, WS_POPUP, 0, 0, 0, 0, dialog, nullptr, windowClass.hInstance, nullptr);
+        if (!v.pickerOutline) return;
+        if (!SetLayeredWindowAttributes(v.pickerOutline, 0, 255, LWA_ALPHA))
+        {
+            DestroyWindow(v.pickerOutline);
+            v.pickerOutline = nullptr;
+            return;
+        }
+    }
+    RECT previous{};
+    if (IsWindowVisible(v.pickerOutline) && GetWindowRect(v.pickerOutline, &previous) && EqualRect(&bounds, &previous)) return;
+    int width = bounds.right - bounds.left, height = bounds.bottom - bounds.top;
+    int stroke = scale(target, 4);
+    HRGN frame = CreateRectRgn(0, 0, width, height);
+    if (!frame) return;
+    if (width > 2 * stroke && height > 2 * stroke)
+    {
+        HRGN opening = CreateRectRgn(stroke, stroke, width - stroke, height - stroke);
+        if (opening)
+        {
+            CombineRgn(frame, frame, opening, RGN_DIFF);
+            DeleteObject(opening);
+        }
+    }
+    if (!SetWindowRgn(v.pickerOutline, frame, TRUE))
+    {
+        DeleteObject(frame);
+        return;
+    }
+    SetWindowPos(v.pickerOutline, HWND_TOPMOST, bounds.left, bounds.top, width, height, SWP_NOACTIVATE | SWP_SHOWWINDOW);
+}
+LRESULT CALLBACK appWindowPickerProc(HWND button, UINT msg, WPARAM wp, LPARAM lp, UINT_PTR id, DWORD_PTR)
+{
+    HWND dialog = GetParent(button);
+    auto *view = (AppLanguagesView *)GetWindowLongPtrW(dialog, GWLP_USERDATA);
+    if (msg == WM_LBUTTONDOWN)
+    {
+        SetFocus(button);
+        SetCapture(button);
+        if (GetCapture() == button)
+        {
+            SetCursor(LoadCursorW(nullptr, IDC_CROSS));
+            SetDlgItemTextW(dialog, 721, L"Drag to the application's window and release. Esc cancels.");
+        }
+        return 0;
+    }
+    if (msg == WM_CAPTURECHANGED || msg == WM_NCDESTROY)
+    {
+        if (view && view->pickerOutline)
+        {
+            DestroyWindow(view->pickerOutline);
+            view->pickerOutline = nullptr;
+        }
+        if (msg == WM_CAPTURECHANGED) SendMessageW(dialog, AppWindowPicked, 0, 0);
+    }
+    if (GetCapture() == button)
+    {
+        if (msg == WM_GETDLGCODE && wp == VK_ESCAPE) return DLGC_WANTMESSAGE;
+        if (msg == WM_CANCELMODE || msg == WM_RBUTTONDOWN || (msg == WM_KEYDOWN && wp == VK_ESCAPE))
+        {
+            ReleaseCapture();
+            return 0;
+        }
+        if (msg == WM_MOUSEMOVE || msg == WM_SETCURSOR)
+        {
+            SetCursor(LoadCursorW(nullptr, IDC_CROSS));
+            if (msg == WM_MOUSEMOVE && view) updatePickerOutline(dialog, *view, appPickerTarget(button, lp));
+            return TRUE;
+        }
+        if (msg == WM_LBUTTONUP)
+        {
+            HWND target = appPickerTarget(button, lp);
+            ReleaseCapture();
+            SendMessageW(dialog, AppWindowPicked, (WPARAM)target, 1);
+            return 0;
+        }
+    }
+    if (msg == WM_NCDESTROY) RemoveWindowSubclass(button, appWindowPickerProc, id);
+    return DefSubclassProc(button, msg, wp, lp);
+}
 LRESULT CALLBACK appLanguagesProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
 {
     auto *v = (AppLanguagesView *)GetWindowLongPtrW(w, GWLP_USERDATA);
     if (!v) return DefWindowProcW(w, msg, wp, lp);
     try
     {
+        if (msg == AppWindowPicked)
+        {
+            if (!lp) { showAppLanguageStatus(w, *v); return 0; }
+            HWND target = (HWND)wp;
+            auto app = target && target != w && target != v->parent ? applicationName(processName(target)) : L"";
+            if (app.empty()) value(w, 721, L"No application found. Release the crosshair over another window.");
+            else selectAppLanguageProfile(w, v, app);
+            return 0;
+        }
         if (msg == WM_COMMAND)
         {
             int id = LOWORD(wp);
@@ -60,7 +199,7 @@ LRESULT CALLBACK appLanguagesProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             {
                 v->dirty = true;
                 EnableWindow(GetDlgItem(w, 725), TRUE);
-                value(w, 721, L"Custom languages for this application. Other applications are unchanged.");
+                showAppLanguageStatus(w, *v);
                 return 0;
             }
             if (id == 720 && HIWORD(wp) == LBN_SELCHANGE)
@@ -85,17 +224,7 @@ LRESULT CALLBACK appLanguagesProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 Settings check;
