设置圆角图片

设置圆形图片(建议放到分类中使用)

- (UIImage *)cutCircleImage {     
            UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0); 
            // 获取上下文 
            CGContextRef ctr = UIGraphicsGetCurrentContext(); 
            // 设置圆形
            CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height); 
            CGContextAddEllipseInRect(ctr, rect); 
            // 裁剪 
            CGContextClip(ctr); 
            // 将图片画上去 
            [self drawInRect:rect]; 
            UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); 
            UIGraphicsEndImageContext(); 
            return image;
}