下面的代码可以裁剪出圆形的图片，
1，先把不规则图片转成正方形图片
UIGraphicsBeginImageContext(newSize); [image drawInRect:CGRectMake(,,newSize.width,newSize.width)]; UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext();
2 ，把正方形图像绘制剪切为圆形
UIGraphicsBeginImageContext(image.size);
CGContextRef context = UIGraphicsGetCurrentContext(); CGRect rect = CGRectMake(, , image.size.width, image.size.height);
CGContextAddEllipseInRect(context, rect);
CGContextClip(context); //进行剪切，所有context绘制只保留能够被当前path进行fill的区域
[image drawInRect:rect]; //绘制原图 UIImage *newimg = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();