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

不，UIImagePickerController 不能明确地做到这一点。

如果要根据图片的内容来判断。这是一个难题。如何在不了解图像内容的情况下确定图像的方向？

我可以建议您检查返回图像的宽度和长度，看看它是纵向还是横向。为了旋转图像，外面有一些库和代码，但我没有尝试太多。你可以看看this blog

Answer 2

Vodkhang 的回答部分不正确 - 现代相机在拍摄照片时会将明确的方向放入图像中。这已经很常见了大约 5 年多。

我之前使用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 camera preview is portrait in landscape app

Answer 3

    // 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。