                 check.appLanguageSets[L"check"] = {{L"win:04090409"}, {app}};
                 validateSettings(check);
-                collectAppLanguages(w, v);
-                auto found = std::find(v->applications.begin(), v->applications.end(), app);
-                int index = (int)(found - v->applications.begin());
-                if (found == v->applications.end())
-                {
-                    v->applications.push_back(app);
-                    SendDlgItemMessageW(w, 720, LB_ADDSTRING, 0, (LPARAM)app.c_str());
-                }
-                v->selection = index;
-                SendDlgItemMessageW(w, 720, LB_SETCURSEL, index, 0);
-                fillAppLanguages(w, v);
+                selectAppLanguageProfile(w, v, app);
                 value(w, 726, L"");
                 SetFocus(GetDlgItem(w, 722));
                 return 0;
@@ -148,7 +277,9 @@ void showAppLanguages(HWND parent, SettingsView *settings)
     v->applications.assign(apps.begin(), apps.end());
     SetWindowLongPtrW(w, GWLP_HWNDPARENT, (LONG_PTR)parent);
     SetWindowLongPtrW(w, GWLP_USERDATA, (LONG_PTR)v);
-    label(w, L"Application", 18, 16, 278);
+    label(w, L"Application", 18, 16, 108);
+    button(w, L"⊕ Drag to window", 728, 132, 10, 164);
+    SetWindowSubclass(GetDlgItem(w, 728), appWindowPickerProc, 1, 0);
     control(w, L"LISTBOX", L"", WS_TABSTOP | WS_VSCROLL | LBS_NOTIFY | LBS_NOINTEGRALHEIGHT | WS_BORDER,
             720, 18, 44, 278, 280);
     label(w, L"Allowed languages (click to include)", 316, 16, 386);

tests/chat_profiles.cpp

@@ -279,6 +279,35 @@ int main()
             require(SendDlgItemMessageW(dialog, 722, LB_GETSELCOUNT, 0, 0) == 1, "legacy languages displayed");
             SendDlgItemMessageW(dialog, 722, LB_SETSEL, TRUE, -1);
             SendMessageW(dialog, WM_COMMAND, MAKEWPARAM(722, LBN_SELCHANGE), 0);
+            HWND picker = GetDlgItem(dialog, 728);
+            RECT dialogBounds{};
+            GetWindowRect(dialog, &dialogBounds);
+            HWND target = CreateWindowExW(WS_EX_TOPMOST | WS_EX_NOACTIVATE, L"EDIT", L"Picker fixture",
+                WS_POPUP | WS_VISIBLE, dialogBounds.left + 32, dialogBounds.top + 100, 120, 48,
+                nullptr, nullptr, GetModuleHandleW(nullptr), nullptr);
+            require(picker && target, "window picker and target available");
+            POINT drop{dialogBounds.left + 33, dialogBounds.top + 101};
+            require(GetAncestor(WindowFromPoint(drop), GA_ROOT) == target, "fixture window is under the drop point");
+            ScreenToClient(picker, &drop);
+            SendMessageW(picker, WM_LBUTTONDOWN, MK_LBUTTON, MAKELPARAM(8, 8));
+            require(GetCapture() == picker, "window picker captures drag");
+            SendMessageW(picker, WM_MOUSEMOVE, MK_LBUTTON, MAKELPARAM(drop.x, drop.y));
+            HWND outline = findTestWindow(L"KSwitcher.AppPickerOutline", nullptr);
+            RECT outlineBounds{}, targetBounds{};
+            require(IsWindowVisible(outline) && GetWindowRect(outline, &outlineBounds) &&
+                GetWindowRect(target, &targetBounds) && EqualRect(&outlineBounds, &targetBounds), "drag highlights the target window");
+            SendMessageW(picker, WM_KEYDOWN, VK_ESCAPE, 0);
+            require(!IsWindow(outline) && GetCapture() != picker, "Escape clears the outline and releases capture");
+            SendMessageW(picker, WM_LBUTTONDOWN, MK_LBUTTON, MAKELPARAM(8, 8));
+            SendMessageW(picker, WM_MOUSEMOVE, MK_LBUTTON, MAKELPARAM(drop.x, drop.y));
+            outline = findTestWindow(L"KSwitcher.AppPickerOutline", nullptr);
+            SendMessageW(picker, WM_LBUTTONUP, 0, MAKELPARAM(drop.x, drop.y));
+            require(!IsWindow(outline), "dropping clears the outline");
+            auto pickedApp = ks::applicationName(ks::processName(target));
+            DestroyWindow(target);
+            auto pickedRow = SendDlgItemMessageW(dialog, 720, LB_FINDSTRINGEXACT, -1, (LPARAM)pickedApp.c_str());
+            require(GetCapture() != picker && pickedRow >= 0 &&
+                SendDlgItemMessageW(dialog, 720, LB_GETCURSEL, 0, 0) == pickedRow, "dropping on a window selects its executable");
             selectApp(L"notepad");
             require(SendDlgItemMessageW(dialog, 722, LB_GETSELCOUNT, 0, 0) == 1, "editing one app leaves formerly shared app unchanged");
             selectApp(L"codex");