CALayer

//取得layer
    CALayer *layer = self.purpleView.layer;
    // 绘制边框宽度
   layer.borderWidth = 50;
    // 绘制边框颜色
    layer.borderColor = [UIColor greenColor].CGColor;
    //绘制圆角
    layer.cornerRadius  = 10;
    //剪切
    //layer.masksToBounds = YES;打开之后阴影设置无效，在层上绘制的范围
    //绘制阴影
    layer.shadowColor = [UIColor blueColor].CGColor;
    layer.shadowOffset = CGSizeMake(10, 10);
    layer.shadowOpacity = 0.5;