Surprising alignment of (multiple) colorbars with constrained layout active #10627
Description
Bug report
Bug summary
The new experimental layout manager seems to produce a rather surprising alignment of two colorbars when one is shared by several Axes instances, and another one is simply stealing space from a single Axes instance. It seems like @jklymak might have a fix in mind, but he also have a day-job ^^: milestoning for 2.2 just in case he manages to have a shot in time for it.
NB: originally from Gitter.
Code for reproduction
import matplotlib.pyplot as plt
import numpy as np
# Dummy data
arr_shape = (64, 256)
vmin, vmax = 80.0, 120.0
arr_A = np.random.uniform(low=vmin, high=vmax, size=arr_shape)
arr_B = np.random.uniform(low=vmin, high=vmax, size=arr_shape)
rel_error = 100 * (arr_A - arr_B) / arr_A
# Plotting time!
fig, axs = plt.subplots(3, 1, constrained_layout=True)
# Raw data arrays, with a shared colorbar
for ax, arr, lbl in ((axs[0], arr_A, "Case A"), (axs[1], arr_B, "Case B")):
_im0 = ax.imshow(arr, vmin=vmin, vmax=vmax)
ax.set_title(lbl)
fig.colorbar(_im0, ax=axs[:2], label="Raw Data (a.u.)", aspect=2*20, pad=-12)
# Relative difference at the bottom, with its own colorbar
ax = axs[2]
_im1 = ax.imshow(rel_error, cmap="coolwarm",
vmin=min(rel_error.min(), -rel_error.max()),
vmax=max(rel_error.max(), -rel_error.min()))
ax.set_title("(A - B) / A")
fig.colorbar(_im1, ax=axs[2], label="Difference (%)", aspect=20)
# Cosmeticks
for ax in axs.flat:
ax.set_xticks([])
ax.set_yticks([])
plt.show()@jklymak I know, I know, it is not really “minimal”, but I was originally planning to show a use case rather than a MWE. And at least, it is a standalone example 😈.
Actual outcome
Expected outcome
Something closer to
Workaround
The figure in the Expected outcome section was produced by passing the supplementary parameter “pad=-12” in the relevant line:
fig.colorbar(_im0, ax=axs[:2], label="Raw Data (a.u.)", aspect=2*20, pad=-12)Matplotlib version
- Operating system: Linux (Fedora 27)
- Matplotlib version: 2.2.0rc1 from conda
- Python version: 3.6 from conda
Edit: English