把图片剪切为圆形

获取到的bitmap剪切为圆形


private Bitmap createCircleBitmap(Bitmap resource)
    {
        //获取图片的宽度
        int width = resource.getWidth();
        Paint paint = new Paint();
        //设置抗锯齿
        paint.setAntiAlias(true);

        //创建一个与原bitmap一样宽度的正方形bitmap
        Bitmap circleBitmap = Bitmap.createBitmap(width, width, Bitmap.Config.ARGB_8888);
        //以该bitmap为低创建一块画布
        Canvas canvas = new Canvas(circleBitmap);
        //以（width/2, width/2）为圆心，width/2为半径画一个圆
        canvas.drawCircle(width/2, width/2, width/2, paint);

        //设置画笔为取交集模式
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        //裁剪图片
        canvas.drawBitmap(resource, 0, 0, paint);

        return circleBitmap;
    }