PR Summary

We often have the situation where we have a grid of fixed-aspect axes, and they end up with too much space in one direction or the other:

For simple cases, it is not hard to fix this, as is done with this PR:

API:

As with previous efforts at doing this the API is a bit klunky, but I think it needs to be optional so we need something.

import matplotlib.pyplot as plt
import numpy as np

nrows = 2
ncols = 3
for compress in [False, True]:
    fig, axs = plt.subplots( nrows, ncols, figsize=(4,4),
                            constrained_layout={'compress':compress}, 
                            sharex=True, sharey=True)
    fig.patch.set_facecolor("0.9")
    #fig.set_constrained_layout_pads(compress=True)

    for i in range(nrows):
        for j in range(ncols):
            ax = axs[i, j]
            ax.set_aspect(1)
            pc = ax.pcolormesh(np.random.randn(30, 30))
    fig.colorbar(pc, ax=axs)
    fig.savefig(f'/Users/jklymak/downloads/Compress{compress}.png', dpi=100)

PR Checklist

• Has pytest style unit tests (and pytest passes).
• Is Flake 8 compliant (run flake8 on changed files to check).
• New features are documented, with examples if plot related.
• Documentation is sphinx and numpydoc compliant (the docs should build without error).
• Conforms to Matplotlib style conventions (install flake8-docstrings and run flake8 --docstring-convention=all).
• New features have an entry in doc/users/next_whats_new/ (follow instructions in README.rst there).
• API changes documented in doc/api/next_api_changes/ (follow instructions in README.rst there).