Android绘制圆角图片

public class PhotoTestActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        ImageView image = (ImageView)findViewById(R.id.image);
        Bitmap photo = BitmapFactory.decodeResource(getResources(), R.drawable.test);
        image.setImageBitmap(createFramedPhoto(500,400,photo,50));
    }

   /**
     *
     * @param x 图像的宽度
     * @param y 图像的高度
     * @param image 源图片
     * @param outerRadiusRat 圆角的大小
     * @return 圆角图片
     */
    Bitmap createFramedPhoto(int x, int y, Bitmap image, float outerRadiusRat) {

        //根据源文件新建一个darwable对象
        Drawable imageDrawable = new BitmapDrawable(image);

        // 新建一个新的输出图片
        Bitmap output = Bitmap.createBitmap(x, y, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        // 新建一个矩形
        RectF outerRect = new RectF(0, 0, x, y);

        // 产生一个红色的圆角矩形
        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.RED);
        canvas.drawRoundRect(outerRect, outerRadiusRat, outerRadiusRat, paint);

        // 将源图片绘制到这个圆角矩形上
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        imageDrawable.setBounds(0, 0, x, y);
        canvas.saveLayer(outerRect, paint, Canvas.ALL_SAVE_FLAG);
        imageDrawable.draw(canvas);
        canvas.restore();
        return output;
    }
}