bool SimpleCanvas::onPaint()
{
if (!mOffScreenBM)
setBitmapSize(clientSizeX(), clientSizeY());
// Copy the off-screen bitmap onto the screen
SIZE sizeOfBM;
GetBitmapDimensionEx(mOffScreenBM, &sizeOfBM);
BitBlt(DC(), 0, 0, sizeOfBM.cx, sizeOfBM.cy,
offScreenDC(), 0, 0, SRCCOPY);
// Fill any unused area with some default colour
RECT fillX = { sizeOfBM.cx, 0, std::max((int)sizeOfBM.cx, clientSizeX()), clientSizeY() };
RECT fillY = { 0, sizeOfBM.cy, clientSizeX(), std::max((int)sizeOfBM.cy, clientSizeY()) };
FillRect(DC(), &fillX, 0);
FillRect(DC(), &fillY, 0);
return true;
}
jobject doDecode(
JNIEnv* env,
uint8_t* encoded_image,
unsigned encoded_image_length,
jobject bitmapOptions,
jfloat scale) {
// Options manipulation is taken from https://github.com/android/platform_frameworks_base/blob/master/core/jni/android/graphics/BitmapFactory.cpp
int image_width = 0;
int image_height = 0;
jobject bitmap = nullptr;
WebPGetInfo(
encoded_image,
encoded_image_length,
&image_width,
&image_height);
WebPDecoderConfig config;
WebPInitDecoderConfig(&config);
if ((bitmapOptions != nullptr) &&
(setOutDimensions(env, bitmapOptions, image_width, image_height))) {
return {};
}
if (scale != 1.0f) {
image_width = int(image_width * scale + 0.5f);
image_height = int(image_height * scale + 0.5f);
config.options.use_scaling = 1;
config.options.scaled_width = image_width;
config.options.scaled_height = image_height;
}
bitmap = createBitmap(env, image_width, image_height, bitmapOptions);
RETURN_NULL_IF_EXCEPTION(env);
void* raw_pixels = nullptr;
int rc = AndroidBitmap_lockPixels(env, bitmap, (void**) &raw_pixels);
if (rc != ANDROID_BITMAP_RESULT_SUCCESS) {
env->ThrowNew(runtimeExceptionClass, "Decode error locking pixels");
return JNI_FALSE;
}
config.output.colorspace = MODE_RGBA;
config.output.u.RGBA.rgba = (uint8_t*) raw_pixels;
config.output.u.RGBA.stride = image_width * 4;
config.output.u.RGBA.size = image_width * image_height * 4;
config.output.is_external_memory = 1;
WebPDecode(encoded_image, encoded_image_length, &config);
rc = AndroidBitmap_unlockPixels(env, bitmap);
if (rc != ANDROID_BITMAP_RESULT_SUCCESS) {
env->ThrowNew(runtimeExceptionClass, "Decode error unlocking pixels");
return {};
}
if (bitmapOptions != nullptr) {
setBitmapSize(env, bitmapOptions, image_width, image_height);
}
return bitmap;
}
