UIImagePickerController 图像方向

Question

谁能告诉我如何使用 UIImagePickerController （相机和相册）委托确定图像的方向，相应地旋转并将其分配给 UIImageView？

Answer 1

沃德康的答案部分不正确——现代相机在拍照时会在图像中加入明确的方向。这种情况已经常见了大约 5 年多了。

我之前使用过此答案中的代码，通过直接从图片中读取“方向”信息来进行旋转：

UIImagePickerController 相机预览在横向应用程序中为纵向

Answer 2

    // Use this UIImagePickerController's  delegate method
    - (void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info {
        // Getting image user just has shoot
        UIImage* image = [info objectForKey:UIImagePickerControllerOriginalImage];

        // Fixing to stick with only one orientation (UIImageOrientationUp in this case)
        switch (image.imageOrientation) {
            case UIImageOrientationDown:
            case UIImageOrientationDownMirrored:
            case UIImageOrientationLeft:
            case UIImageOrientationLeftMirrored:
            case UIImageOrientationRight:
            case UIImageOrientationRightMirrored:
                image = [UIImage imageWithCGImage:image.CGImage
                                                  scale:image.scale
                                            orientation:UIImageOrientationUp]; // change this if you need another orientation
                break;
            case UIImageOrientationUp:
            case UIImageOrientationUpMirrored:
                // The image is already in correct orientation
                break;
        }

        // Do whatever you want with image (likely pass it to some UIImageView to display)
        UIImageView *imgView = [[UIImageView alloc] initWithImage:image];

        // Dismiss UIImagePickerController
        [picker dismissModalViewControllerAnimated:NO];
    }

注意：UIImageView 读取 imageOrientation 属性并相应地显示 UIImage。

Answer 3

不，UIImagePickerController 无法显式执行此操作。

如果你想根据图像的内容来确定。这是一个难题。在不了解图像内部内容的情况下，如何确定图像的方向？

我可以建议您一个技巧，检查返回图像的宽度和长度，看看它是纵向还是横向。对于旋转图像，外面有一些库和代码，但我没有尝试太多。你可以看看这个博客