This was completely broken due to the renderer ignoring s.xspan. As a
result, subplots could end up rendered multiple times if they spanned
neighboring subplots.
Quick example:
./scripts/plot.py test.csv -xx \
--subplot="-ya" \
--subplot-right="-yb" \
--subplot-below="-yc"
Fortunately the fix is easy, just make sure to increment x_ += s.xspan
as we render subplots across the x-axis.
Curiously the behavior was already correct for the y-axis, I guess
because the y-axis is quite a bit more complicated with how it crosses
multiple lines.
Christopher Haster
36c3a1467b