Backends: SDL2, SDL3: Use display bounds when SDL_GetDisplayUsableBounds() fails or return a zero size. (#8415, #3457)

Analoguous to aa8e09d7f1 for GLFW.

backends/imgui_impl_sdl2.cpp

@@ -26,6 +26,7 @@
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-02-25: [Docking] Revert to use SDL_GetDisplayBounds() for WorkPos/WorkRect if SDL_GetDisplayUsableBounds() failed.
 //  2025-02-21: [Docking] Update monitors and work areas information every frame, as the later may change regardless of monitor changes. (#8415)
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-02-10: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn handler.
@@ -868,9 +869,11 @@ static void ImGui_ImplSDL2_UpdateMonitors()
         monitor.MainPos = monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
         monitor.MainSize = monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
 #if SDL_HAS_USABLE_DISPLAY_BOUNDS
-        SDL_GetDisplayUsableBounds(n, &r);
-        monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
-        monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        if (SDL_GetDisplayUsableBounds(n, &r) == 0 && r.w > 0 && r.h > 0)
+        {
+            monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+            monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        }
 #endif
 #if SDL_HAS_PER_MONITOR_DPI
         // FIXME-VIEWPORT: On MacOS SDL reports actual monitor DPI scale, ignoring OS configuration. We may want to set

backends/imgui_impl_sdl3.cpp

@@ -24,6 +24,7 @@
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-02-25: [Docking] Revert to use SDL_GetDisplayBounds() for WorkPos/WorkRect if SDL_GetDisplayUsableBounds() failed.
 //  2025-02-21: [Docking] Update monitors and work areas information every frame, as the later may change regardless of monitor changes. (#8415)
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-02-10: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn handler.
@@ -832,9 +833,11 @@ static void ImGui_ImplSDL3_UpdateMonitors()
         SDL_GetDisplayBounds(display_id, &r);
         monitor.MainPos = monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
         monitor.MainSize = monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
-        SDL_GetDisplayUsableBounds(display_id, &r);
-        monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
-        monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        if (SDL_GetDisplayUsableBounds(display_id, &r) && r.w > 0 && r.h > 0)
+        {
+            monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+            monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        }
         // FIXME-VIEWPORT: On MacOS SDL reports actual monitor DPI scale, ignoring OS configuration. We may want to set
         //  DpiScale to cocoa_window.backingScaleFactor here.
         monitor.DpiScale = SDL_GetDisplayContentScale(display_id);

docs/CHANGELOG.txt

@@ -87,8 +87,10 @@ Other changes:
   (busy/wait/hourglass shape, with or without an arrow cursor).
 - Demo: Combos: demonstrate a very simple way to add a filter to a combo,
   by showing the filter inside the combo contents. (#718)
-- Backends: SDL2, SDL3:  Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn
+- Backends: SDL2, SDL3: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn
   handler. (#7660) [@achabense]
+- Backends: SDL2, SDL3: Use display bounds when SDL_GetDisplayUsableBounds() 
+  fails or return a zero size. (#8415, #3457)
 - Backends: SDL2, SDL3, Win32, Allegro5: Added support for ImGuiMouseCursor_Wait
   and ImGuiMouseCursor_Progress cursors.
 - Backends: OpenGL3: Lazily reinitialize embedded GL loader for when calling backend