Backends: Win32, SDL: maintain MouseButtonsDown instead of using IsAnyMouseDown(). Internals: added GetInputSourceName().

backends/imgui_impl_sdl.cpp

@@ -18,6 +18,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2022-01-12: Maintain our own copy of MouseButtonsDown mask instead of using ImGui::IsAnyMouseDown() which will be obsoleted.
 //  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModsEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2021-08-17: Calling io.AddFocusEvent() on SDL_WINDOWEVENT_FOCUS_GAINED/SDL_WINDOWEVENT_FOCUS_LOST.
 //  2021-07-29: Inputs: MousePos is correctly reported when the host platform window is hovered but not focused (using SDL_GetMouseFocus() + SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, requires SDL 2.0.5+)
@@ -74,6 +75,7 @@ struct ImGui_ImplSDL2_Data
 {
     SDL_Window* Window;
     Uint64      Time;
+    int         MouseButtonsDown;
     bool        MousePressed[3];
     SDL_Cursor* MouseCursors[ImGuiMouseCursor_COUNT];
     char*       ClipboardTextData;
@@ -240,10 +242,17 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
             return true;
         }
         case SDL_MOUSEBUTTONDOWN:
+        case SDL_MOUSEBUTTONUP:
         {
-            if (event->button.button == SDL_BUTTON_LEFT) { bd->MousePressed[0] = true; }
-            if (event->button.button == SDL_BUTTON_RIGHT) { bd->MousePressed[1] = true; }
-            if (event->button.button == SDL_BUTTON_MIDDLE) { bd->MousePressed[2] = true; }
+            int mouse_button = -1;
+            if (event->button.button == SDL_BUTTON_LEFT) { mouse_button = 0; }
+            if (event->button.button == SDL_BUTTON_RIGHT) { mouse_button = 1; }
+            if (event->button.button == SDL_BUTTON_MIDDLE) { mouse_button = 2; }
+            if (mouse_button == -1)
+                break;
+            if (event->type == SDL_MOUSEBUTTONDOWN)
+                bd->MousePressed[mouse_button] = true;
+            bd->MouseButtonsDown = (event->type == SDL_MOUSEBUTTONDOWN) ? (bd->MouseButtonsDown | (1 << mouse_button)) : (bd->MouseButtonsDown & ~(1 << mouse_button));
             return true;
         }
         case SDL_TEXTINPUT:
@@ -409,7 +418,7 @@ static void ImGui_ImplSDL2_UpdateMousePosAndButtons()
         mouse_window = focused_window;
 
     // SDL_CaptureMouse() let the OS know e.g. that our imgui drag outside the SDL window boundaries shouldn't e.g. trigger other operations outside
-    SDL_CaptureMouse(ImGui::IsAnyMouseDown() ? SDL_TRUE : SDL_FALSE);
+    SDL_CaptureMouse(bd->MouseButtonsDown != 0 ? SDL_TRUE : SDL_FALSE);
 #else
     // SDL 2.0.3 and non-windowed systems: single-viewport only
     SDL_Window* mouse_window = (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_INPUT_FOCUS) ? bd->Window : NULL;

