DJV3 Color Correction tools

[danbradham]

Hey Darby,

The latest release is fantastic. I love the care you put into refining the UI and just making the app more comfortable in general. I especially like your minimal set of color correction tools. I was wondering if you have a write-up / a location in the code base to look at / a reference for your implementation that you could share about your color correction implementation. For example, what working space are you performing the color corrections in, what order of operations do you use for the corrections, etc. As a quick set of CC tools, I found them to be both simple and powerful.

[darbyjohnston]

Hi, and thanks! The color tools are a mix of functionality provided by OpenColorIO and some simple functions. If you are interested, most of the code is here in GLSL:
https://github.com/darbyjohnston/tlRender/blob/main/lib/tlTimelineGL/RenderShaders_GL_4_1.cpp

The order of operations is:

• Brightness, contrast, etc.
• Levels
• EXR display functions (from the OpenEXR example viewer)
• Soft clip
• OCIO / LUTs
• Color channel display

The code is pretty monolithic, it would be nice to break it up at some point and allow the operations to be re-ordered. It would also probably be good to add a step to convert the file color space into some common color space, currently the color functions are applied to whatever color space the file is in.

[danbradham]

Cool, thanks for the write-up!