从相机胶卷设置后，UIImageView设置图像取向

Question

将图像方向从相机胶卷设置为UIImage后，图像方向会发生变化。

function addUser(e){
        id = $('#emailAccount').val();

        var name = $('#nameClient').val();      
        var email = $('#emailAccount').val();
        var psword = $('#passwordAccount').val();

        if (name == ""){
            alert("Field name cannot be empty.");   
            e.preventDefault();
        }else if (email == ""){
            alert("Field email cannot be empty.");
            e.preventDefault();
        }else if (psword == ""){
            alert("Field password cannot be empty.")
            e.preventDefault();
        }else {
            users = JSON.parse(localStorage.getItem("users"));

            //Check users

            if(users == null){
                users = [];         
            }
            var userList = JSON.parse(localStorage.getItem("users"));

            //new User object

            var new_user = {
                "id":id,
                "Name": name,               
                "Email": email,
                "Parola": psword                
            }

            users.push(new_user);
            localStorage.setItem('users', JSON.stringify(users));

            console.log("User added")
        }

    }

});

从相机滚动设置方向错误，但从照片库完全设置。

任何人都有这样的相同问题，请告诉我们您的意见以解决此问题。

Answer 1

来自主题here及以下回答（由Dilip Rajkumar撰写）：

https://stackoverflow.com/a/10602363/5575752

选择图片后，您可以使用以下方法管理图像方向： （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;
}