Flip CIImage Horizontal

Question

I am trying to flip my CIImage Horizontal with :

image = [image imageByApplyingTransform:CGAffineTransformMakeScale(1, -1)];
image = [image imageByApplyingTransform:CGAffineTransformMakeTranslation(0, sourceExtent.size.height)];

But i always get the image flip vertical instead

why don't you try this UIImage* flippedImage = [UIImage imageWithCGImage:imgV.image.CGImage scale:imgV.image.scale orientation:UIImageOrientationUpMirrored]; — Teja Nandamuri, May 01 '16 at 15:20

score 10 · Accepted Answer · answered May 01 '16 at 13:12

10

Try this way:

image = [image imageByApplyingTransform:CGAffineTransformMakeScale(-1, 1)];
image = [image imageByApplyingTransform:CGAffineTransformMakeTranslation(0, sourceExtent.size.height)];

answered May 01 '16 at 13:12

Alex Kosyakov

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You meant to the second line to be: image = [image imageByApplyingTransform:CGAffineTransformMakeTranslation(sourceExtent.size.width,0)]; – Ken Aspeslagh May 09 '22 at 20:03

score 7 · Answer 2 · answered Jan 02 '18 at 22:05

7

This will properly flip the image horizontally and maintain proper coordinates.

In Obj-C:

image = [image imageByApplyingCGOrientation: kCGImagePropertyOrientationUpMirrored];

In Swift:

image = image.oriented(.upMirrored)

https://developer.apple.com/documentation/coreimage/ciimage/2919727-oriented

If what you want is to orient it in such a way that you can use it in an UIImage, then you want to flip it in both axes.

image = image.oriented(.downMirrored)

answered Jan 02 '18 at 22:05

Luis

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I get the error message "'oriented' is only available on iOS 11.0 or newer" – Chewie The Chorkie Feb 12 '18 at 19:10
image.oriented(.upMirrored) only works for iOS 11+, how can I implement it under iOS 11? – allenlinli Jun 17 '20 at 07:37

score 2 · Answer 3 · answered Oct 13 '16 at 16:25

2

Alex almost had it, but you need to adjust the translation as well:

image = [image imageByApplyingTransform:CGAffineTransformMakeScale(-1, 1)];
image = [image imageByApplyingTransform:CGAffineTransformMakeTranslation(sourceExtent.size.width, 0)];

answered Oct 13 '16 at 16:25

Kai Schaller

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score 1 · Answer 4 · answered May 08 '19 at 06:03

1

This what worked for me:

UIImage(ciImage: ciImage.oriented(.upMirrored).oriented(.left))

answered May 08 '19 at 06:03

Rotem

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Albert Renshaw · Answer 5 · 2022-10-04T00:05:53.057

This will allow you to flip a UIImage (or CIImage) in either horizontal or vertical directions:

UIImage *image;
BOOL mirrorX, mirrorY;


CIImage *ciimage = [CIImage imageWithCGImage:image.CGImage];
ciimage = [ciimage imageByApplyingTransform:CGAffineTransformMakeScale(mirrorX?-1:1, mirrorY?-1:1)];
ciimage = [ciimage imageByApplyingTransform:CGAffineTransformMakeTranslation(mirrorX?image.size.width:0, mirrorY?image.size.height:0)];
image = [UIImage imageWithCIImage:ciimage];

Flip CIImage Horizontal

5 Answers5