####【iOS】图片裁剪
UIImage *imageTop=[UIImage imageNamed:@"1111.jpg"];
//根据创建的image 进行区域裁剪（关键代码）
CGImageRef refTopImg = CGImageCreateWithImageInRect(imageTop.CGImage, CGRectMake(0, 0, imageTop.size.width, imageTop.size.height/2));
_topImageView =[[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 375, 667/2)];
_topImageView.image =[UIImage imageWithCGImage:refTopImg];
[self.view addSubview:_topImageView];
[Demo地址](https://github.com/joealzhou/cutImage)
