ios实现图片圆角方式小计

1. 最简单的方式就是要美工妹子给你给你切一张带圆角的图片，用iimageNamed:@""加载图片。
2. 通过图层layer实现，不过如果是tableView上面多处用到了图片圆角 使用layer会造成离屏渲染,会加大GPU的开销,在性能上会大大折扣，不建议使用。

self.imageView.layer.masksToBounds = yes;
self.imageView.layer.cornerRadius = 10;

3. 通过QuartzCore实现：

-(UIImage*) circleImage:(UIImage*) image withParam:(CGFloat) inset {
        UIGraphicsBeginImageContext(image.size);
        CGContextRef context = UIGraphicsGetCurrentContext();
        CGContextSetLineWidth(context, 2);
        CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
        CGRect rect = CGRectMake(inset, inset, image.size.width - inset * 2.0f,   image.size.height - inset * 2.0f);
        CGContextAddEllipseInRect(context, rect);
        CGContextClip(context);
        [image drawInRect:rect];
        CGContextAddEllipseInRect(context, rect);
        CGContextStrokePath(context);
        UIImage *newimg = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return newimg;
    }

4. 利用贝塞尔曲线画出来

self.imgView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 40, 40)];
    UIImage *image =[UIImage imageNamed:@"headerImage"];
    UIGraphicsBeginImageContextWithOptions(self.imgView.bounds.size, NO, 1.0);
    [[UIBezierPath bezierPathWithRoundedRect:self.imgView.bounds cornerRadius:self.imgView.bounds.size.width/2.0]addClip];
    [image drawInRect:self.imgView.bounds];
    self.imgView.image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();