tests: Don't try to load unsupported image types in testclipboard

Requesting certain MIME types (e.g. EPS formats offered by KDE) can be *very* slow, on the order of multiple seconds, due to requiring significant processing. Only try to load image MIME types that SDL is known to support (BMP and PNG).

(cherry picked from commit 32747ceb84aa57dd6ef16f1ed21a724821bd17a1)

test/testclipboard.c

@@ -24,6 +24,11 @@ static const char *mime_types[] = {
     "image/png",
 };
 
+static const char *supported_image_mime_types[] = {
+    "image/bmp",
+    "image/png",
+};
+
 static const void *ClipboardDataCallback(void *userdata, const char *mime_type, size_t *size)
 {
     if (SDL_strcmp(mime_type, "text/plain") == 0) {
@@ -78,9 +83,8 @@ SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
 
     case SDL_EVENT_CLIPBOARD_UPDATE:
         if (event->clipboard.num_mime_types > 0) {
-            int i;
             SDL_Log("Clipboard updated:");
-            for (i = 0; event->clipboard.mime_types[i]; ++i) {
+            for (int i = 0; event->clipboard.mime_types[i]; ++i) {
                 SDL_Log("    %s", event->clipboard.mime_types[i]);
             }
         } else {
@@ -132,46 +136,66 @@ static float PrintPrimarySelectionText(float x, float y)
     return 0.0f;
 }
 
+static bool IsImageMIMETypeSupported(const char *mime_type)
+{
+    for (int i = 0; i < SDL_arraysize(supported_image_mime_types); ++i) {
+        if (SDL_strcmp(mime_type, supported_image_mime_types[i]) == 0) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
 static float PrintClipboardImage(float x, float y, const char *mime_type)
 {
+    float h = 0.0f;
+
     /* We don't actually need to read this data each frame, but this is a simple example */
-    size_t size;
-    void *data = SDL_GetClipboardData(mime_type, &size);
-    if (data) {
-        float w = 0.0f, h = 0.0f;
-        bool rendered = false;
-        SDL_IOStream *stream = SDL_IOFromConstMem(data, size);
-        if (stream) {
-            SDL_Surface *surface = SDL_LoadSurface_IO(stream, false);
-            if (surface) {
-                SDL_Texture *texture = SDL_CreateTextureFromSurface(renderer, surface);
-                if (texture) {
-                    SDL_GetTextureSize(texture, &w, &h);
-
-                    SDL_FRect dst = { x, y, w, h };
-                    rendered = SDL_RenderTexture(renderer, texture, NULL, &dst);
-                    SDL_DestroyTexture(texture);
+    if (IsImageMIMETypeSupported(mime_type)) {
+        size_t size;
+        void *data = SDL_GetClipboardData(mime_type, &size);
+        if (data) {
+            float w = 0.0f;
+            bool rendered = false;
+            SDL_IOStream *stream = SDL_IOFromConstMem(data, size);
+            if (stream) {
+                SDL_Surface *surface = SDL_LoadSurface_IO(stream, false);
+                if (surface) {
+                    SDL_Texture *texture = SDL_CreateTextureFromSurface(renderer, surface);
+                    if (texture) {
+                        SDL_GetTextureSize(texture, &w, &h);
+
+                        SDL_FRect dst = { x, y, w, h };
+                        rendered = SDL_RenderTexture(renderer, texture, NULL, &dst);
+                        SDL_DestroyTexture(texture);
+                    }
+                    SDL_DestroySurface(surface);
                 }
-                SDL_DestroySurface(surface);
+                SDL_CloseIO(stream);
             }
-            SDL_CloseIO(stream);
-        }
-        if (!rendered) {
-            SDL_RenderDebugText(renderer, x, y, SDL_GetError());
+            if (!rendered) {
+                SDL_RenderDebugText(renderer, x, y, SDL_GetError());
+                h += SDL_DEBUG_TEXT_FONT_CHARACTER_SIZE + 2.0f;
+            }
+            SDL_free(data);
+        } else {
+            SDL_RenderDebugText(renderer, x, y, "No data returned");
+            h += SDL_DEBUG_TEXT_FONT_CHARACTER_SIZE + 2.0f;
         }
-        SDL_free(data);
-        return h + 2.0f;
+    } else {
+        SDL_RenderDebugText(renderer, x, y, "Unsupported MIME type");
+        h += SDL_DEBUG_TEXT_FONT_CHARACTER_SIZE + 2.0f;
     }
-    return 0.0f;
+
+    return h + 2.0f;
 }
 
 static float PrintClipboardContents(float x, float y)
 {
     char **clipboard_mime_types = SDL_GetClipboardMimeTypes(NULL);
     if (clipboard_mime_types) {
-        int i;
-
-        for (i = 0; clipboard_mime_types[i]; ++i) {
+        for (int i = 0; clipboard_mime_types[i]; ++i) {
             const char *mime_type = clipboard_mime_types[i];
             SDL_RenderDebugText(renderer, x, y, mime_type);
             y += SDL_DEBUG_TEXT_FONT_CHARACTER_SIZE + 2;
@@ -184,7 +208,7 @@ static float PrintClipboardContents(float x, float y)
         SDL_free(clipboard_mime_types);
     }
 
-    return y;
+    return y + 2.0f;
 }
 
 SDL_AppResult SDL_AppIterate(void *appstate)