Online plotter using matplotlib

OnlinePlotter.py

# Plot line per line, can be used as a serial plotter

import matplotlib.pyplot as plt
import numpy
import time
import math
import random


class OnlinePlotter:
	# Plot data as it arrives. DataLimit is the max number of data points in a view
	def __init__(self, dataLimit=500):
		self.limit = dataLimit
		self.h = None

	def update(self, valueArray):
		if self.h == None:
			self.h = []

			for x in valueArray:
				h = plt.plot(0, x)
				self.h.extend(h)

			plt.show(block=False)

		else:
			for i, h in enumerate(self.h):
				xdata = h.get_xdata()
				ydata = h.get_ydata()
				if len(xdata) > self.limit:
					xdata = xdata[-self.limit-1:]
					ydata = ydata[-self.limit-1:]

				h.set_xdata(numpy.append(xdata, xdata[-1]+1))
				h.set_ydata(numpy.append(ydata, valueArray[i]))
				plt.axes().relim() 
				plt.axes().autoscale_view()
				plt.draw()


def serialPlotter(port = "/dev/cu.usbserial-DA01L9R9"):
	import serial

	ser = serial.Serial(port, 9600, timeout=5)
	if not ser.isOpen():
		print "Could not open serial port %s" % port
		return

	plotter = OnlinePlotter(dataLimit = 50)

	line = ser.readline()
	Nplots = len(line.split())


	while True:
		line = ser.readline()
		if len(line.split()) != Nplots:
			print "Number of channels mismatch"
			continue

		values = []
		for v in line.split():
			values.append(float(v))
		print values
		plotter.update(values)



def TestOnlinePlotter():
	plotter = OnlinePlotter()
	
	x1 = 0
	x2 = 0

	for k in range(10000):
		x1 += random.random() - 0.5
		x2 = math.sin(k/10.0)
		newValues = [x1, x2]
		#print newValues
		plotter.update(newValues)
	
		#time.sleep(0.01)
	

	print "Press enter to quit"
	raw_input()


if __name__ == "__main__":
	# TestOnlinePlotter()

	serialPlotter()