backends/imgui_impl_win32.cpp

@@ -33,6 +33,7 @@ typedef DWORD (WINAPI *PFN_XInputGetState)(DWORD, XINPUT_STATE*);
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2022-01-12: Maintain our own copy of MouseButtonsDown mask instead of using ImGui::IsAnyMouseDown() which will be obsoleted.
 //  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModsEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2021-12-16: Inputs: Fill VK_LCONTROL/VK_RCONTROL/VK_LSHIFT/VK_RSHIFT/VK_LMENU/VK_RMENU for completeness.
 //  2021-08-17: Calling io.AddFocusEvent() on WM_SETFOCUS/WM_KILLFOCUS messages.
@@ -74,6 +75,7 @@ struct ImGui_ImplWin32_Data
     HWND                        hWnd;
     HWND                        MouseHwnd;
     bool                        MouseTracked;
+    int                         MouseButtonsDown;
     INT64                       Time;
     INT64                       TicksPerSecond;
     ImGuiMouseCursor            LastMouseCursor;
@@ -531,9 +533,10 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARA
         if (msg == WM_RBUTTONDOWN || msg == WM_RBUTTONDBLCLK) { button = 1; }
         if (msg == WM_MBUTTONDOWN || msg == WM_MBUTTONDBLCLK) { button = 2; }
         if (msg == WM_XBUTTONDOWN || msg == WM_XBUTTONDBLCLK) { button = (GET_XBUTTON_WPARAM(wParam) == XBUTTON1) ? 3 : 4; }
-        if (!ImGui::IsAnyMouseDown() && ::GetCapture() == NULL)
+        if (bd->MouseButtonsDown == 0 && ::GetCapture() == NULL)
             ::SetCapture(hwnd);
         io.MouseDown[button] = true;
+        bd->MouseButtonsDown |= 1 << button;
         return 0;
     }
     case WM_LBUTTONUP:
@@ -547,7 +550,8 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARA
         if (msg == WM_MBUTTONUP) { button = 2; }
         if (msg == WM_XBUTTONUP) { button = (GET_XBUTTON_WPARAM(wParam) == XBUTTON1) ? 3 : 4; }
         io.MouseDown[button] = false;
-        if (!ImGui::IsAnyMouseDown() && ::GetCapture() == hwnd)
+        bd->MouseButtonsDown &= ~(1 << button);
+        if (bd->MouseButtonsDown == 0 && ::GetCapture() == hwnd)
             ::ReleaseCapture();
         return 0;
     }

docs/CHANGELOG.txt

@@ -97,6 +97,7 @@ Other Changes:
   We are now converting GLFW untranslated keycodes back to translated keycodes in order to match the behavior of every
   other backend, and facilitate the use of GLFW with lettered-shortcuts API. (#456, #2625)
 - Backends: SDL: Pass localized keys (matching keyboard layout). Fix e.g. CTRL+A, CTRL+Z, CTRL+Y shortcuts.
+- Backends: Win32, SDL: Maintain a MouseButtonsDown mask instead of using ImGui::IsAnyMouseDown() which will be obsoleted.
 - Backends: Allegro5, GLFW, GLUT, SDL, OSX, Win32, Android: Updated to use io.AddKeyEvent() with full key range. (#2625) [@thedmd]
 - Backends: OpenGL3: Fixed a buffer overflow in imgui_impl_opengl3_loader.h init (added in 1.86). (#4468, #4830) [@dymk]
   It would generally not have noticeable side-effect at runtime but would be detected by runtime checkers.

imgui.cpp

@@ -7585,6 +7585,7 @@ bool ImGui::IsMousePosValid(const ImVec2* mouse_pos)
     return p.x >= MOUSE_INVALID && p.y >= MOUSE_INVALID;
 }
 
+// [WILL OBSOLETE] This was designed for backends, but prefer having backend maintain a mask of held mouse buttons, because upcoming input queue system will make this invalid.
 bool ImGui::IsAnyMouseDown()
 {
     ImGuiContext& g = *GImGui;
@@ -7642,6 +7643,13 @@ void ImGui::CaptureMouseFromApp(bool capture)
     g.WantCaptureMouseNextFrame = capture ? 1 : 0;
 }
 
+static const char* GetInputSourceName(ImGuiInputSource source)
+{
+    const char* input_source_names[] = { "None", "Mouse", "Keyboard", "Gamepad", "Nav", "Clipboard" };
+    IM_ASSERT(IM_ARRAYSIZE(input_source_names) == ImGuiInputSource_COUNT && source >= 0 && source < ImGuiInputSource_COUNT);
+    return input_source_names[source];
+}
+
 
