Hi,
I’m writing a script to plot data being read from a serial connection in real time. I’m trying to use an idle_event callback to continually read the incoming data and plot it. The problem is that the callback is only getting invoked once. I found this page: http://www.scipy.org/Cookbook/Matplotlib/Animations, which suggests using backend-specific stuff. This is intended to be a quick-and-dirty thing though so I was really hoping to avoid that. Here’s my code:
def OnIdle(event):
global xData
global yData
data = ReadSerialData()
if data != None:
yData.append(data)
if len(yData) > GRAPH_WINDOW_SIZE:
del yData[0]
else:
xData.append(len(xData))
line.set_xdata(xData)
line.set_ydata(yData)
pylab.draw()
# end if data != None
end OnIdle
if name == ‘main’:
pylab.ion()
fig = pylab.figure()
ax = fig.add_subplot(1,1,1)
line = ax.add_line(pylab.Line2D([], []))
ax.set_ylim(0, 100)
ax.set_xlim(0, GRAPH_WINDOW_SIZE)
fig.canvas.mpl_connect('idle_event', OnIdle)
pylab.show()
end name == ‘main’
Oh btw, I’m positive that ReadSerialData is not blocking and that it’s making it through the whole idle handler. I’m running on 64 bit Linux with Python 2.6. According to --verbose-helpful, I’m using matplotlib version 0.98.5.2 and GTKAgg version 2.14.1. Am I doing something wrong or do I really need to go backend-specific?
Thanks,
Mark
I tried your suggestion of returning True but it didn’t solve the problem. Oh well, not the end of the world. Being a die-hard KDE user, I started trying to get things working with Qt. I got my animation working but thus far haven’t been able to catch key press events. My guess is that I’m just missing something about how it’s supposed to be done so I’ll probably figure it out.