Bug summary

When plotting a 4x4 ImageGrid and using a discretised normalisation the colourbar at the bottom of a column does not use the entire available width if theextend argument in the normalisation is set to something other than'neither'. Below I have included example plots of what this looks like. As can be seen, only when setting extend to'neither' in the normalisation does the colourbar use the entire space on the x-axis from 0 to 10. The associated colourbar label also ends up not being centred (except whenextend is set to'both').

Code for reproduction

importmatplotlib.pyplotaspltimportmatplotlib.colorsasmcolorsimportnumpyasnpfrommpl_toolkits.axes_grid1importImageGriddefplot_grid(extend):im=np.arange(100).reshape((10,10))fig=plt.figure()grid=ImageGrid(fig,111,nrows_ncols=(2,2),axes_pad=0.2,cbar_mode='edge',cbar_location='bottom',cbar_pad=0.3,direction='column')bounds= [0,2,4,6,8,10]norm=mcolors.BoundaryNorm(boundaries=bounds,ncolors=256,extend=extend)c=grid[0].pcolormesh(im,norm=norm)cbar=grid[0].cax.colorbar(c)cbar.set_label('foo')c=grid[1].pcolormesh(im,norm=norm)cbar=grid[1].cax.colorbar(c)cbar.set_label('foo')c=grid[2].pcolormesh(im)cbar=grid[2].cax.colorbar(c)cbar.set_label('foo')c=grid[3].pcolormesh(im)cbar=grid[3].cax.colorbar(c)cbar.set_label('foo')fig.suptitle(f'extend=\'{extend}\'')fig.savefig(f'{extend}.png')plot_grid('neither')plot_grid('min')plot_grid('max')plot_grid('both')

Actual outcome

Settingextend equal to'min','max', or'both' shortens the colourbar causing it to not use all available horizontal space, and the colourbar label is not centred whenextend is set to'min' or'max'.

Expected outcome

Colourbars should always use the full width available, and the associated label should be centred.

Additional information

You should add an option foruv under how did you installmatplotlib, because that is how I installed it.

Operating system

Ubuntu 22.04

Matplotlib Version

3.10.1

Matplotlib Backend

qtagg

Python version

3.12.8

Jupyter version

No response

Installation

None