Extension to fix orientation of an UIImage (Sets orientation to portrait)

UIImageFixedOrientationExtension.swift

extension UIImage {

    func fixedOrientation() -> UIImage {
        
        if imageOrientation == UIImageOrientation.Up {
            return self
        }
        
        var transform: CGAffineTransform = CGAffineTransformIdentity
        
        switch imageOrientation {
        case UIImageOrientation.Down, UIImageOrientation.DownMirrored:
            transform = CGAffineTransformTranslate(transform, size.width, size.height)
            transform = CGAffineTransformRotate(transform, CGFloat(M_PI))
            break
        case UIImageOrientation.Left, UIImageOrientation.LeftMirrored:
            transform = CGAffineTransformTranslate(transform, size.width, 0)
            transform = CGAffineTransformRotate(transform, CGFloat(M_PI_2))
            break
        case UIImageOrientation.Right, UIImageOrientation.RightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, size.height)
            transform = CGAffineTransformRotate(transform, CGFloat(-M_PI_2))
            break
        case UIImageOrientation.Up, UIImageOrientation.UpMirrored:
            break
        }
        
        switch imageOrientation {
        case UIImageOrientation.UpMirrored, UIImageOrientation.DownMirrored:
            CGAffineTransformTranslate(transform, size.width, 0)
            CGAffineTransformScale(transform, -1, 1)
            break
        case UIImageOrientation.LeftMirrored, UIImageOrientation.RightMirrored:
            CGAffineTransformTranslate(transform, size.height, 0)
            CGAffineTransformScale(transform, -1, 1)
        case UIImageOrientation.Up, UIImageOrientation.Down, UIImageOrientation.Left, UIImageOrientation.Right:
            break
        }
        
        let ctx: CGContextRef = CGBitmapContextCreate(nil, Int(size.width), Int(size.height), CGImageGetBitsPerComponent(CGImage), 0, CGImageGetColorSpace(CGImage), CGImageAlphaInfo.PremultipliedLast.rawValue)!
        
        CGContextConcatCTM(ctx, transform)
        
        switch imageOrientation {
        case UIImageOrientation.Left, UIImageOrientation.LeftMirrored, UIImageOrientation.Right, UIImageOrientation.RightMirrored:
            CGContextDrawImage(ctx, CGRectMake(0, 0, size.height, size.width), CGImage)
            break
        default:
            CGContextDrawImage(ctx, CGRectMake(0, 0, size.width, size.height), CGImage)
            break
        }
        
        let cgImage: CGImageRef = CGBitmapContextCreateImage(ctx)!
        
        return UIImage(CGImage: cgImage)
    }
}

Its saved my time! Thanks all !!!

Amazing. Great work buds.

Could someone explain me why we need transform.translatedBy?

Wouldn't only .rotated(by... and .scaledBy(... (for flipped images) do it? 🤔

I believe those transform around the origin (0, 0) and would thus flip/rotate your image to be outside the box. if you try it with an angle of around 45° you’ll see how it would break.

I believe those transform around the origin (0, 0) and would thus flip/rotate your image to be outside the box. if you try it with an angle of around 45° you’ll see how it would break.

Thanks!