RawImage -> ImageData; report errors with null

codecs/avif/dec/avif_dec.cpp

@@ -4,56 +4,47 @@
 
 using namespace emscripten;
 
-class RawImage {
- public:
-  val buffer;
-  uint32_t width;
-  uint32_t height;
+thread_local const val Uint8ClampedArray = val::global("Uint8ClampedArray");
+thread_local const val ImageData = val::global("ImageData");
 
-  RawImage(val b, uint32_t w, uint32_t h) : buffer(b), width(w), height(h) {}
-};
-
-RawImage decode(std::string avifimage) {
+val decode(std::string avifimage) {
   // point raw.data and raw.size to the contents of an .avif(s)
-  avifROData raw;
-  raw.data = (uint8_t*)avifimage.c_str();
-  raw.size = avifimage.length();
+  avifROData raw = {
+    .data = (uint8_t*)avifimage.c_str(),
+    .size = avifimage.length()
+  };
 
   avifImage* image = avifImageCreateEmpty();
   avifDecoder* decoder = avifDecoderCreate();
   avifResult decodeResult = avifDecoderRead(decoder, image, &raw);
   // image is an independent copy of decoded data, decoder may be destroyed here
   avifDecoderDestroy(decoder);
-  if (decodeResult != AVIF_RESULT_OK) {
-    return RawImage(val::null(), -1, -1);
+
+  val result = val::null();
+
+  if (decodeResult == AVIF_RESULT_OK) {
+    // Convert to interleaved RGB(A)/BGR(A) using a libavif-allocated buffer.
+    avifRGBImage rgb;
+    avifRGBImageSetDefaults(&rgb, image);  // Defaults to AVIF_RGB_FORMAT_RGBA which is what we want.
+    rgb.depth = 8;  // Does not need to match image->depth. We always want 8-bit pixels.
+
+    avifRGBImageAllocatePixels(&rgb);
+    avifImageYUVToRGB(image, &rgb);
+
+    // We want to create a *copy* of the decoded data to be owned by the JavaScript side.
+    // For that, we perform `new Uint8Array(wasmMemBuffer, wasmPtr, wasmSize).slice()`:
+    result = ImageData.new_(Uint8ClampedArray.new_(typed_memory_view(rgb.rowBytes * rgb.height, rgb.pixels)), rgb.width, rgb.height);
+
+    // Now we can safely free the RGB pixels:
+    avifRGBImageFreePixels(&rgb);
   }
 
-  // Convert to interleaved RGB(A)/BGR(A) using a libavif-allocated buffer.
-  avifRGBImage rgb;
-  avifRGBImageSetDefaults(&rgb, image);  // Defaults to AVIF_RGB_FORMAT_RGBA which is what we want.
-  rgb.depth = 8;  // Does not need to match image->depth. We always want 8-bit pixels.
-
-  avifRGBImageAllocatePixels(&rgb);
-  avifImageYUVToRGB(image, &rgb);
-
   // Image has been converted to RGB, we don't need the original anymore.
   avifImageDestroy(image);
 
-  // We want to create a *copy* of the decoded data to be owned by the JavaScript side.
-  // For that, we perform `new Uint8Array(wasmMemBuffer, wasmPtr, wasmSize).slice()`:
-  auto result = val(typed_memory_view(rgb.rowBytes * rgb.height, rgb.pixels)).call<val>("slice");
-
-  // Now we can safely free the RGB pixels:
-  avifRGBImageFreePixels(&rgb);
-
-  return RawImage(result, rgb.width, rgb.height);
+  return result;
 }
 
 EMSCRIPTEN_BINDINGS(my_module) {
-  class_<RawImage>("RawImage")
-      .property("buffer", &RawImage::buffer)
-      .property("width", &RawImage::width)
-      .property("height", &RawImage::height);
-
   function("decode", &decode);
 }