#!/usr/bin/python

from matplotlib.figure import Figure
from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas
# from matplotlib.backends.backend_gd import FigureCanvasGD as FigureCanvas
import sys

figure = Figure()
ax = figure.add_subplot(111)
ax.plot([1, 5, 3])
canvas = FigureCanvas(figure)

# This works to save image to a file as a PNG
canvas.print_figure("foo.png")

# This works to send image as a PNG to stdout
# canvas.print_figure(sys.stdout)

# Works with GD, but with Agg this doesn't work, error is
# File "/usr/lib/python2.3/site-packages/matplotlib/backends/backend_agg.py", line 453, in print_figure
#   self.renderer._renderer.write_png(filename)
# TypeError: Could not convert object to file pointer
import StringIO
buffer = StringIO.StringIO()
canvas.print_figure(buffer)
print len(buffer.getvalue())