[ENH]: Ignore ticklabels in colorbar constrained-positioning

[anntzer]

Problem

Sometimes, trying to stick a colorbar next to its "parent" axes by using pad=0 will "fail" if the axes has a ticklabel that extends beyond the axes' spines:

from pylab import *
fig = figure(layout="constrained", figsize=(8, 4))
axs = fig.subplots(1, 2)
for i, ax in enumerate(axs):
    im = ax.imshow(np.arange(9).reshape((3, 3)), aspect="auto")
    fig.colorbar(im, pad=0, ticks=[])
axs[0].set(xlim=(-.5, 2.5), xticks=[0, 1, 2], yticks=[])
axs[1].set(xlim=(0, 3), xticks=[0, 1, 2, 3], yticks=[])
show()

see the small extra spacing between the left axes and the left colorbar, not present on the right.

Proposed solution

I'm not sure this can reliably be handled automatically (the desirable behavior also depends on whether the colorbar's vertical extent goes goes beyond the axes' vertical extent, which will depend on how exactly the colorbar is positioned, whether the parent axes uses fixed aspect (here I disabled fixed aspect ratio on imshow).

But it would be nice if one could at least tweak that manually with something like axs[1].xaxis.set_in_layout(False). Bonus points if one can do set_in_layout("y"), i.e. take the xaxis in account but only for its vertical extent (we don't want the labels to fall off below the figure), not for its horizontal extent.

[timhoffm]

As a rough guess this is medium difficulty.

[jklymak]

There are different paths here. The set_inlayout('x') route is probably fine and not very hard

Somehow doing this all the time is a bad idea. People have long ticklabels and you dont want those spilling over into the next axes.

Somehow detecting when it is wanted because I have a colorbar adjacent seems very hard

If I wanted the colorbar to hang exactly off the axes I would use inset_axes

[anntzer]

As noted above I agree doing this automatically is not particularly reasonable.

[oliviavanzandt]

@anntzer Can I be assigned this issue to work on?

[QuLogic]

We don't assign issues; if you want to work on this, then adding a note here is all you need to do.

[jayyxiao]

I will try this issue.