Feature request: add "black biased" alternative

[JonathanILevi]

Lowering contrast can also be done by making white darker (rather than black lighter). This is easier on the eyes in a dark room and nicer to look at on low quality LCD monitors that only get so dark.

[vn971]

@JonathanILevi if you want, I can make you a *.glsl that makes colors darker, so you can test it out and compare result.
Is that something you'd want?

[vn971]

Feel free to reply if you'd want to test the other low-contrast alternative. Closing for now as the current issue doesn't seem like a bug specifically -- rather a question.

[vn971]

Apparently more than one person wants to have it, so I'll re-open and ask for contributors.

If anybody wants to solve this issue, please edit the script shift_whiteish.glsl to have another constant float black_bias in addition to white_bias. Letting the user only change that value then and observe the result.

Additionally, if one has time, I'd be very happy to accept a merge request that merges the "white-biased" alternatives in only the general one in README. So that you'd have just the basic transformation there out of the box with constants that we like the most. But the user would then be encouraged play with constants, if they want.

Feel free to ask questions on the issue or the proposal.