开发中遇到问题搜索的结果，来自他人，不做其他用途，未能注明来源，如有侵权联系本人删除。
给UIImage添加生成圆角图片的扩展API：这是on-screen-rendering
- (UIImage *)imageWithCornerRadius:(CGFloat)radius {
CGRect rect = (CGRect){0.f, 0.f, self.size};
UIGraphicsBeginImageContextWithOptions(self.size,NO,UIScreen.mainScreen.scale);
CGContextAddPath(UIGraphicsGetCurrentContext(), [UIBezierPathbezierPathWithRoundedRect:rect cornerRadius:radius].CGPath);
CGContextClip(UIGraphicsGetCurrentContext());
[selfdrawInRect:rect];
UIImage*image =UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
returnimage;
