Adding artists without changing the underlying Axes etc.
I have implemented speedups based on the copy_from_bbox() and
restore_region() APIs (i.e., blit APIs) in conjunction with an Agg
canvas (my destination is actually a file, not screen).
I create a bar() plot, then grab the plot with copy_from_bbox(), then I
create Line2D() artists and add them using ax.add_line(). Following
this, I remove the artists, restore_region() and wash, rinse, repeat().
I'm finding that the process can lead to creep in data to screen
transforms, which I guess must be due to bounding box changes when I add
lines that may exceed the bbox. That's my theory.
Is there a mechanism or recommended methodology to tell artists (and/or
the axes they are being added to) not to recalculate anything, so that
the underlying plot remains unchanged by the add()?