BitmapFactory.Options&bitmap加灰色遮罩

----- 代码

① BitmapFactory.Options仅读取图片的尺寸参数的正确使用姿势

② 给bitmap加灰色遮罩

private void draw2layer(ImageView imageViewBlur2) {

        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(getResources(), R.drawable.icon, options);
        int outWidth = options.outWidth;
        int outHeight = options.outHeight;

        Log.i(tag, "draw2layer: outWidth = " + outWidth + " ; outHeoght = " + outHeight);

        Bitmap bitmap = Bitmap.createBitmap(outWidth, outHeight, Bitmap.Config.RGB_565);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.icon, null), 0, 0, null);
        Canvas canvas1 = new Canvas(bitmap);
        canvas1.drawColor(0x33000000);
        imageViewBlur2.setImageBitmap(bitmap);
    }

----- 效果展示

-------未加灰色遮罩代码

        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(getResources(), R.drawable.icon, options);
        int outWidth = options.outWidth;
        int outHeight = options.outHeight;

        Log.i(tag, "draw2layer: outWidth = " + outWidth + " ; outHeoght = " + outHeight);

        Bitmap bitmap = Bitmap.createBitmap(outWidth, outHeight, Bitmap.Config.RGB_565);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.icon, null), 0, 0, null);
        imageView.setImageBitmap(bitmap);

----- 实现灰色遮罩的另外一种思路

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