Color Map Editor log scaling issues


There seems to be something off with the TF viewer in the Color Map Editor when the Use Log Scale When mapping Data To Colors is checked. I would expect the TF viewer to look similar to the 3D view legend but it doesn’t:

Here’s the
state file (335.1 KB)

This is with PV 5.12 on Linux using the downloaded installer.

Is this incorrect behavior or is this confusion on my end?


Hey Andy,

In the editor, the x-axis values are evenly spaced, not in a logarithmic space, hence the color legend is “squished” on the left and “stretched” on the right when using log scaling. In the color legend, the vertical axis is scaled logarithmically, so the color legend is not squished or stretched on either side - rather, the axis values change logarithmically. So I don’t think anything funny is happening here. We just seeing the color map drawn in two different coordinate spaces.

We see the same thing in 5.10.1 with the old color map editor

There is a question of whether we should logarithmically scale the x-axis in the color map editor. That wouldn’t be unreasonable IMO.

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Yeah, I was guessing that the editor doesn’t have the x-axis in logarithmic space. I personally think that the editor’s x-axis should have the same scaling as the TF. Trying to modify the TF at the low end of the values in the editor seems to be a bit unwieldy.

If there isn’t any pushback to this idea then I can create a gitlab issue for this.

Yeah, I think it makes sense to log-scale the x-axis in the editor. At least I don’t see a reason not to.

Thanks for the info! I’ve made a GitLab issue at I’ve initially assigned @cory.quammen to this issue. Feel free to reassign though. Also, I targeted PV 5.13 thinking that this is hopefully an easy fix but this isn’t an urgent fix so if it slips that should be ok.