#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

}

-  (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event

{

//    获取要剪裁的图片

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

//    给图片设置的rect

    CGRect imageRect = CGRectMake(, , image.size.width, image.size.height);

//    开启图形上下文

    UIGraphicsBeginImageContextWithOptions(image.size, NO, 0.0);

//    获取图形上下文

    CGContextRef bitmapContext = UIGraphicsGetCurrentContext();

//    画圆的路径

    CGContextAddEllipseInRect(bitmapContext, imageRect);

//     把圆路径之外的剪切掉

    CGContextClip(bitmapContext);

//    在上下文中添加图片

    [image drawInRect:imageRect];

//    给图片设置边框

    //给边框设置宽度

    CGContextSetLineWidth(bitmapContext, );

    //给边框设置颜色

    [[UIColor blueColor] set];

    CGContextAddEllipseInRect(bitmapContext, imageRect);

//    画出该边框

    CGContextStrokePath(bitmapContext);

    //    获取这个图片

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

//    结束位图编辑

    UIGraphicsEndImageContext();

//    显示图片

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

    [self.view addSubview:imageView];

    imageView.image = newImage;

//    保存图片

//    先把图片转存NSData,调用write方法

    NSData *imageData = UIImagePNGRepresentation(newImage);

    [imageData writeToFile:@"/Users/mac/Desktop/new.png" atomically:YES];

}