Images with unusual color spaces not correctly loaded by Core Image

Question

Created Apr ’25

Replies 2

Boosts 3

Participants 2

Some users reported that their images are not loading correctly in our app. After a lot of debugging we identified the following:

This only happens when the app is build for Mac Catalyst. Not on iOS, iPadOS, or “real” macOS (AppKit).
The images in question have unusual color spaces. We observed the issue for uRGB and eciRGB v2.
Those images are rendered correctly in Photos and Preview on all platforms.
When displaying the image inside of a UIImageView or in a SwiftUI Image, they render correctly.
The issue only occurs when loading the image via Core Image.
When comparing the different Core Image render graphs between AppKit (working) and Catalyst (faulty) builds, they look identical—except for the result.

Mac (AppKit):

macOS

Catalyst:

Catalyst

Something seems to be off when Core Image tries to load an image with foreign color space in Catalyst.

We identified a workaround: By using a CGImageDestination to transcode the image using the kCGImageDestinationOptimizeColorForSharing option, Image I/O will convert the image to sRGB (or similar) and Core Image is able to load the image correctly. However, one potentially loses fidelity this way.

Or might there be a better workaround?

Boost

Answer 1

FrankSchlegel OP

Apr ’25

Also filed as FB17081255, including a sample project.

Thanks for looking into this!

0

Answer 2

Enie OP

1w

We have been postponing the release of our app since end of last year now because I could not find a solution or even the reason for the wrong colors in an eciRGB v2 image.

There are some differences though. We also use Core Image to load that color space, when I debug the CI image it got really dark. For us this problem occurs on macOS using AppKit. It appears rather sporadically even with exactly the same image which makes it really hard to debug.

Now that I see that CoreImage might be faulty I will try to exchange it with ImageI/O. The filters that I use I am sure can be written in Metal just as well.

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