平常我们使用的圆角都是使用：
_imgIcon=[[UIImageView alloc] initWithFrame:CGRectMake(KScreenWidth-20-10-43, 18, 42, 42)];
_imgIcon.layer.cornerRadius=21.0;
// _imgIcon.image=[UIImage imageNamed:@"默认头像"];
_imgIcon.clipsToBounds=YES;
[btnIcon addSubview:_imgIcon];
过多的使用可能会造成GPU性能的损耗。
于是我继续查资料，发现图片的圆角可以将图片进行进行重绘，得到一张新的图片。方法如下：borderW这个主要设置头像的边框宽度
-(UIImage *)imageWithBorder:(CGFloat)borderW color:(UIColor *)borderColor image:(UIImage *)image{
//0.加载图片
// UIImage *image=[UIImage imageNamed:@"阿狸头像"];
//1.确定边框宽度
// CGFloat borderW=10;
//2.开启一个上下文
CGSize size =CGSizeMake(image.size.width + 2*borderW, image.size.height + 2*borderW);
UIGraphicsBeginImageContextWithOptions(size, NO, 0);
//3.绘制大圆。显示出来
UIBezierPath *path=[UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, size.width, size.height)];
[borderColor set];
[path fill];
//4.绘制一个小圆,显示出来
UIBezierPath *clipPath=[UIBezierPath bezierPathWithOvalInRect:CGRectMake(borderW, borderW, image.size.width, image.size.height)];
[clipPath addClip];
//5.把图片绘制到上下文当中
[image drawAtPoint:CGPointMake(borderW, borderW)];
//6.从上下文当中取出图片
UIImage *newImage=UIGraphicsGetImageFromCurrentImageContext();
//7.关闭上下文
UIGraphicsEndImageContext();
return newImage;
}
然后调用的时候：
self.imageV.image=[UIImage imageWithBorder:10.0 color:[UIColor greenColor] image:[UIImage imageNamed:@"阿狸头像"]];
WechatIMG1.jpeg
