Hi I have attached a patch to "Bug 74224 – Add support for 16 bits perchannel" [1] that makes it possible to use GIMP for opening, colorcorrecting and saving 16-bits-per-channel PNGs using the operationsunder the Colors menu that are ported to GEGL such as Color Balance orLevels. For a technical description of the patch, refer to the bug report. This was a weekend hack and raises an interesting question: shall we gofor some kind of 16-bit support for GIMP 2.8? I think we should as I amconfident we will be able to come up with something useful in the realmof high bit depths for 2.8. I don't think it will be hard to add supportfor loading some additional 16-bit image formats, allowing creation of16-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 to16-bit in one release cycle it would show that we are making progress inthis area. Just being able to color correct 16-bit PNGs covers one usecase already. To convince yourself of that the patch actually makes GIMP do stuff inhigh 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] oneI created using Krita. 3. Enable GEGL for the projection and color tools, the legacy code can'thandle 16-bit image data. View -> Use GEGL and Colors -> Use GEGL. 4. Use Colors -> Levels and map the entire range of input to the outputrange [120, 135]. This will make the image look completely gray. Apply. 5. Use Colors -> Levels and map the input range [120, 135] to the fulloutput range [0, 255]. Apply. After doing 5 the gradient will look intact if you do this on the 16-bitPNG with GEGL. If you do this on 8-bit data using the 8-bit legacy codepaths 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 listGimp-developer@xxxxxxxxxxxxxxxxxxxxxxxxxxx://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
