IOS 同时设置 圆角阴影

项目提到一个新需求，把UIImageView切成圆角图标的同时，加上阴影。如下图：

实现方式：

// 头像
    UIImageView* head = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, headRadius * 2, headRadius * 2)];
    // 圆角图片
    [head sd_setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@", appImgUrl]] placeholderImage:[UIImage imageNamed:@"xjp.png"]];
    //设置边框的宽度
    head.layer.borderWidth = 1;
    //设置边框颜色
    head.layer.borderColor = [[UIColor colorWithRed:0.5 green:0.5 blue:0.5 alpha:0.5]CGColor];
    head.layer.masksToBounds = YES;
    head.layer.cornerRadius = headRadius;
 UIView *shadowView = [[UIView alloc]initWithFrame:CGRectMake(self.view.frame.size.width / 2 - headRadius, height, headRadius * 2, headRadius * 2)];
    shadowView.layer.shadowColor = [UIColor blackColor].CGColor;
    shadowView.layer.shadowOffset = CGSizeMake(0, 0);
    shadowView.layer.shadowOpacity = 1;
    shadowView.layer.shadowRadius = 5.0;
    shadowView.layer.cornerRadius = 5.0;
    shadowView.clipsToBounds = NO;
    [shadowView addSubview:head];
    [content addSubview:shadowView];

clipsToBounds
是指视图上的子视图,如果超出父视图的部分就截取掉,
masksToBounds
却是指视图的图层上的子图层,如果超出父图层的部分就截取掉