画像デコーダー

AAssetManager* nativeManager = AAssetManager_fromJava(env, jAssets);
const char* file = // Filename
AAsset* asset = AAssetManager_open(nativeManager, file, AASSET_MODE_STREAMING);
AImageDecoder* decoder;
int result = AImageDecoder_createFromAAsset(asset, &decoder);
if (result != ANDROID_IMAGE_DECODER_SUCCESS) {
  // An error occurred, and the file could not be decoded.
}

const AImageDecoderHeaderInfo* info = AImageDecoder_getHeaderInfo(decoder);
int32_t width = AImageDecoderHeaderInfo_getWidth(info);
int32_t height = AImageDecoderHeaderInfo_getHeight(info);
AndroidBitmapFormat format =
       (AndroidBitmapFormat) AImageDecoderHeaderInfo_getAndroidBitmapFormat(info);
size_t stride = AImageDecoder_getMinimumStride(decoder);  // Image decoder does not
                                                          // use padding by default
size_t size = height * stride;
void* pixels = malloc(size);

result = AImageDecoder_decodeImage(decoder, pixels, stride, size);
if (result != ANDROID_IMAGE_DECODER_SUCCESS) {
  // An error occurred, and the file could not be decoded.
}

// We’re done with the decoder, so now it’s safe to delete it.
AImageDecoder_delete(decoder);

// The decoder is no longer accessing the AAsset, so it is safe to
// close it.
AAsset_close(asset);

// Draw the pixels somewhere

// Free the pixels when done drawing with them
free(pixels);