UIImageView 在相机胶卷设置后设置图像方向

Question

将图像从相机胶卷设置为 UIImage 后图像方向发生变化。

UIImagePickerController *controller = [[UIImagePickerController alloc] init];
controller.sourceType = UIImagePickerControllerSourceTypeCamera;
controller.allowsEditing = NO;
controller.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType: UIImagePickerControllerSourceTypeCamera];
controller.delegate = self;
[self.navigationController presentViewController: controller animated: YES completion: nil];


- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

    [self.navigationController dismissViewControllerAnimated: YES completion: nil];
    UIImage *image = [info valueForKey: UIImagePickerControllerOriginalImage];
    NSData *imageData = UIImageJPEGRepresentation(image, 0.1);
    headerCell.userProfileImageView.image = [UIImage imageWithData:imageData];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsPath = [paths objectAtIndex:0]; //Get the docs directory
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"profileImage.png"]; //Add the file name
    NSData *pngData = UIImagePNGRepresentation(image);
    [pngData writeToFile:filePath atomically:YES];
}

相机胶卷的设置方向错误但照片库的设置完美。

任何人都遇到过类似的问题，请告诉我们您的意见以解决此问题。

Answer 1

来自线程 here 和下面的回答（来自 Dilip Rajkumar）：

您可以使用以下方法在选取图像后管理图像方向：（根据您的要求修改方法）

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

    [self.navigationController dismissViewControllerAnimated: YES completion: nil];

    UIImage *image = [self scaleAndRotateImage: [info objectForKey:UIImagePickerControllerOriginalImage]];

    NSData *imageData = UIImageJPEGRepresentation(image, 0.1);
    headerCell.userProfileImageView.image = [UIImage imageWithData:imageData];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsPath = [paths objectAtIndex:0]; //Get the docs directory
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"profileImage.png"]; //Add the file name
    NSData *pngData = UIImagePNGRepresentation(image);
    [pngData writeToFile:filePath atomically:YES];
}

- (UIImage *)scaleAndRotateImage:(UIImage *) image {
    int kMaxResolution = 320;

    CGImageRef imgRef = image.CGImage;

    CGFloat width = CGImageGetWidth(imgRef);
    CGFloat height = CGImageGetHeight(imgRef);


    CGAffineTransform transform = CGAffineTransformIdentity;
    CGRect bounds = CGRectMake(0, 0, width, height);
    if (width > kMaxResolution || height > kMaxResolution) {
        CGFloat ratio = width/height;
        if (ratio > 1) {
            bounds.size.width = kMaxResolution;
            bounds.size.height = bounds.size.width / ratio;
        }
        else {
            bounds.size.height = kMaxResolution;
            bounds.size.width = bounds.size.height * ratio;
        }
    }

    CGFloat scaleRatio = bounds.size.width / width;
    CGSize imageSize = CGSizeMake(CGImageGetWidth(imgRef), CGImageGetHeight(imgRef));
    CGFloat boundHeight;
    UIImageOrientation orient = image.imageOrientation;
    switch(orient) {

        case UIImageOrientationUp: //EXIF = 1
            transform = CGAffineTransformIdentity;
            break;

        case UIImageOrientationUpMirrored: //EXIF = 2
            transform = CGAffineTransformMakeTranslation(imageSize.width, 0.0);
            transform = CGAffineTransformScale(transform, -1.0, 1.0);
            break;

        case UIImageOrientationDown: //EXIF = 3
            transform = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;

        case UIImageOrientationDownMirrored: //EXIF = 4
            transform = CGAffineTransformMakeTranslation(0.0, imageSize.height);
            transform = CGAffineTransformScale(transform, 1.0, -1.0);
            break;

        case UIImageOrientationLeftMirrored: //EXIF = 5
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeTranslation(imageSize.height, imageSize.width);
            transform = CGAffineTransformScale(transform, -1.0, 1.0);
            transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
            break;

        case UIImageOrientationLeft: //EXIF = 6
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeTranslation(0.0, imageSize.width);
            transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
            break;

        case UIImageOrientationRightMirrored: //EXIF = 7
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeScale(-1.0, 1.0);
            transform = CGAffineTransformRotate(transform, M_PI / 2.0);
            break;

        case UIImageOrientationRight: //EXIF = 8
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeTranslation(imageSize.height, 0.0);
            transform = CGAffineTransformRotate(transform, M_PI / 2.0);
            break;

        default:
            [NSException raise:NSInternalInconsistencyException format:@"Invalid image orientation"];

    }

    UIGraphicsBeginImageContext(bounds.size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    if (orient == UIImageOrientationRight || orient == UIImageOrientationLeft) {
        CGContextScaleCTM(context, -scaleRatio, scaleRatio);
        CGContextTranslateCTM(context, -height, 0);
    }
    else {
        CGContextScaleCTM(context, scaleRatio, -scaleRatio);
        CGContextTranslateCTM(context, 0, -height);
    }

    CGContextConcatCTM(context, transform);

    CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, width, height), imgRef);
    UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return imageCopy;
}

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