Matplotlib

Using Matplotlib in Web Apps

I wanted to write a Python web app that would call Matplotlib to visualize some data on the back end, and serve it up to a browser window on the front end.

Initially I saw [webplotlib https://pypi.python.org/pypi/webplotlib/0.1], which looked promising, but wrapped all of matplotlib into two dinky kinds of plots: time series, and bar charts. I needed something that, like webplotlib, could communicate a figure to a browser, but something that, unlike webplotlib, still kept the full functionality of matplotlib.

The fix was easy. The core functionality of webplotlib is passing a figure as a string to the browser; this is about 4 lines. The rest is entirely case-dependent.

Let's walk through how to do this.

Part 1: Create Your Figure

Some quick code to make a dummy figure:

import matplotlib.pylab as plt
from numpy.random import *

fig = plt.figure()
ax1 = fig.add_subplot(1,2,1)
ax2 = fig.add_subplot(1,2,2)

x = range(10)
y1 = rand(10,)
y2 = 100*rand(10,)

ax1.plot(x,y1,'b-')
ax2.plot(x,y2,'r-')