Android 裁剪图片为圆形图片

现实中相信大家都会发现圆形头像真的感觉棒棒哒，接下来就是圆形的制作，直接上源码：其实就是将一张图片资源bitmap传入这个方法，通过这个方法返回的便是一张圆形图片啦

/**         * 转换图片成圆形         *          * @param bitmap         *            传入Bitmap对象         * @return         */        public Bitmap toRoundBitmap(Bitmap bitmap) {            int width = bitmap.getWidth();            int height = bitmap.getHeight();            float roundPx;            float left, top, right, bottom, dst_left, dst_top, dst_right, dst_bottom;            if (width <= height) {                roundPx = width / 2;                left = 0;                top = 0;                right = width;                bottom = width;                height = width;                dst_left = 0;                dst_top = 0;                dst_right = width;                dst_bottom = width;            } else {                roundPx = height / 2;                float clip = (width - height) / 2;                left = clip;                right = width - clip;                top = 0;                bottom = height;                width = height;                dst_left = 0;                dst_top = 0;                dst_right = height;                dst_bottom = height;            }            Bitmap output = Bitmap.createBitmap(width, height, Config.ARGB_8888);            Canvas canvas = new Canvas(output);            final Paint paint = new Paint();            final Rect src = new Rect((int) left, (int) top, (int) right, (int) bottom);            final Rect dst = new Rect((int) dst_left, (int) dst_top, (int) dst_right, (int) dst_bottom);            final RectF rectF = new RectF(dst);            paint.setAntiAlias(true);// 设置画笔无锯齿            canvas.drawARGB(0, 0, 0, 0); // 填充整个Canvas            // 以下有两种方法画圆,drawRounRect和drawCircle            canvas.drawRoundRect(rectF, roundPx, roundPx, paint);// 画圆角矩形，第一个参数为图形显示区域，第二个参数和第三个参数分别是水平圆角半径和垂直圆角半径。            // canvas.drawCircle(roundPx, roundPx, roundPx, paint);            paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));// 设置两张图片相交时的模式,参考http://trylovecatch.iteye.com/blog/1189452            canvas.drawBitmap(bitmap, src, dst, paint); // 以Mode.SRC_IN模式合并bitmap和已经draw了的Circle            return output;        }