1 //回调方法
 2 - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
 3 {
 4   // 第一步，将sampleBuffer转成UIImage
 5     UIImage *image = [self imageFromSampleBuffer:sampleBuffer];
 6     // 第二步，用Decoder识别图象
 7     [self decodeImage:image];
 8 }
 9
10 #pragma mark - 截取图片
11
12 - (void)cutMapView:(UIView *)theView
13
14 {
15
16 //************** 得到图片 *******************
17
18 CGRect rect = theView.frame; //截取图片大小
19
20
21
22 //开始取图，参数：截图图片大小
23
24 UIGraphicsBeginImageContext(rect.size);
25
26 //截图层放入上下文中
27
28 [theView.layer renderInContext:UIGraphicsGetCurrentContext()];
29
30 //从上下文中获得图片
31
32 UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
33
34 //结束截图
35
36 UIGraphicsEndImageContext();
37
38
39
40
41
42 //************** 存图片 *******************
43
44 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
45
46 NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:[NSStringstringWithFormat:@"%@.png",@"jietu"]]; // 保存文件的名称
47
48 NSLog(@"filePath = %@",filePath);
49
50 //UIImagePNGRepresentation方法将image对象转为NSData对象
51
52 //写入文件中
53
54 BOOL result = [UIImagePNGRepresentation(image)writeToFile: filePath atomically:YES];
55
56 NSLog(@"result = %d",result);
57
58
59
60
61
62 //*************** 截取小图 ******************
63
64 CGRect rect1 = CGRectMake(90, 0, 82, 82);//创建矩形框
65
66 //对图片进行截取
67
68 UIImage * image2 = [UIImage imageWithCGImage:CGImageCreateWithImageInRect([image CGImage], rect1)];
69
70 NSString *filePath2 = [[paths objectAtIndex:0] stringByAppendingPathComponent:[NSStringstringWithFormat:@"%@.png",@"jietu2"]]; // 保存文件的名称
71
72 NSLog(@"filePath = %@",filePath);
73
74 BOOL result2 = [UIImagePNGRepresentation(image2)writeToFile:filePath2 atomically:YES];
75
76 NSLog(@"result2 = %d",result2);
77
78
79
80 //存入相册
81
82 //UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);
83
84 }
85
86
87 //截取图片特定区域
88 /**
89 *从图片中按指定的位置大小截取图片的一部分
90 * UIImage image 原始的图片
91 * CGRect rect 要截取的区域
92 */
93 - (UIImage *)imageFromImage:(UIImage *)image inRect:(CGRect)rect {
94     CGImageRef sourceImageRef = [image CGImage];
95     CGImageRef newImageRef =     CGImageCreateWithImageInRect(sourceImageRef, rect);
96     UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
97     return newImage;
98 }