裁剪带圆环的图片

Posted on 2016-07-04 19:17  柠檬片  阅读(128)  评论(0)    收藏  举报 
 1 //1.加载要裁剪的图片
 2     UIImage * image = [UIImage imageNamed:@"me"];
 3     
 4     //2.开启一个比图片稍大的图形上下文 (bitmap)
 5     
 6     CGFloat margin = 5;
 7     
 8     //2.1计算图形上下文的size
 9     CGSize ctxSize = CGSizeMake(image.size.width + 2 * margin, image.size.height + 2 * margin);
10     
11     UIGraphicsBeginImageContextWithOptions(ctxSize, NO, 0.0);
12     
13     //3.获取刚刚开启的图形上下文对象
14     CGContextRef ctx = UIGraphicsGetCurrentContext();
15     
16     
17     //-------------------画一个圆环--------------------
18     //4.创建一个圆环路径
19     //设置圆心
20     CGPoint centerP = CGPointMake(ctxSize.width/2, ctxSize.height/2);
21     
22     //设置半径
23     CGFloat radius = MIN(image.size.width, image.size.height)/2;
24     
25     UIBezierPath * path = [UIBezierPath bezierPathWithArcCenter:centerP radius:radius startAngle:0 endAngle:2*M_PI clockwise:YES];
26     //设置圆环的颜色和线宽
27     CGContextSetLineWidth(ctx, 5);
28     
29     [[UIColor redColor] set];
30     
31     CGContextAddPath(ctx, path.CGPath);
32     
33 //    //6.执行裁剪
34 //    CGContextClip(ctx);
35     
36     //4.1 渲染
37     CGContextStrokePath(ctx);
38     //-------------------画一个圆环--------------------
39     
40     
41     
42     //-------------------画一个裁剪区域--------------------
43     //5.创建裁剪的路径
44     UIBezierPath * path1 = [UIBezierPath bezierPathWithArcCenter:centerP radius:radius startAngle:0 endAngle:2*M_PI clockwise:YES];
45     
46     //5.1 把路径添加到图形上下文中
47     CGContextAddPath(ctx, path1.CGPath);
48     
49     //6.执行裁剪
50     CGContextClip(ctx);
51     
52     
53     //-------------------画一个裁剪区域--------------------
54     
55     
56     
57     
58     
59     
60     //7.绘制图片
61     [image drawAtPoint:CGPointMake(margin, margin)];
62     
63     //8.获取图片
64     UIImage * getImage = UIGraphicsGetImageFromCurrentImageContext();
65     
66     //8.1 结束图形上下文
67     UIGraphicsEndImageContext();
68     
69     //9.保存
70     self.imageView.image = getImage;
71     
72     UIImageWriteToSavedPhotosAlbum(getImage, nil, nil, nil);
73     
74     //9.1 保存沙盒
75     
76     NSString * documents = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
77     
78     NSString * fileName = [documents stringByAppendingPathComponent:@"002.png"];
79     
80     NSData * imageData = UIImagePNGRepresentation(getImage);
81     
82     [imageData writeToFile:fileName atomically:YES];
裁剪带圆环的图片