#import "ViewController.h"

@interface ViewController ()

@property (nonatomic,strong)UIImageView *imageView;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake(, , , )];

    [self.view addSubview:self.imageView];

    [self yuan];

}

/**

 *  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 = ;

    //大圆形的宽度高度

    CGFloat ovalWH = imageWH +  * border;

    //1、开启位图上下文

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

    //2、画大圆

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

    //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(, , 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(, )];

    //4.从上下文中获取图片

    UIImage *clipImage = UIGraphicsGetImageFromCurrentImageContext();

    //5.关闭上下文

    UIGraphicsEndImageContext();

    _imageView.image = clipImage;

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

@end