Matplotlib: matplotlib and zopeΒΆ

0. Prerequisites: You need to have the following installed to successfully run this example: Zope, Matplotlib (on top of Zope's Python), Python Image Library (PIL). And one more thing - probably every body does this right, but just in case - zope instance home directory has to be writable, for following to work.

1. Create a file (e.g. mpl.py) in INSTANCEHOME\Extensions:

import matplotlib
matplotlib.use('Agg')
from pylab import *
from os import *
from StringIO import StringIO
from PIL import Image as PILImage
from matplotlib.backends.backend_agg import FigureCanvasAgg
def chart(self):
    clf()
    img_dpi=72
    width=400
    height=300
    fig=figure(dpi=img_dpi, figsize=(width/img_dpi, height/img_dpi))
    x=arange(0, 2*pi+0.1, 0.1)
    sine=plot(x, sin(x))
    legend(sine, "y=sin x", "upper right")
    xlabel('x')
    ylabel('y=sin x')
    grid(True)
    canvas = FigureCanvasAgg(fig)
    canvas.draw()
    size = (int(canvas.figure.get_figwidth())*img_dpi, int(canvas.figure.get_figheight())*img_dpi)
    buf=canvas.tostring_rgb()
    im=PILImage.fromstring('RGB', size, buf, 'raw', 'RGB', 0, 1)
    imgdata=StringIO()
    im.save(imgdata, 'PNG')
    self.REQUEST.RESPONSE.setHeader('Pragma', 'no-cache')
    self.REQUEST.RESPONSE.setHeader('Content-Type', 'image/png')
    return imgdata.getvalue()
  1. Then create an external method in ZMI (e.g. Id -> mplchart, module name -> mpl, function name -> chart).
  2. Click the Test tab and you should see the sine plot.

Section author: AndrewStraw, Unknown[106], Unknown[107]