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feat(emscripten): Add SDL_SetWindowIcon implementation. #14490

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Merged
merged 3 commits into from
Nov 21, 2025
+52 −2
Merged

feat(emscripten): Add SDL_SetWindowIcon implementation. #14490

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1f58216
emscripten: Add SDL_SetWindowIcon implementation.
ej-sanmartin Nov 20, 2025
d560479
Explicitly set link to image/type
ej-sanmartin Nov 20, 2025
937e236
Update emscripten SDL_SetWindowIcon implementation to use native SDL_…
ej-sanmartin Nov 21, 2025
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54 changes: 52 additions & 2 deletions src/video/emscripten/SDL_emscriptenvideo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ static void Emscripten_DestroyWindow(SDL_VideoDevice *_this, SDL_Window *window)
static SDL_FullscreenResult Emscripten_SetWindowFullscreen(SDL_VideoDevice *_this, SDL_Window *window, SDL_VideoDisplay *display, SDL_FullscreenOp fullscreen);
static void Emscripten_PumpEvents(SDL_VideoDevice *_this);
static void Emscripten_SetWindowTitle(SDL_VideoDevice *_this, SDL_Window *window);
static bool Emscripten_SetWindowIcon(SDL_VideoDevice *_this, SDL_Window *window, SDL_Surface *icon);

static bool pumpevents_has_run = false;
static int pending_swap_interval = -1;
Expand Down Expand Up @@ -157,8 +158,8 @@ static SDL_VideoDevice *Emscripten_CreateDevice(void)

device->CreateSDLWindow = Emscripten_CreateWindow;
device->SetWindowTitle = Emscripten_SetWindowTitle;
/*device->SetWindowIcon = Emscripten_SetWindowIcon;
device->SetWindowPosition = Emscripten_SetWindowPosition;*/
device->SetWindowIcon = Emscripten_SetWindowIcon;
/*device->SetWindowPosition = Emscripten_SetWindowPosition;*/
device->SetWindowSize = Emscripten_SetWindowSize;
device->SetWindowResizable = Emscripten_SetWindowResizable;
/*device->ShowWindow = Emscripten_ShowWindow;
Expand Down Expand Up @@ -716,4 +717,53 @@ static void Emscripten_SetWindowTitle(SDL_VideoDevice *_this, SDL_Window *window
emscripten_set_window_title(window->title);
}

static bool Emscripten_SetWindowIcon(SDL_VideoDevice *_this, SDL_Window *window, SDL_Surface *icon)
{
// Create dynamic memory stream for PNG encoding
SDL_IOStream *stream = SDL_IOFromDynamicMem();
if (!stream) {
return false;
}

// Encode icon to PNG using SDL's native PNG encoder
if (!SDL_SavePNG_IO(icon, stream, false)) {
SDL_CloseIO(stream);
return false;
}

// Get the PNG data from the stream
void *png_data = SDL_GetPointerProperty(
SDL_GetIOProperties(stream),
SDL_PROP_IOSTREAM_DYNAMIC_MEMORY_POINTER,
NULL
);
size_t png_size = (size_t)SDL_GetIOSize(stream);

// Pass PNG data to JavaScript
MAIN_THREAD_EM_ASM({
var pngData = HEAPU8.subarray($0, $0 + $1);
var blob = new Blob([pngData], {type: 'image/png'});
var url = URL.createObjectURL(blob);

// Set as favicon (create link element if it doesn't exist)
var link = document.querySelector("link[rel~='icon']");
if (!link) {
link = document.createElement('link');
link.rel = 'icon';
link.type = 'image/png';
document.head.appendChild(link);
}

// Revoke old URL if it exists to prevent memory leaks
if (link.href && link.href.startsWith('blob:')) {
URL.revokeObjectURL(link.href);
}

link.href = url;
}, png_data, png_size);

SDL_CloseIO(stream);
return true;
}

#endif // SDL_VIDEO_DRIVER_EMSCRIPTEN
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