[EN] experimental feature : color mapping between images (exposure and color calibration)

[@okay1904]

Cool. Will be most useful. May inspire me to setup Windows Linux Subsystem, so I can compile and use darktable as a Linux app running in Windows, and not have to do a custom Windows native compile, or wait until July 2022! Thanks Aurelien. Merry Xmas, and a happy new year to you.

Merry Christmas to you too !

[@europlatus]

This is a great feature, thank you Aurélien! A very minor point, but is there a reason the sliders are ordered Lhc instead of Lch as you might expect from the acronym?

Because you usually want to setup hue before chroma, so it makes more sense in this order.

[@93Logen]

The color mapping module does something similar as far as I understand.

Not at all. Color mapping uses clustered means in Lab along with histogram normalization (CLAHE). In other words, it tries to do something very complicated and the results are arguably ugly. Also it crashes on Windows for technical reasons and comes later in the pipe, so don't expect it to normalize your image for the secondary color-grading.

[@hengzhang6948]

太硬核了