Composite images in PS to not respect axes background color

[mdboom]

When multiple images are placed on an axes, a composite image is created containing all of them. Unfortunately, since PS does not support alpha, the background of the axes does not show through. The obvious choice is to turn off image compositing, however, make_image still expands each image to fill the entire axes, so only the topmost image will be visible. This will require some finagling, but it seems the thing to do is to stop non-composited images from taking up the entire axes.

[mdboom]

Related to, but not resolved by, #1894

[tacaswell]

I think this is partially resolved by my PR which changed the background to white. The full fix for this would be to add the ability to pass in base color to that code.

[anntzer]

afaict this has been fixed, likely by the 2.0 image refactor?

from pylab import *

ax = plt.figure().add_subplot(facecolor="r")
ax.imshow(np.random.rand(4, 4, 4), extent=(0, 2, 0, 2))
ax.imshow(np.random.rand(4, 4, 4), extent=(1, 3, 1, 3))
ax.set(xlim=(0, 3), ylim=(0, 3))
ax.figure.savefig("/tmp/test.ps")
plt.show()

has the axes facecolor correctly showing through.