Windows allows windows to be resized to zero height.

Changed the window client rect validation to take this into account.

Fixes https://github.com/libsdl-org/SDL/issues/9796

src/core/windows/SDL_windows.c

@@ -330,10 +330,10 @@ void WIN_RectToRECT(const SDL_Rect *sdlrect, RECT *winrect)
     winrect->bottom = sdlrect->y + sdlrect->h - 1;
 }
 
-BOOL WIN_IsRectEmpty(const RECT *rect)
+bool WIN_WindowRectValid(const RECT *rect)
 {
-    // Calculating this manually because Xbox does not support Win32 IsRectEmpty.
+    // A window can be resized to zero height, but not zero width
-    return (rect->right <= rect->left) || (rect->bottom <= rect->top);
+    return (rect->right > 0);
 }
 
 // Some GUIDs we need to know without linking to libraries that aren't available before Vista.

src/core/windows/SDL_windows.h

@@ -156,8 +156,8 @@ extern BOOL WIN_IsEqualIID(REFIID a, REFIID b);
 extern void WIN_RECTToRect(const RECT *winrect, SDL_Rect *sdlrect);
 extern void WIN_RectToRECT(const SDL_Rect *sdlrect, RECT *winrect);
 
-// Returns true if the rect is empty
+// Returns false if a window client rect is not valid
-extern BOOL WIN_IsRectEmpty(const RECT *rect);
+bool WIN_WindowRectValid(const RECT *rect);
 
 extern SDL_AudioFormat SDL_WaveFormatExToSDLFormat(WAVEFORMATEX *waveformat);
 

src/video/windows/SDL_windowsevents.c

@@ -1792,7 +1792,7 @@ LRESULT CALLBACK WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lPara
         }
 
         if (!data->disable_move_size_events) {
-            if (GetClientRect(hwnd, &rect) && !WIN_IsRectEmpty(&rect)) {
+            if (GetClientRect(hwnd, &rect) && WIN_WindowRectValid(&rect)) {
                 ClientToScreen(hwnd, (LPPOINT) &rect);
                 ClientToScreen(hwnd, (LPPOINT) &rect + 1);
 
@@ -1804,7 +1804,7 @@ LRESULT CALLBACK WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lPara
             }
 
             // Moving the window from one display to another can change the size of the window (in the handling of SDL_EVENT_WINDOW_MOVED), so we need to re-query the bounds
-            if (GetClientRect(hwnd, &rect) && !WIN_IsRectEmpty(&rect)) {
+            if (GetClientRect(hwnd, &rect) && WIN_WindowRectValid(&rect)) {
                 w = rect.right;
                 h = rect.bottom;
 
@@ -2084,7 +2084,7 @@ LRESULT CALLBACK WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lPara
                 RECT rect;
                 float x, y;
 
-                if (!GetClientRect(hwnd, &rect) || WIN_IsRectEmpty(&rect)) {
+                if (!GetClientRect(hwnd, &rect) || !WIN_WindowRectValid(&rect)) {
                     if (inputs) {
                         SDL_small_free(inputs, isstack);
                     }

src/video/windows/SDL_windowswindow.c

@@ -535,7 +535,7 @@ static bool SetupWindowData(SDL_VideoDevice *_this, SDL_Window *window, HWND hwn
     }
     if (!(window->flags & SDL_WINDOW_MINIMIZED)) {
         RECT rect;
-        if (GetClientRect(hwnd, &rect) && !WIN_IsRectEmpty(&rect)) {
+        if (GetClientRect(hwnd, &rect) && WIN_WindowRectValid(&rect)) {
             int w = rect.right;
             int h = rect.bottom;
 
@@ -1062,7 +1062,7 @@ void WIN_GetWindowSizeInPixels(SDL_VideoDevice *_this, SDL_Window *window, int *
     HWND hwnd = data->hwnd;
     RECT rect;
 
-    if (GetClientRect(hwnd, &rect) && !WIN_IsRectEmpty(&rect)) {
+    if (GetClientRect(hwnd, &rect) && WIN_WindowRectValid(&rect)) {
         *w = rect.right;
         *h = rect.bottom;
     } else if (window->last_pixel_w && window->last_pixel_h) {