hint for which system cursor to use as default

Co-Authored-By: Sam Lantinga <[e-mail]>

include/SDL3/SDL_hints.h

···
 #define SDL_HINT_MOUSE_DOUBLE_CLICK_TIME "SDL_MOUSE_DOUBLE_CLICK_TIME"
 
 /**
+ * A variable setting which system cursor to use as the default cursor.
+ * This should be an integer corresponding to the SDL_SystemCursor enum.
+ * The default value is zero (SDL_SYSTEM_CURSOR_DEFAULT).
+ *
+ * This hint needs to be set before SDL_Init().
+ *
+ * \since This hint is available since SDL 3.1.3.
+ */
+#define SDL_HINT_MOUSE_DEFAULT_SYSTEM_CURSOR "SDL_MOUSE_DEFAULT_SYSTEM_CURSOR"
+
+/**
  * A variable controlling whether warping a hidden mouse cursor will activate
  * relative mouse mode.
  *

src/events/SDL_mouse.c

···
     }
 }
 
+SDL_SystemCursor SDL_GetDefaultSystemCursor(void) 
+{
+    SDL_SystemCursor id = SDL_SYSTEM_CURSOR_DEFAULT;
+    const char *value = SDL_GetHint(SDL_HINT_MOUSE_DEFAULT_SYSTEM_CURSOR);
+    if (value) {
+        int index = SDL_atoi(value);
+        if (0 <= index && index < (int)SDL_SYSTEM_CURSOR_COUNT) {
+            id = (SDL_SystemCursor)index;
+        }
+    }
+    return id;
+}
+
 SDL_Mouse *SDL_GetMouse(void)
 {
     return &SDL_mouse;

src/events/SDL_mouse_c.h

···
 // Set the default mouse cursor
 extern void SDL_SetDefaultCursor(SDL_Cursor *cursor);
 
+// Get the preferred default system cursor
+extern SDL_SystemCursor SDL_GetDefaultSystemCursor(void);
+
 // Set the mouse focus window
 extern void SDL_SetMouseFocus(SDL_Window *window);
 

src/video/android/SDL_androidmouse.c

···
 
 static SDL_Cursor *Android_CreateDefaultCursor(void)
 {
-    return Android_WrapCursor(0, SDL_SYSTEM_CURSOR_DEFAULT);
+    SDL_SystemCursor id = SDL_GetDefaultSystemCursor();
+    return Android_WrapCursor(0, id);
 }
 
 static SDL_Cursor *Android_CreateCursor(SDL_Surface *surface, int hot_x, int hot_y)

src/video/cocoa/SDL_cocoamouse.m

···
 }
 @end
 
-static SDL_Cursor *Cocoa_CreateDefaultCursor(void)
-{
-    @autoreleasepool {
-        NSCursor *nscursor;
-        SDL_Cursor *cursor = NULL;
-
-        nscursor = [NSCursor arrowCursor];
-
-        if (nscursor) {
-            cursor = SDL_calloc(1, sizeof(*cursor));
-            if (cursor) {
-                cursor->internal = (void *)CFBridgingRetain(nscursor);
-            }
-        }
-
-        return cursor;
-    }
-}
-
 static SDL_Cursor *Cocoa_CreateCursor(SDL_Surface *surface, int hot_x, int hot_y)
 {
     @autoreleasepool {
···
 
         return cursor;
     }
+}
+
+static SDL_Cursor *Cocoa_CreateDefaultCursor(void)
+{
+    SDL_SystemCursor id = SDL_GetDefaultSystemCursor();
+    return Cocoa_CreateSystemCursor(id);
 }
 
 static void Cocoa_FreeCursor(SDL_Cursor *cursor)

src/video/emscripten/SDL_emscriptenmouse.c

···
 
 static SDL_Cursor *Emscripten_CreateDefaultCursor(void)
 {
-    return Emscripten_CreateCursorFromString("default", false);
+    SDL_SystemCursor id = SDL_GetDefaultSystemCursor();
+    const char *cursor_name = SDL_GetCSSCursorName(id, NULL);
+    return Emscripten_CreateCursorFromString(cursor_name, false);
 }
 
 EM_JS_DEPS(sdlmouse, "$stringToUTF8,$UTF8ToString");

src/video/haiku/SDL_bvideo.cc

···
 
 static SDL_Cursor * HAIKU_CreateDefaultCursor()
 {
-    return HAIKU_CreateSystemCursor(SDL_SYSTEM_CURSOR_DEFAULT);
+    SDL_SystemCursor id = SDL_GetDefaultSystemCursor();
+    return HAIKU_CreateSystemCursor(id);
 }
 
 static void HAIKU_FreeCursor(SDL_Cursor * cursor)

src/video/wayland/SDL_waylandmouse.c

···
 
 static SDL_Cursor *Wayland_CreateDefaultCursor(void)
 {
-    return Wayland_CreateSystemCursor(SDL_SYSTEM_CURSOR_DEFAULT);
+    SDL_SystemCursor id = SDL_GetDefaultSystemCursor();
+    return Wayland_CreateSystemCursor(id);
 }
 
 static void Wayland_FreeCursorData(SDL_CursorData *d)

src/video/windows/SDL_windowsmouse.c

···
     return cursor;
 }
 
-static SDL_Cursor *WIN_CreateDefaultCursor(void)
-{
-    return WIN_CreateCursorAndData(LoadCursor(NULL, IDC_ARROW));
-}
-
 static bool IsMonochromeSurface(SDL_Surface *surface)
 {
     int x, y;
···
         break;
     }
     return WIN_CreateCursorAndData(LoadCursor(NULL, name));
+}
+
+static SDL_Cursor *WIN_CreateDefaultCursor(void)
+{
+    SDL_SystemCursor id = SDL_GetDefaultSystemCursor();
+    return WIN_CreateSystemCursor(id);
 }
 
 static void WIN_FreeCursor(SDL_Cursor *cursor)

src/video/x11/SDL_x11mouse.c

···
     return cursor;
 }
 
-static SDL_Cursor *X11_CreateDefaultCursor(void)
-{
-    // None is used to indicate the default cursor
-    return X11_CreateCursorAndData(None);
-}
-
 #ifdef SDL_VIDEO_DRIVER_X11_XCURSOR
 static Cursor X11_CreateXCursorCursor(SDL_Surface *surface, int hot_x, int hot_y)
 {
···
     }
 
     return cursor;
+}
+
+static SDL_Cursor *X11_CreateDefaultCursor(void)
+{
+    SDL_SystemCursor id = SDL_GetDefaultSystemCursor();
+    return X11_CreateSystemCursor(id);
 }
 
 static void X11_FreeCursor(SDL_Cursor *cursor)