After tearing my hair out inserting the OpenColorIO library into rawproc’s build system (Only LIkes Shared Libraries -gah!!), I’ve finally got a crude ociotransform tool to work. Right now, it only does OCIO::ROLE_SCENE_LINEAR → OCIO::ROLE_DEFAULT, which with @anon11264400’s Blender config.ocio does a “Linear sRGB/709” to “sRGB” transform, and it looks right. Since the chromaticities are the same, the only real change is with gamma.
I’m working on a Surface tablet using msys2, and my success came when I finally did the following: 1) install the msys2 OCIO package, and 2) turned off -static in the rawproc link line. All the other stuff I’m linking to is just .a files, so it stays static. I also started to unpack the OCIO public configs, but after about 1.5G of ACES stuff I aborted that and got @anon11264400’s Blender config, much, much smaller. I’m hoping Linux goes smoother, except I’ll have problems cross-building for Windows unless I pack the .dlls in the installer. Not my preference.
Next step is to figure out what parameters to expose in the tool pane. For sure, input and output colorspaces, I think, but I need to determine how transforms are built in the config files, because I don’t think I need to build them in the tool.
So, I turn off CMS (input.cms=0), open the raw with:
and insert as the first tool a colorspace convert to sRGB-elle-V4-g10.icc. Then, insert the ociotransform tool, and the gamma gets its due. Here’s a screenshot, ignore the ociotransform panel, I copied the colorspace panel code and I haven’t deleted the old widgets yet:
ocio on the Surface is a pig, ~6sec per transform for my 16MP D7000 images, so I multithreaded it and the time decreased to ~1.5sec, much better. Same general approach as multithreading cmsTransform in LittleCMS.
I started to figure out how to apply one of the LUTs to get a scaled display image, but I’m out of time, need to sleep now so I don’t sleep through my morning meeting.
The build thing is a bit of a roadblock, but I’ll definitely keep the code at least as a conditional compile.
(yes, I know, a lot of programming “language” above, but I think the coders will appreciate the story)