python - Create a figure that is reference counted

Question

It seems that the standard way of creating a figure in matplotlib doesn't behave as I'd expect in python: by default calling fig = matplotlib.figure() in a loop will hold on to all the figures created, and eventually run out of memory.

There are quite a few posts which deal with workarounds, but requiring explicit calls to matplotlib.pyplot.close(fig) seems a bit hackish. What I'd like is a simple way to make fig reference counted, so I won't have to worry about memory leaks. Is there some way to do this?

Answer 1

If you create the figure without using plt.figure, then it should be reference counted as you expect. For example (This is using the non-interactive Agg backend, as well.)

from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas
from matplotlib.figure import Figure

# The pylab figure manager will be bypassed in this instance.
# This means that `fig` will be garbage collected as you'd expect.
fig = Figure()
canvas = FigureCanvas(fig)
ax = fig.add_subplot(111)