.. _misc-svg_filter_pie: misc example code: svg_filter_pie.py ==================================== .. plot:: /home/tcaswell/source/p/matplotlib/doc/mpl_examples/misc/svg_filter_pie.py :: """ Demonstrate SVG filtering effects which might be used with mpl. The pie chart drawing code is borrowed from pie_demo.py Note that the filtering effects are only effective if your svg renderer support it. """ import matplotlib matplotlib.use("Svg") import matplotlib.pyplot as plt from matplotlib.patches import Shadow # make a square figure and axes fig1 = plt.figure(1, figsize=(6, 6)) ax = fig1.add_axes([0.1, 0.1, 0.8, 0.8]) labels = 'Frogs', 'Hogs', 'Dogs', 'Logs' fracs = [15, 30, 45, 10] explode = (0, 0.05, 0, 0) # We want to draw the shadow for each pie but we will not use "shadow" # option as it does'n save the references to the shadow patches. pies = ax.pie(fracs, explode=explode, labels=labels, autopct='%1.1f%%') for w in pies[0]: # set the id with the label. w.set_gid(w.get_label()) # we don't want to draw the edge of the pie w.set_ec("none") for w in pies[0]: # create shadow patch s = Shadow(w, -0.01, -0.01) s.set_gid(w.get_gid() + "_shadow") s.set_zorder(w.get_zorder() - 0.1) ax.add_patch(s) # save from io import BytesIO f = BytesIO() plt.savefig(f, format="svg") import xml.etree.cElementTree as ET # filter definition for shadow using a gaussian blur # and lightening effect. # The lightening filter is copied from http://www.w3.org/TR/SVG/filters.html # I tested it with Inkscape and Firefox3. "Gaussian blur" is supported # in both, but the lightening effect only in the Inkscape. Also note # that, Inkscape's exporting also may not support it. filter_def = """ """ tree, xmlid = ET.XMLID(f.getvalue()) # insert the filter definition in the svg dom tree. tree.insert(0, ET.XML(filter_def)) for i, pie_name in enumerate(labels): pie = xmlid[pie_name] pie.set("filter", 'url(#MyFilter)') shadow = xmlid[pie_name + "_shadow"] shadow.set("filter", 'url(#dropshadow)') fn = "svg_filter_pie.svg" print("Saving '%s'" % fn) ET.ElementTree(tree).write(fn) Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)