Instagram的Tilt Shift动画在Android中

Question

我想创建一个类似于Instagram Tilt Shift（径向/线性）的动画，我试图从现有图像创建一个模糊的位图，并在动画开始和停止时更改imageView源。但它缓慢且不顺畅。

public class BlurMaskHandler extends AsyncTask<Integer,Integer,Bitmap> {

    @Override
    protected Bitmap doInBackground(Integer... drawable) {



            Bitmap bitmapMaster = BitmapFactory.decodeResource(getResources(), drawable[0]);

            int w = bitmapMaster.getWidth();
            int h = bitmapMaster.getHeight();
            RectF rectF = new RectF(0,0,w,h);

            float blurRadius = 500.0f;

           Bitmap bitmapResult = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
            Canvas canvasResult = new Canvas(bitmapResult);


            Paint blurPaintOuter = new Paint();
            blurPaintOuter.setColor(0xFFffffff);
            blurPaintOuter.setMaskFilter(new
                    BlurMaskFilter(blurRadius, BlurMaskFilter.Blur.INNER));
            canvasResult.drawBitmap(bitmapMaster, 0, 0, blurPaintOuter);



            Paint blurPaintInner = new Paint();
            blurPaintInner.setColor(0x80ffffff);
            blurPaintInner.setMaskFilter(new
                    BlurMaskFilter(blurRadius, BlurMaskFilter.Blur.INNER));
            canvasResult.drawRect(rectF, blurPaintInner);

            return bitmapResult;

    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        super.onPostExecute(bitmap);

        bitmapView = bitmap;




    }
}