mpl_test.py

# coding=utf-8
from matplotlib.figure import Figure

def make_example_pie():
    """
    Follows the simple pie chart demo[1] from matplotlib's gallery, but
    rewritten in a cleaner fashion that can be used for PNG rendering.
    
    [1] http://matplotlib.sourceforge.net/examples/pylab_examples/pie_demo.html
    """
    # with DPI@100px/in, this renders a 600x600 image
    fig = Figure(figsize=(6,6), dpi=100, frameon=False)
    ax = fig.add_subplot(111)
    
    labels = 'Frogs', 'Hogs', 'Dogs', 'Logs'
    fracs = [15,30,45, 10]
    
    explode=(0, 0.05, 0, 0)
    
    ax.pie(fracs, explode=explode, labels=labels, autopct='%1.1f%%', shadow=True)
    ax.set_title('Raining Hogs and Dogs', bbox={'facecolor':'0.8', 'pad':5})
    
    return fig

if __name__ == "__main__":
    # Call the function above, which renders the figure.
    fig = make_example_pie()
    
    # Write it to a file.
    from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas
    canvas = FigureCanvas(fig)
    output_file = open("test.png","wb")
    canvas.print_png(output_file)
    output_file.close()