图片的合成_改变图片颜色形成老照片水彩画效果

就是利用ColorMatrx来进行改变

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        try {
            if (data != null) {
                // 得到点击图片的uri
                Uri uri = data.getData();
                //原图
                Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));
                iv.setImageBitmap(bitmap);
                //原图的拷贝
                Bitmap alterBitmap  = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight()-30, bitmap.getConfig());
                //以拷贝图片的为模板创建一个画布
                Canvas canvas = new Canvas(alterBitmap);
                Matrix matrix = new Matrix();

                ColorMatrix cm = new ColorMatrix();
/*                cm.set(new float[] {
                1, 3, 0, 0, 0,
                0, 2, 0, 0, 0,
                0, 0, 3, 0, 0,
                0, 0, 0, 1, 0
                });*/
                cm.setSaturation(0.5f);


                
                
                Paint paint = new Paint();
                paint.setColorFilter(new ColorMatrixColorFilter(cm));
                
                paint.setAntiAlias(true);//在算法上 取消锯齿
                canvas.drawBitmap(bitmap, matrix, paint);
                iv_copy.setImageBitmap(alterBitmap);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        super.onActivityResult(requestCode, resultCode, data);
    }