JPEG XL: Another multi-page improvement
Hi, sorry for the long hiatus.. This MR proposed to update and fix some of the twist and kinks to our JPEG XL multi-page capabilities.
Export dialog update
Replace image mode checkboxes into a clearer radio selections with short tooltip descriptions on hover. This will hopefully make the image mode choices much clearer. While I'm at it, I also reset the UI default tab index to 0 so that the first tab is shown when exporting to JPEG XL (it was thrown to third tab (advanced) before when exporting, seems like a minor regression?).
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Note: The old one is from 5.2.9 where the lossless alpha option !2077 (merged) didn't exist yet.
Better import workflow for multi-page image
On prior MR !2263 (merged) , multi-page JPEG XL images will be imported as an animation frames. This MR changed that so that it will be properly imported as a layers instead.
Add multi-page image import unit test
Adding a simple unit test to verify multi-page images are imported properly.
Limitations
This however still didn't fully cover some other image modes that JPEG XL can provide, for example:
- Multi-page animation: Image with multiple animations separated by page markers. In Krita, this image will be imported as a whole animation without separation.
- Multi-layered animation: Animated image with multiple layers per animation frame. In Krita, this image will be imported as an animation where the layers are flattened / coalesced.
Lately, I've spent quite a bit of time exploring those modes and what libjxl can do currently. But some of them are rather complex to implement here yet... Therefore I put them into a separate personal project to test them: https://github.com/kampidh/JXL-Frame-Stitcher
Test Plan
- Build Krita
- Try to export some documents to JPEG XL image with different modes shown on the export UI (flattened, animated, multi-layered, and multi-paged)
- Verify the resulting images are correctly saved
- Verify multi-paged images are correctly imported on Krita
Formalities Checklist
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I confirmed this builds. -
I confirmed Krita ran and the relevant functions work. -
I tested the relevant unit tests and can confirm they are not broken. (If not possible, don't hesitate to ask for help!) -
I made sure my commits build individually and have good descriptions as per KDE guidelines. -
I made sure my code conforms to the standards set in the HACKING file. -
I can confirm the code is licensed and attributed appropriately, and that unattributed code is mine, as per KDE Licensing Policy. -
Does the patch add a user-visible feature? If yes, is there a documentation MR ready for it at Krita Documentation Repository? (Not a MR yet, but the changes are done: https://invent.kde.org/rasyuqaa/docs-krita-org/-/blob/rasyuqaa/jpegxl-docs-multipage/general_concepts/file_formats/file_jxl.rst)
Reminder: the reviewer is responsible for merging the patch, this is to ensure at the least two people can build the patch. In case a patch breaks the build, both the author and the reviewer should be contacted to fix the build. If this is not possible, the commits shall be reverted, and a notification with the reasoning and any relevant logs shall be sent to the mailing list, kimageshop@kde.org.