Android 创建图像倒影

public void createReflectedImages() {
  int reflectionGap = 4;

  Bitmap originalImage = BitmapFactory.decodeResource(getResources(), R.drawable.qq);
  int width = originalImage.getWidth();
  int height = originalImage.getHeight();

  Matrix matrix = new Matrix();
  matrix.preScale(1, -1);
  
  Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0, height / 2, width, height / 2, matrix, false);

  Bitmap bitmapWithReflection = Bitmap.createBitmap(width, (height + height / 2 + reflectionGap), Config.ARGB_8888);
  Canvas canvas = new Canvas(bitmapWithReflection);
  
  canvas.drawBitmap(originalImage, 0, 0, null);
  Paint deafaultPaint = new Paint();
  canvas.drawRect(0, height, width, height + reflectionGap, deafaultPaint);
  canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

  Paint paint = new Paint();
  LinearGradient shader = new LinearGradient(0, originalImage.getHeight(), 0, bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);
  paint.setShader(shader);
  paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
  canvas.drawRect(0, height + reflectionGap, width, bitmapWithReflection.getHeight() + reflectionGap, paint);

  imageView.setImageBitmap(bitmapWithReflection);
 }