👍 This now needs a re-base due to merging #5342

Only suggestion would be to filter out the *_r colormaps and add a 'reverse' check box.

Is there a generic way to get the reverse of a colormap? The current colormap could be a user-defined one, in which case it needs to be available in the combobox, but then the user may pick to use its reversed form instead, in which case I need to generate that colormap on the fly.
It does seem to be a good idea though.

There was some discussion of adding such a method, but I don't think it went anywhere. In cm.py there are functions that are used to reverse the specifications (and are how we generate the *_r color maps, but I do not know if they can be made to work on a generic color map.

If the checkbox is going to take more than 15min, I would say skip it for this PR.

I'd say it will :-) (specifically for this part, the rest is not that hard)

Kindly bumping the issue. (If there's no easy way to reverse a cmap I'll skip that functionality for now.)

Seems fine, but this needs a rebase on current master.

Done (with no rebase conflict).