iOS圆形图片裁剪，原型图片外面加一个圆环

/**

*  在圆形外面加一个圆环

*/

- (void)yuanHuan{

//0.加载图片

UIImage *image = [UIImage imageNamed:@"AppIcon1024"];

//图片的宽度

CGFloat imageWH = image.size.width;

//设置圆环的宽度

CGFloat border = 1;

//大圆形的宽度高度

CGFloat ovalWH = imageWH + 2 * border;

//1、开启位图上下文

UIGraphicsBeginImageContextWithOptions(CGSizeMake(ovalWH, ovalWH), NO, 0);

//2、画大圆

UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, ovalWH, ovalWH)];

[[UIColor redColor] set];

[path fill];

//3、设置裁剪区（小圆）

UIBezierPath *clipPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(border, border, imageWH, imageWH)];

[clipPath addClip];

//4、绘制图片

[image drawAtPoint:CGPointMake(border, border)];

//5、获取图片

UIImage *clipImage = UIGraphicsGetImageFromCurrentImageContext();

//6、关闭上下文

UIGraphicsEndImageContext();

self.imageView.image = clipImage;

}

/**

*  裁剪一个原型图片

*/

- (void)yuan{

//获取图片

UIImage *image = [UIImage imageNamed:@"AppIcon1024"];

//1.开启位图上下文，跟图片尺寸大小一样

//NO:不透明  0：scale不缩放

UIGraphicsBeginImageContextWithOptions(image.size, NO, 0);

//2.设置图形裁剪区域，正切图片

//2.1创建一个圆形路径

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

//2.2把路径设置裁剪区

[path addClip];

//3.绘制图片

[image drawAtPoint:CGPointMake(0, 0)];

//4.从上下文中获取图片

UIImage *clipImage = UIGraphicsGetImageFromCurrentImageContext();

//5.关闭上下文

UIGraphicsEndImageContext();

_imageView.image = clipImage;

}