//加载图片

    UIImage*image = [UIImageimageNamed:@"name"];

    //开启跟原始图片一样大的上下文

    UIGraphicsBeginImageContextWithOptions(image.size, NO, 0);

    //2、设置一个圆形裁剪区域

    //2.1绘制一个圆形

    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, image.size.width, image.size.height)];

    //2.2把圆形的路径设置在指定区域

    [pathaddClip];//超过裁剪区域以外的内容都给裁剪掉

    //3、把图片绘制到上下文当中

    [imagedrawAtPoint:CGPointZero];

    //4、从上下文当中取出图片

    UIImage *newImage =UIGraphicsGetImageFromCurrentImageContext();

    //5、关闭上下文

    UIGraphicsEndImageContext();

    //显示图片

    UIImageView*imageView= [[UIImageViewalloc]init];

    imageView.backgroundColor = [UIColor greenColor];

    imageView.frame=CGRectMake(100,300,100,100);

    imageView.image= newImage;

    [self.viewaddSubview:imageView];

//绘制带边框的图片裁剪

+(UIImage*)imageWithBorder:(CGFloat)borderW color:(UIColor*)color name:(UIImage*)image{

    //0、加载图片

    //1、确定边框宽度

    CGFloatborderWidth = borderW;

    //2、开启一个上下文

    CGSizesize =CGSizeMake(image.size.width+2*borderWidth, image.size.height+2*borderWidth);

    UIGraphicsBeginImageContextWithOptions(size, NO, 0);

    //3、绘制大圆显示出来

    UIBezierPath*path = [UIBezierPathbezierPathWithOvalInRect:CGRectMake(0,0, size.width, size.height)];

    [colorset];

    [pathfill];

    //4、绘制小圆,把小圆设置成裁剪区域

    UIBezierPath*smallPath =[UIBezierPathbezierPathWithOvalInRect:CGRectMake(borderWidth, borderWidth, image.size.width, image.size.height)];

    [smallPathaddClip];

    //5、把图片绘制到上下文当中

    [imagedrawAtPoint:CGPointMake(borderWidth, borderWidth)];

    //6、从上下文中取出图片

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    //7、关闭上下文

    UIGraphicsEndImageContext();

    returnnewImage;

}