[Bug]: 3.5.0 colorbar outside of its axis when saved into vectorial formats #21672

Bug summary

For some figure/subplot/colorbar axis aspect ratios, the colorbar is outside of its axes when saved into vectorial formats (pdf, svg).

Code for reproduction

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 100, 100)
y = np.linspace(0, 100, 100)
z = x[None, :]**2 + y[:, None]**2

fig, axarr = plt.subplots(1, 2, figsize=(3, 2.8789385625),
                          constrained_layout=True, sharey=True)
ax = axarr[0]
a = ax.pcolormesh(x, y, z, snap=True)
fig.colorbar(a, ax=ax, location='top')
#
ax = axarr[1]
a = ax.pcolormesh(x, y, z, snap=True)
fig.colorbar(a, ax=ax, location='top')
plt.savefig('test_colorbar.pdf')
plt.savefig('test_colorbar.svg')
plt.savefig('test_colorbar.png', dpi=800)

Actual outcome

Expected outcome

The colorbar should be within its axis, and not shifted upward.

Additional information

• It does not occur when the figure is saved to non-vectorial format (i.e png, etc ..)
• In this case, it does not occur for all figure aspect ratios.
• It was already the case in matplotlib 3.4.3

Operating system

Ubuntu 20

Matplotlib Version

3.5.0

Matplotlib Backend

QtAgg

Python version

3.8.10

Jupyter version

No response

Installation

pip