 //-----------------------------------------------------------------------------
 // [SECTION] ERROR CHECKING
@@ -12107,8 +12115,6 @@ void ImGui::ShowMetricsWindow(bool* p_open)
     // Misc Details
     if (TreeNode("Internal state"))
     {
-        const char* input_source_names[] = { "None", "Mouse", "Keyboard", "Gamepad", "Nav", "Clipboard" }; IM_ASSERT(IM_ARRAYSIZE(input_source_names) == ImGuiInputSource_COUNT);
-
         Text("WINDOWING");
         Indent();
         Text("HoveredWindow: '%s'", g.HoveredWindow ? g.HoveredWindow->Name : "NULL");
@@ -12119,7 +12125,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
 
         Text("ITEMS");
         Indent();
-        Text("ActiveId: 0x%08X/0x%08X (%.2f sec), AllowOverlap: %d, Source: %s", g.ActiveId, g.ActiveIdPreviousFrame, g.ActiveIdTimer, g.ActiveIdAllowOverlap, input_source_names[g.ActiveIdSource]);
+        Text("ActiveId: 0x%08X/0x%08X (%.2f sec), AllowOverlap: %d, Source: %s", g.ActiveId, g.ActiveIdPreviousFrame, g.ActiveIdTimer, g.ActiveIdAllowOverlap, GetInputSourceName(g.ActiveIdSource));
         Text("ActiveIdWindow: '%s'", g.ActiveIdWindow ? g.ActiveIdWindow->Name : "NULL");
 
         int active_id_using_key_input_count = 0;
@@ -12134,7 +12140,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
         Indent();
         Text("NavWindow: '%s'", g.NavWindow ? g.NavWindow->Name : "NULL");
         Text("NavId: 0x%08X, NavLayer: %d", g.NavId, g.NavLayer);
-        Text("NavInputSource: %s", input_source_names[g.NavInputSource]);
+        Text("NavInputSource: %s", GetInputSourceName(g.NavInputSource));
         Text("NavActive: %d, NavVisible: %d", g.IO.NavActive, g.IO.NavVisible);
         Text("NavActivateId/DownId/PressedId/InputId: %08X/%08X/%08X/%08X", g.NavActivateId, g.NavActivateDownId, g.NavActivatePressedId, g.NavActivateInputId);
         Text("NavActivateFlags: %04X", g.NavActivateFlags);

imgui.h

@@ -908,7 +908,7 @@ namespace ImGui
     IMGUI_API int           GetMouseClickedCount(ImGuiMouseButton button);                      // return the number of successive mouse-clicks at the time where a click happen (otherwise 0).
     IMGUI_API bool          IsMouseHoveringRect(const ImVec2& r_min, const ImVec2& r_max, bool clip = true);// is mouse hovering given bounding rect (in screen space). clipped by current clipping settings, but disregarding of other consideration of focus/window ordering/popup-block.
     IMGUI_API bool          IsMousePosValid(const ImVec2* mouse_pos = NULL);                    // by convention we use (-FLT_MAX,-FLT_MAX) to denote that there is no mouse available
-    IMGUI_API bool          IsAnyMouseDown();                                                   // is any mouse button held?
+    IMGUI_API bool          IsAnyMouseDown();                                                   // [WILL OBSOLETE] is any mouse button held? This was designed for backends, but prefer having backend maintain a mask of held mouse buttons, because upcoming input queue system will make this invalid.
     IMGUI_API ImVec2        GetMousePos();                                                      // shortcut to ImGui::GetIO().MousePos provided by user, to be consistent with other calls
     IMGUI_API ImVec2        GetMousePosOnOpeningCurrentPopup();                                 // retrieve mouse position at the time of opening popup we have BeginPopup() into (helper to avoid user backing that value themselves)
     IMGUI_API bool          IsMouseDragging(ImGuiMouseButton button, float lock_threshold = -1.0f);         // is mouse dragging? (if lock_threshold < -1.0f, uses io.MouseDraggingThreshold)