iPhone，如何检测拍摄的图片方向？

Question

有没有办法检测手机拍照时的方向？

我在UIView中使用UIImageView，并使用UIImagePicker拍摄或从相机胶卷中选择照片。但如果图片是横向拍摄的，我想检测到这一点并调整图像视图的大小，以防止图像被拉伸和看起来很愚蠢。

有人知道是否可能实现这一点（我认为是可能的，因为照片应用程序可以做到这一点），如果可能，我该如何在代码/界面构建器设置中进行操作？

- Mark McGookin

Answer 1

您可以使用myImage.imageOrientation，它将给您UIImageOrientation，或者如果出于某种原因您想要直接在“imagePickerController:didFinishPickingMediaWithInfo:”方法中获得EXIF信息，可以通过访问信息字典[info objectForKey:@"Orientation"]来实现；请注意：这与UIImageOrientation直接相关，关联如下：

- (UIImageOrientation)orientationFromEXIF:(int)exif
{  
    UIImageOrientation newOrientation;  
    switch (exif)
    {  
    case 1:  
        newOrientation = UIImageOrientationUp;  
        break;  
    case 3:  
        newOrientation = UIImageOrientationDown;  
        break;  
    case 8:  
        newOrientation = UIImageOrientationLeft;  
        break;  
    case 6:  
        newOrientation = UIImageOrientationRight;  
        break;  
    case 2:  
        newOrientation = UIImageOrientationUpMirrored;  
        break;  
    case 4:  
        newOrientation = UIImageOrientationDownMirrored;  
        break;  
    case 5:  
        newOrientation = UIImageOrientationLeftMirrored;  
        break;  
    case 7:  
        newOrientation = UIImageOrientationRightMirrored;  
        break;  
    }  
    return newOrientation;  
}

但最好使用.imageOrientation。

- averydev

---

每当我尝试访问imageOrientation时，XCode总是会给出“bad access（坏地址）”错误。 - zakdances

Answer 2

请查看以下 Swift 代码 -

class func DetectOrientation(img : UIImage) -> UIImageOrientation{
            var newOrientation = UIImageOrientation.Up
            switch (img.imageOrientation)
            {
            case .Up:
                newOrientation = UIImageOrientation.Up;
                break;
            case .Down:
                newOrientation = UIImageOrientation.Down;
                break;
            case .Left:
                newOrientation = UIImageOrientation.Left;
                break;
            case .Right:
                newOrientation = UIImageOrientation.Right;
                break;
            case .UpMirrored:
                newOrientation = UIImageOrientation.UpMirrored;
                break;
            case .DownMirrored:
                newOrientation = UIImageOrientation.DownMirrored;
                break;
            case .LeftMirrored:
                newOrientation = UIImageOrientation.LeftMirrored;
                break;
            case .RightMirrored:
                newOrientation = UIImageOrientation.RightMirrored;
                break;
            }
            return newOrientation;
        }

- pankaj kshatriya

Answer 3

查看UIImage中的@property(nonatomic, readonly) UIImageOrientation imageOrientation。

- David Neiss