MacOS: Added hint to control update of the metal layer's drawable size

include/SDL3/SDL_hints.h

@@ -3594,6 +3594,22 @@ extern "C" {
  */
 #define SDL_HINT_VIDEO_MAC_FULLSCREEN_MENU_VISIBILITY "SDL_VIDEO_MAC_FULLSCREEN_MENU_VISIBILITY"
 
+/**
+ * A variable indicating whether the metal layer drawable size should be
+ * updated for the SDL_EVENT_WINDOW_PIXEL_SIZE_CHANGED event on macOS.
+ *
+ * The variable can be set to the following values:
+ *
+ * - "0": the metal layer drawable size will not be updated
+ *   on the SDL_EVENT_WINDOW_PIXEL_SIZE_CHANGED event.
+ * - "1": the metal layer drawable size will be updated
+ *   on the SDL_EVENT_WINDOW_PIXEL_SIZE_CHANGED event. (default)
+ *
+ * This hint should be set before SDL_Metal_CreateView called.
+ *
+ * \since This hint is available since SDL 3.4.0. */
+#define SDL_HINT_VIDEO_METAL_AUTO_RESIZE_DRAWABLE "SDL_VIDEO_METAL_AUTO_RESIZE_DRAWABLE"
+
 /**
  * A variable controlling whether SDL will attempt to automatically set the
  * destination display to a mode most closely matching that of the previous

src/video/cocoa/SDL_cocoametalview.m

@@ -90,7 +90,9 @@ - (instancetype)initWithFrame:(NSRect)frame
 
         self.layer.opaque = opaque;
 
-        SDL_AddWindowEventWatch(SDL_WINDOW_EVENT_WATCH_EARLY, SDL_MetalViewEventWatch, (__bridge void *)(self));
+        if (SDL_GetHintBoolean(SDL_HINT_VIDEO_METAL_AUTO_RESIZE_DRAWABLE, true)) {
+            SDL_AddWindowEventWatch(SDL_WINDOW_EVENT_WATCH_EARLY, SDL_MetalViewEventWatch, (__bridge void *)(self));
+        }
 
         [self updateDrawableSize];
     }