ImageMagick MagickAutoOrientImage

最近在用imageMagick 进行图像处理，主要是lua ffi调用ImageMagick， 发现MagickAutoOrientImage在旧版本中不存在，目前可以确定的是这个函数在ImageMagick 6.8.9中才出现。

1WandExport MagickBooleanType MagickAutoOrientImage(MagickWand *wand)
2{
3
4  Image
5    *orient_image;
6
7  assert(wand != (MagickWand *) NULL);
8  assert(wand->signature == WandSignature);
9  if (wand->debug != MagickFalse)
10    (void) LogMagickEvent(WandEvent,GetMagickModule(),"%s",wand->name);
11  if (wand->images == (Image *) NULL)
12    ThrowWandException(WandError,"ContainsNoImages",wand->name);
13  orient_image=AutoOrientImage(wand->images,wand->images->orientation,
14    wand->exception);
15  if (orient_image == (Image *) NULL)
16    return(MagickFalse);
17  ReplaceImageInList(&wand->images,orient_image);
18  return(MagickTrue);
19}

所以就要看AutoOrientImage的实现来手动实现

1MagickExport Image *AutoOrientImage(const Image *image,
2  const OrientationType orientation,ExceptionInfo *exception)
3{
4  Image
5    *orient_image;
6
7  assert(image != (const Image *) NULL);
8  assert(image->signature == MagickSignature);
9  assert(exception != (ExceptionInfo *) NULL);
10  assert(exception->signature == MagickSignature);
11  orient_image=(Image *) NULL;
12  switch(orientation)
13  {
14    case UndefinedOrientation:
15    case TopLeftOrientation:
16    default:
17    {
18      orient_image=CloneImage(image,0,0,MagickTrue,exception);
19      break;
20    }
21    case TopRightOrientation:
22    {
23      orient_image=FlopImage(image,exception);
24      break;
25    }
26    case BottomRightOrientation:
27    {
28      orient_image=RotateImage(image,180.0,exception);
29      break;
30    }
31    case BottomLeftOrientation:
32    {
33      orient_image=FlipImage(image,exception);
34      break;
35    }
36    case LeftTopOrientation:
37    {
38      orient_image=TransposeImage(image,exception);
39      break;
40    }
41    case RightTopOrientation:
42    {
43      orient_image=RotateImage(image,90.0,exception);
44      break;
45    }
46    case RightBottomOrientation:
47    {
48      orient_image=TransverseImage(image,exception);
49      break;
50    }
51    case LeftBottomOrientation:
52    {
53      orient_image=RotateImage(image,270.0,exception);
54      break;
55    }
56  }
57  if (orient_image != (Image *) NULL)
58    orient_image->orientation=TopLeftOrientation;
59  return(orient_image);
60}