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colormaps don't have getters for under, over, bad colors. #16075
Description
Bug report
Bug summary
colormaps don't have getters for under, over, bad colors (although the corresponding setters exist).
I am writing a function that accepts a colormap as an argument. I want to ensure that the colormap passed to the function has the same color for the "bad" and "under" conditions. The only way around this is to access "private" attributes cmap._rgba_under, cmap._rgba_bad as shown below.
Code for reproduction
cmap = plt.get_cmap('cividis')
cmap.set_bad('k')
cmap.set_under('k')
assert cmap._rgba_bad == cmap._rgba_underIf adding getters (for under, over, bad colors) for the colormaps sounds like a good improvement, i would be interested in submitting a PR.
Actual outcome
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Expected outcome
Matplotlib version
- Operating system:
- Matplotlib version:
- Matplotlib backend (
print(matplotlib.get_backend())): - Python version:
- Jupyter version (if applicable):
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Activity
anntzer commentedon Jan 2, 2020
Actually I think the setters should not exist (see #14645)...
I think you can do
cmap(+np.inf)cmap(-np.inf)cmap(np.nan)to get the over/under/bad values, not sure if it warrants a separate API?pharshalp commentedon Jan 2, 2020
Thanks.
MaozGelbart commentedon Jan 28, 2020
@anntzer perhaps it warrants a different API? The difference is distinguished when bad/under/over were not set at all. Querying the cmap for such cases will result with the default extreme colors even when these were never set by the cmap creator. With getters I expect to get the set value (if provided) or None (if these weren't set at all).
jklymak commentedon Jan 28, 2020
Not sure I follow. By default you definitely want a color if the mapped value is over vmax.
MaozGelbart commentedon Jan 28, 2020
For sure, but currently I can't tell apart if
set_overwas called prior to that or I'm getting the default extreme value from the colormap. So by having aget_overthat returns None ifset_overwas never called (or the input to set_over in the case it was called), I can distinguish between the two cases. This may prove useful for manipulating colormaps.pharshalp commentedon Jan 28, 2020
@MaozGelbart