Blur.java 文件源码

public static Bitmap of(Context context, Bitmap source, BlurFactor factor) {
  int width = factor.width / factor.sampling;
  int height = factor.height / factor.sampling;

  if (Helper.hasZero(width, height)) {
    return null;
  }

  Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);

  Canvas canvas = new Canvas(bitmap);
  canvas.scale(1 / (float) factor.sampling, 1 / (float) factor.sampling);
  Paint paint = new Paint();
  paint.setFlags(Paint.FILTER_BITMAP_FLAG | Paint.ANTI_ALIAS_FLAG);
  PorterDuffColorFilter filter =
      new PorterDuffColorFilter(factor.color, PorterDuff.Mode.SRC_ATOP);
  paint.setColorFilter(filter);
  canvas.drawBitmap(source, 0, 0, paint);

  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
    try {
      bitmap = Blur.rs(context, bitmap, factor.radius);
    } catch (RSRuntimeException e) {
      bitmap = Blur.stack(bitmap, factor.radius, true);
    }
  } else {
    bitmap = Blur.stack(bitmap, factor.radius, true);
  }

  if (factor.sampling == BlurFactor.DEFAULT_SAMPLING) {
    return bitmap;
  } else {
    Bitmap scaled = Bitmap.createScaledBitmap(bitmap, factor.width, factor.height, true);
    bitmap.recycle();
    return scaled;
  }
}