pyQt Matplotlib widget live data updates

Question

Writing in Python 2.7 using pyQt 4.8.5:

How may I update a Matplotlib widget in real time within pyQt? Currently I\'m sampling data (random.gauss for now), appending

Answer 1

One idea would be to update only the graphics object after the first plot was done. axes.plot should return a Line2D object whose x and y-data you can modify:

http://matplotlib.org/api/artist_api.html#matplotlib.lines.Line2D.set_xdata

So, once you have the line plotted, don't delete and plot a new one, but modify the existing:

def updateData(self):
    if not hasattr(self, 'line'):
        # this should only be executed on the first call to updateData
        self.ui.graph.axes.clear()
        self.ui.graph.axes.hold(True)
        self.line = self.ui.graph.axes.plot(self.ValueTotal,'r-')
        self.ui.graph.axes.grid()
    else:
        # now we only modify the plotted line
        self.line.set_xdata(np.arange(len(self.ValueTotal))
        self.line.set_ydata(self.ValueTotal)
    self.ui.graph.draw()