Bitmap设置圆角（任意角）

public class BitmapFillet {


    public static final int CORNER_NONE = 0;
    public static final int CORNER_TOP_LEFT = 1;
    public static final int CORNER_TOP_RIGHT = 1 << 1;
    public static final int CORNER_BOTTOM_LEFT = 1 << 2;
    public static final int CORNER_BOTTOM_RIGHT = 1 << 3;
    public static final int CORNER_ALL = CORNER_TOP_LEFT | CORNER_TOP_RIGHT | CORNER_BOTTOM_LEFT | CORNER_BOTTOM_RIGHT;
    public static final int CORNER_TOP = CORNER_TOP_LEFT | CORNER_TOP_RIGHT;
    public static final int CORNER_BOTTOM = CORNER_BOTTOM_LEFT | CORNER_BOTTOM_RIGHT;
    public static final int CORNER_LEFT = CORNER_TOP_LEFT | CORNER_BOTTOM_LEFT;
    public static final int CORNER_RIGHT = CORNER_TOP_RIGHT | CORNER_BOTTOM_RIGHT;


    public static Bitmap fillet(Bitmap bitmap, int roundPx, int corners) {
        try {
            // 其原理就是：先建立一个与图片大小相同的透明的Bitmap画板
            // 然后在画板上画出一个想要的形状的区域。
            // 最后把源图片帖上。
            final int width = bitmap.getWidth();
            final int height = bitmap.getHeight();


            Bitmap paintingBoard = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
            Canvas canvas = new Canvas(paintingBoard);
            canvas.drawARGB(Color.TRANSPARENT, Color.TRANSPARENT, Color.TRANSPARENT, Color.TRANSPARENT);


            final Paint paint = new Paint();
            paint.setAntiAlias(true);
            paint.setColor(Color.BLACK);


            //画出4个圆角
            final RectF rectF = new RectF(0, 0, width, height);
            canvas.drawRoundRect(rectF, roundPx, roundPx, paint);


            //把不需要的圆角去掉
            int notRoundedCorners = corners ^ CORNER_ALL;
            if ((notRoundedCorners & CORNER_TOP_LEFT) != 0) {
                clipTopLeft(canvas,paint,roundPx,width,height);
            }
            if ((notRoundedCorners & CORNER_TOP_RIGHT) != 0) {
                clipTopRight(canvas, paint, roundPx, width, height);
            }
            if ((notRoundedCorners & CORNER_BOTTOM_LEFT) != 0) {
                clipBottomLeft(canvas,paint,roundPx,width,height);
            }
            if ((notRoundedCorners & CORNER_BOTTOM_RIGHT) != 0) {
                clipBottomRight(canvas, paint, roundPx, width, height);
            }
            paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));


            //帖子图
            final Rect src = new Rect(0, 0, width, height);
            final Rect dst = src;
            canvas.drawBitmap(bitmap, src, dst, paint);
            return paintingBoard;
        } catch (Exception exp) {
            return bitmap;
        }
    }


    private static void clipTopLeft(final Canvas canvas, final Paint paint, int offset, int width, int height) {
        final Rect block = new Rect(0, 0, offset, offset);
        canvas.drawRect(block, paint);
    }


    private static void clipTopRight(final Canvas canvas, final Paint paint, int offset, int width, int height) {
        final Rect block = new Rect(width - offset, 0, width, offset);
        canvas.drawRect(block, paint);
    }


    private static void clipBottomLeft(final Canvas canvas, final Paint paint, int offset, int width, int height) {
        final Rect block = new Rect(0, height - offset, offset, height);
        canvas.drawRect(block, paint);
    }


    private static void clipBottomRight(final Canvas canvas, final Paint paint, int offset, int width, int height) {
        final Rect block = new Rect(width - offset, height - offset, width, height);
        canvas.drawRect(block, paint);
    }
}