相册里的照片是有方向，再根据图片的方向，再反回来就好了！

相册里的照片是有方向，再根据图片的方向，再反回来就好了！

1. + (void)fixOrientation:(UIImage *)aImage {
   
2.     if (aImage==nil || !aImage) {
   
3.         return;
   
4.     }
   
5.     // No-op if the orientation is already correct
   
6.     if (aImage.imageOrientation == UIImageOrientationUp) return;
   
7.    
   
8.     // We need to calculate the proper transformation to make the image upright.
   
9.     // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
   
10.     CGAffineTransform transform = CGAffineTransformIdentity;
    
11.     UIImageOrientation orientation=aImage.imageOrientation;
    
12.     int orientation_=orientation;
    
13.     switch (orientation_) {
    
14.         case UIImageOrientationDown:
    
15.         case UIImageOrientationDownMirrored:
    
16.             transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);
    
17.             transform = CGAffineTransformRotate(transform, M_PI);
    
18.             break;
    
19.            
    
20.         case UIImageOrientationLeft:
    
21.         case UIImageOrientationLeftMirrored:
    
22.             transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
    
23.             transform = CGAffineTransformRotate(transform, M_PI_2);
    
24.             break;
    
25.            
    
26.         case UIImageOrientationRight:
    
27.         case UIImageOrientationRightMirrored:
    
28.             transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);
    
29.             transform = CGAffineTransformRotate(transform, -M_PI_2);
    
30.             break;
    
31.     }
    
32.    
    
33.     switch (orientation_) {
    
34.         case UIImageOrientationUpMirrored:{
    
35.        
    
36.         }
    
37.         case UIImageOrientationDownMirrored:
    
38.             transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
    
39.             transform = CGAffineTransformScale(transform, -1, 1);
    
40.             break;
    
41.            
    
42.         case UIImageOrientationLeftMirrored:
    
43.         case UIImageOrientationRightMirrored:
    
44.             transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);
    
45.             transform = CGAffineTransformScale(transform, -1, 1);
    
46.             break;
    
47.     }
    
48.    
    
49.     // Now we draw the underlying CGImage into a new context, applying the transform
    
50.     // calculated above.
    
51.     CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,
    
52.                                              CGImageGetBitsPerComponent(aImage.CGImage), 0,
    
53.                                              CGImageGetColorSpace(aImage.CGImage),
    
54.                                              CGImageGetBitmapInfo(aImage.CGImage));
    
55.     CGContextConcatCTM(ctx, transform);
    
56.     switch (aImage.imageOrientation) {
    
57.         case UIImageOrientationLeft:
    
58.         case UIImageOrientationLeftMirrored:
    
59.         case UIImageOrientationRight:
    
60.         case UIImageOrientationRightMirrored:
    
61.             // Grr...
    
62.             CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);
    
63.             break;
    
64.            
    
65.         default:
    
66.             CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);
    
67.             break;
    
68.     }
    
69.    
    
70.     // And now we just create a new UIImage from the drawing context
    
71.     CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    
72.     UIImage *img = [UIImage imageWithCGImage:cgimg];
    
73.     CGContextRelease(ctx);
    
74.     CGImageRelease(cgimg);
    
75.     aImage=img;
    
76.     img=nil;
    
77. }