Hi I have attached a patch to "Bug 74224 – Add support for 16 bits per channel" [1] that makes it possible to use GIMP for opening, color correcting and saving 16-bits-per-channel PNGs using the operations under the Colors menu that are ported to GEGL such as Color Balance or Levels. For a technical description of the patch, refer to the bug report.
This was a weekend hack and raises an interesting question: shall we go for some kind of 16-bit support for GIMP 2.8? I think we should as I am confident we will be able to come up with something useful in the realm of high bit depths for 2.8. I don't think it will be hard to add support for loading some additional 16-bit image formats, allowing creation of 16-bit images and adding 16-bit capabilities to a set of basic tools. Even if we certainly won't be able to completely port everything to 16-bit in one release cycle it would show that we are making progress in this area. Just being able to color correct 16-bit PNGs covers one use case already. To convince yourself of that the patch actually makes GIMP do stuff in high bit depth: 1. Apply the patch, requires SVN trunk of GIMP, GEGL and babl. 2. Open a 16-bit PNG with a white-to-black gradient such as this [2] one I created using Krita. 3. Enable GEGL for the projection and color tools, the legacy code can't handle 16-bit image data. View -> Use GEGL and Colors -> Use GEGL. 4. Use Colors -> Levels and map the entire range of input to the output range [120, 135]. This will make the image look completely gray. Apply. 5. Use Colors -> Levels and map the input range [120, 135] to the full output range [0, 255]. Apply. After doing 5 the gradient will look intact if you do this on the 16-bit PNG with GEGL. If you do this on 8-bit data using the 8-bit legacy code paths the results will look terrible. Welcome to the start of the 16-bit GIMP era ;) BR, Martin [1] http://bugzilla.gnome.org/show_bug.cgi?id=74224 [2] http://www.chromecode.com/temp/gradient-16-bit.png _______________________________________________ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
