iOS UIImagePickerController result image orientation after upload

Question

I am testing my iPhone application on an iOS 3.1.3 iPhone. I am selecting/capturing an image using a UIImagePickerController:

UIImagePickerCont         


        

Answer 1

Here's UIImage extension for swift:

extension UIImage {

    func fixOrientation() -> UIImage {

        // No-op if the orientation is already correct
        if ( self.imageOrientation == UIImageOrientation.Up ) {
            return self;
        }

        // We need to calculate the proper transformation to make the image upright.
        // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
        var transform: CGAffineTransform = CGAffineTransformIdentity

        if ( self.imageOrientation == UIImageOrientation.Down || self.imageOrientation == UIImageOrientation.DownMirrored ) {
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height)
            transform = CGAffineTransformRotate(transform, CGFloat(M_PI))
        }

        if ( self.imageOrientation == UIImageOrientation.Left || self.imageOrientation == UIImageOrientation.LeftMirrored ) {
            transform = CGAffineTransformTranslate(transform, self.size.width, 0)
            transform = CGAffineTransformRotate(transform, CGFloat(M_PI_2))
        }

        if ( self.imageOrientation == UIImageOrientation.Right || self.imageOrientation == UIImageOrientation.RightMirrored ) {
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform,  CGFloat(-M_PI_2));
        }

        if ( self.imageOrientation == UIImageOrientation.UpMirrored || self.imageOrientation == UIImageOrientation.DownMirrored ) {
            transform = CGAffineTransformTranslate(transform, self.size.width, 0)
            transform = CGAffineTransformScale(transform, -1, 1)
        }

        if ( self.imageOrientation == UIImageOrientation.LeftMirrored || self.imageOrientation == UIImageOrientation.RightMirrored ) {
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
        }

        // Now we draw the underlying CGImage into a new context, applying the transform
        // calculated above.
        var ctx: CGContextRef = CGBitmapContextCreate(nil, Int(self.size.width), Int(self.size.height),
            CGImageGetBitsPerComponent(self.CGImage), 0,
            CGImageGetColorSpace(self.CGImage),
            CGImageGetBitmapInfo(self.CGImage));

        CGContextConcatCTM(ctx, transform)

        if ( self.imageOrientation == UIImageOrientation.Left ||
            self.imageOrientation == UIImageOrientation.LeftMirrored ||
            self.imageOrientation == UIImageOrientation.Right ||
            self.imageOrientation == UIImageOrientation.RightMirrored ) {
                CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage)
        } else {
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.CGImage)
        }

        // And now we just create a new UIImage from the drawing context and return it
        return UIImage(CGImage: CGBitmapContextCreateImage(ctx))!
    }
}

Based on MetalHeart2003's earlier work..

Answer 2

@an0, thanks for the answer!
The only thing is autoreleasepool: 

func fixOrientation(img: UIImage) -> UIImage? {

    let result: UIImage?
    if img.imageOrientation == .up {
        result = img
    } else {

        result = autoreleasepool { () -> UIImage? in
            UIGraphicsBeginImageContextWithOptions(img.size, false, img.scale)
            let rect = CGRect(x: 0, y: 0, width: img.size.width, height: img.size.height)
            img.draw(in: rect)

            let normalizedImage = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()

            return normalizedImage
        }
    }

    return result
}

Answer 3

I used this page when designing my app that takes pictures and I found that the following method will correct the orientation and use less memory and processor than previous answers:

CGImageRef cgRef = image.CGImage;
image = [[UIImage alloc] initWithCGImage:cgRef scale:1.0 orientation:UIImageOrientationUp];

This basically just rewraps the actual image data with a new orientation. I was using @an0's code but it makes a new image in memory which can be taxing on a 3264x2448 image that you might get from a camera.

Answer 4

Here’s a solution that doesn’t change the colorspace of the original image. If you want to normalize the orientation of a grayscale image, you are out of luck with all solutions based on UIGraphicsBeginImageContextWithOptions because it creates a context in the RGB colorspace. Instead, you have to create a context with the same properties as the original image and draw:

extension UIImage {
    static let rotatedOrentations: [UIImage.Orientation] = [.left, .leftMirrored, .right, .rightMirrored]

    func normalizedImage() -> UIImage {
        if imageOrientation == .up {
            return self
        }

        let image = self.cgImage!
        let swapOrientation = UIImage.rotatedOrentations.contains(imageOrientation)
        let width = swapOrientation ? image.height : image.width
        let height = swapOrientation ? image.width : image.height
        let context = CGContext(data: nil, width: width, height: height, bitsPerComponent: image.bitsPerComponent, bytesPerRow: image.bytesPerRow, space: image.colorSpace!, bitmapInfo: image.bitmapInfo.rawValue)!
        let flipVertical = CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: CGFloat(height));
        context.concatenate(flipVertical)
        UIGraphicsPushContext(context)
        self.draw(at: .zero)
        UIGraphicsPopContext()

        return UIImage(cgImage: context.makeImage()!)
    }
}

Answer 5

I figured out a much simpler one:

- (UIImage *)normalizedImage {
    if (self.imageOrientation == UIImageOrientationUp) return self; 

    UIGraphicsBeginImageContextWithOptions(self.size, NO, self.scale);
    [self drawInRect:(CGRect){0, 0, self.size}];
    UIImage *normalizedImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return normalizedImage;
}

BTW: @Anomie's code does not take scale into account, so will not work for 2x images.

Answer 6

Update for Swift 3.1 based on Sourabh Sharma's answer, with code clean up.

extension UIImage {
    func fixedOrientation() -> UIImage {
        if imageOrientation == .up { return self }

        var transform:CGAffineTransform = .identity
        switch imageOrientation {
        case .down, .downMirrored:
            transform = transform.translatedBy(x: size.width, y: size.height).rotated(by: .pi)
        case .left, .leftMirrored:
            transform = transform.translatedBy(x: size.width, y: 0).rotated(by: .pi/2)
        case .right, .rightMirrored:
            transform = transform.translatedBy(x: 0, y: size.height).rotated(by: -.pi/2)
        default: break
        }

        switch imageOrientation {
        case .upMirrored, .downMirrored:
            transform = transform.translatedBy(x: size.width, y: 0).scaledBy(x: -1, y: 1)
        case .leftMirrored, .rightMirrored:
            transform = transform.translatedBy(x: size.height, y: 0).scaledBy(x: -1, y: 1)
        default: break
        }

        let ctx = CGContext(data: nil, width: Int(size.width), height: Int(size.height),
                                       bitsPerComponent: cgImage!.bitsPerComponent, bytesPerRow: 0,
                                       space: cgImage!.colorSpace!, bitmapInfo: cgImage!.bitmapInfo.rawValue)!
        ctx.concatenate(transform)

        switch imageOrientation {
        case .left, .leftMirrored, .right, .rightMirrored:
            ctx.draw(cgImage!, in: CGRect(x: 0, y: 0, width: size.height,height: size.width))
        default:
            ctx.draw(cgImage!, in: CGRect(x: 0, y: 0, width: size.width,height: size.height))
        }
        return UIImage(cgImage: ctx.makeImage()!)
    }
}

Picker delegate method example:

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    guard let originalImage = info[UIImagePickerControllerOriginalImage] as? UIImage else { return }
    let fixedImage = originalImage.fixedOrientation()
    // do your work
}