Am 26.12.2012 19:18, schrieb Tobias Ellinghaus: > Am Mittwoch, 26. Dezember 2012, 18:04:31 schrub Ulrich Pegelow: >> Hi guys, > > Hi. > > [...] > >> For that reason I developed a general dithering module which comes late >> in pixelpipe, just before gamma. It supports random dither and error >> diffusion (Floyd-Steinberg). The latter with just a few output options. >> I left some room for future enhancements. Namely one could think about >> dithering into a user-defined color palette and such. > > Very nice. Since I had general banding issues lately I thought about > something > like that, too. My idea was to make it more like a core feature (technically > it would probably sit in the code that changes color depth from float to > $WHATEVER) and trigger it when exporting to anything but 32bit float AND some > option in the export module is checked. Not sure if that is a good idea, but > dithering certainly isn't needed when exporting to high bit depth formats. >
After our discussion yesterday on IRC here comes a proposal. I suggest to add a dither option "floyd-steinberg auto" to the module. This should be the new default value, and module dithering should also be switched on by default - similarly to module sharpen. When in auto mode, the module receives the desired output format via a value that is put in piece->pipe when the pixelpipe is initialized. This way we could transparently handle all standard cases without needed actions on users side. Display output, JPEG and such are dithered to 8-bit. 16-bit TIFFs and PNGs are handled properly and 32-bit float openEXR are not dithered at all. As this would be handled in a normal module, users are still free to set other defaults (like b&w dithering) and we are free to add new creative dithering techniques in future (like dithering into indexed colors). Not fully sure in which module group dithering should go. Maybe into the correction group. Most frequently the module is needed to avoid banding artifacts - from user's perspective that's a correction. Ulrich > > Tobias > ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnmore_122712 _______________________________________________ darktable-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-devel
