Bug summary

Setting bbox_inches in fig.savefig to a specified Bbox rather than "tight" resizes the colorbar relative to when bbox_inches is not set—the resulting colorbar is a lot larger than it should be.

Code for reproduction

import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt

x = np.linspace(0, 2*np.pi, 100)
y = np.linspace(0, 2*np.pi, 100)

X, Y = np.meshgrid(x,y)

fig, ax = plt.subplots(figsize=(4,4))

pc = ax.pcolormesh(x, y, np.sin(X)*np.sin(Y))
fig.colorbar(pc, ax=ax, aspect=40)

# Uncomment the first fig.savefig to get the correct output on the second call
# fig.savefig('nobbox_inches.png')
fig.savefig('bbox_inches.png', bbox_inches=mpl.transforms.Bbox([[0, 0], [4, 4]]))

Actual outcome

Expected outcome

Additional information

Calling fig.savefig without bbox_inches set first and then calling it again with bbox_inches set produces expected outcome.
Calling plt.show() prior to savefig also works.

Operating system

MacOS 12.2.1 (Monterey)

Matplotlib Version

3.5.1

Matplotlib Backend

inline (for interactive), png for plot, also a problem with pdf

Python version

3.9.10

Jupyter version

Jupyter lab 3.2.9

Installation

conda