Unexpected behavior when explicitly providing colors and unevenly spaced levels

Description

When supplying my own colors and unevenly spaced levels explicitly, I observe an unexpected behavior where some colors are omitted and others are repeated.

Steps to reproduce

import proplot as pplt
import numpy as np

N=20
state=np.random.RandomState(51423)
data=np.cumsum(state.rand(N, N), axis=1)

colors=['white','indigo1','indigo3','indigo5','indigo7','indigo9','yellow1','yellow3','yellow5','yellow7','yellow9','violet1','violet3']

fig,axs=pplt.subplots(nrows=2, ncols=1, refheight=3.5)

axs[0].pcolormesh(data, levels=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12],
                  colors=colors, colorbar='r', extend='both', colorbar_kw={'label':'Expected color distribution'})

axs[1].pcolormesh(data,levels=[1., 1.25, 1.5, 2., 2.5, 3., 3.75, 4.5, 6., 7.5, 9., 12.],
                  colors=colors, colorbar='r', extend='both', colorbar_kw={'label':'Unexpected color distribution'})

Expected behavior: I expected that all 13 named colors would still show when mapped to the unevenly spaced levels on axs[1].

Actual behavior: In this example on axs[1], some colors are omitted and replaced by others. I also observe this issue when providing my own RGB tuples.

Equivalent steps in matplotlib

Explicitly providing named colors and unevenly spaced levels in Matplotlib gives the desired behavior.

Proplot version

ProPlot 0.9.5 Matplotlib 3.4.3 Python 3.9.7

[AWSisco]

Thanks for such a quick turnaround on getting this resolved. Much appreciated!

[lukelbd]

Here’s your example after the update. Note some ticks on the right “linear” colorbar are missing by default (to prevent overcrowding) while ticks on the left SegmentedNorm colorbar are all shown (to avoid hiding the locations of non-linear thresholds in the scaling).

import proplot as pplt
import numpy as np
N=20
state=np.random.RandomState(51423)
data=np.cumsum(state.rand(N, N), axis=1)
colors=['white','indigo1','indigo3','indigo5','indigo7','indigo9','yellow1','yellow3','yellow5','yellow7','yellow9','violet1','violet3']
levels_even = pplt.arange(1,12,1)
levels_uneven=[1., 1.25, 1.5, 2., 2.5, 3., 3.75, 4.5, 6., 7.5, 9., 12.]
fig, axs = pplt.subplots(ncols=2, refwidth=3.)
axs[0].pcolor(np.random.rand(10, 10) * 12, levels=levels_uneven, colors=colors, colorbar='r', extend='both')
axs[1].pcolor(np.random.rand(10, 10) * 12, levels=levels_even, colors=colors, colorbar='r', extend='both')