如何知道照片是处于横向模式还是纵向模式？

Question

我从iPhone/iPad库中加载照片，其中大多数是在肖像模式下，我想知道如何在横向或肖像模式下检查照片？

Answer 1

使用UIImage实例的imageOrientation属性。它将返回一个these常量。

示例：

UIImage *image = //从库中加载

if (image.imageOrientation == UIImageOrientationUp) {
    NSLog(@"portrait");
} else if (image.imageOrientation == UIImageOrientationLeft || image.imageOrientation == UIImageOrientationRight) {
    NSLog(@"landscape");
}

Answer 2

我在运行iOS 5.0的iPhone 4上测试了这段代码的数十张实际图片，并成功地将它们都设置为纵向模式。这就是修复/检查的方法

if (image.imageOrientation == UIImageOrientationUp ||
        image.imageOrientation == UIImageOrientationDown )
    {
        NSLog(@"Image is in Landscape Fix it to portrait ....");

        backgroundView.frame = self.view.bounds;
        backgroundView.autoresizingMask=UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
        backgroundView.contentMode = UIViewContentModeScaleAspectFill;
    }
    else
    {
        NSLog(@"Image is in Portrait everything is fine ...");
    }

下面是做这个检查的一个愚蠢的方法

-(void)imagePickerController:(UIImagePickerController *)picker
      didFinishPickingImage : (UIImage *)image
                 editingInfo:(NSDictionary *)editingInfo
{

    // Get the data for the image
    NSData* imageData = UIImageJPEGRepresentation(image, 1.0);




    if ([UIImage imageWithData:imageData].size.width >  [UIImage imageWithData:imageData].size.height)
    {
        NSLog(@"Select Image is in Landscape Mode ....");

    }
    else
    {
        NSLog(@"Select Image is in Portrait Mode ...");

    }
}