/**

     * 转换图片成圆形

     *

     * @param bitmap

     *            传入Bitmap对象

     * @return

     */

    public static 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;

            top = 0;

            bottom = width;

            left = 0;

            right = 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 int color = 0xff424242;

        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);

        canvas.drawARGB(0, 0, 0, 0);

        paint.setColor(color);

        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);

        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));

        canvas.drawBitmap(bitmap, src, dst, paint);

        return output;

    }

    /**

     * to圆角Bitmap

     * @param bitmap

     * @return

     */

    public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx) {

        try {

            Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),

                    bitmap.getHeight(), Config.ARGB_8888);

            Canvas canvas = new Canvas(output);

            final int color = 0xff424242;// 颜色值（0xff---alpha）

            final Paint paint = new Paint();

            final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());

            final RectF rectF = new RectF(rect);// Rect是使用int类型作为数值，RectF是使用float类型作为数值

            // --------抗锯齿-------//

            paint.setAntiAlias(true);

            canvas.drawARGB(0, 0, 0, 0);

            paint.setColor(color);

            canvas.drawRoundRect(rectF, roundPx, roundPx, paint);

            paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));

            final Rect src = new Rect(0, 0, bitmap.getWidth(),

                    bitmap.getHeight());

            canvas.drawBitmap(bitmap, null, rect, paint);

            return output;

        } catch (Exception e) {

            e.printStackTrace();

            return null;

        }

    }