Hi,

I'm kind of new to Python and trying to create a plotting app for values read via RS232 from a sensor. I've managed (after some reading and copying examples online) to get a plot working that updates on a timer which is great. My only trouble is that I can't manage to get multiple data series into the same plot. Does anyone have a solution to this?

This is the code that I've worked out this far:

import os
import pprint
import random
import sys
import wx

# The recommended way to use wx with mpl is with the WXAgg backend
import matplotlib
matplotlib.use('WXAgg')
from matplotlib.figure import Figure
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigCanvas, NavigationToolbar2WxAgg as NavigationToolbar
import numpy as np
import pylab


DATA_LENGTH = 100
REDRAW_TIMER_MS = 20


def getData():
 return int(random.uniform(1000, 1020))


class GraphFrame(wx.Frame):
 # the main frame of the application
    def __init__(self):
        wx.Frame.__init__(self, None, -1, "Usart plotter", size=(800,600))

        self.Centre()

        self.data = []
        self.paused = False

        self.create_menu()
        self.create_status_bar()
        self.create_main_panel()

        self.redraw_timer = wx.Timer(self)
        self.Bind(wx.EVT_TIMER, self.on_redraw_timer, self.redraw_timer)        
        self.redraw_timer.Start(REDRAW_TIMER_MS)

    def create_menu(self):
        self.menubar = wx.MenuBar()

        menu_file = wx.Menu()
        m_expt = menu_file.Append(-1, "&Save plot\tCtrl-S", "Save plot to file")
        self.Bind(wx.EVT_MENU, self.on_save_plot, m_expt)
        menu_file.AppendSeparator()
        m_exit = menu_file.Append(-1, "E&xit\tCtrl-X", "Exit")
        self.Bind(wx.EVT_MENU, self.on_exit, m_exit)

        self.menubar.Append(menu_file, "&File")
        self.SetMenuBar(self.menubar)

    def create_main_panel(self):
        self.panel = wx.Panel(self)

        self.init_plot()
        self.canvas = FigCanvas(self.panel, -1, self.fig)

  # pause button
        self.pause_button = wx.Button(self.panel, -1, "Pause")
        self.Bind(wx.EVT_BUTTON, self.on_pause_button, self.pause_button)
        self.Bind(wx.EVT_UPDATE_UI, self.on_update_pause_button, self.pause_button)

        self.hbox1 = wx.BoxSizer(wx.HORIZONTAL)
        self.hbox1.Add(self.pause_button, border=5, flag=wx.ALL | wx.ALIGN_CENTER_VERTICAL)

        self.vbox = wx.BoxSizer(wx.VERTICAL)
        self.vbox.Add(self.canvas, 1, flag=wx.LEFT | wx.TOP | wx.GROW)        
        self.vbox.Add(self.hbox1, 0, flag=wx.ALIGN_LEFT | wx.TOP)

        self.panel.SetSizer(self.vbox)
        #self.vbox.Fit(self)

    def create_status_bar(self):
        self.statusbar = self.CreateStatusBar()

    def init_plot(self):
        self.dpi = 100
        self.fig = Figure((3.0, 3.0), dpi=self.dpi)

        self.axes = self.fig.add_subplot(111)
        self.axes.set_axis_bgcolor('white')
        self.axes.set_title('Usart data', size=12)

        pylab.setp(self.axes.get_xticklabels(), fontsize=8)
        pylab.setp(self.axes.get_yticklabels(), fontsize=8)

        # plot the data as a line series, and save the reference 
        # to the plotted line series
        #
        self.plot_data = self.axes.plot(
            self.data, 
            linewidth=1,
            color="blue",
            )[0]

    def draw_plot(self):
  # redraws the plot
        xmax = len(self.data) if len(self.data) > DATA_LENGTH else DATA_LENGTH         
        xmin = xmax - DATA_LENGTH
       ymin = 0
       ymax = 4096

       self.axes.set_xbound(lower=xmin, upper=xmax)
       self.axes.set_ybound(lower=ymin, upper=ymax)

  # enable grid
       #self.axes.grid(True, color='gray')

        # Using setp here is convenient, because get_xticklabels
        # returns a list over which one needs to explicitly 
        # iterate, and setp already handles this.
        #  
        pylab.setp(self.axes.get_xticklabels(), visible=True)

        self.plot_data.set_xdata(np.arange(len(self.data)))
        self.plot_data.set_ydata(np.array(self.data))

        self.canvas.draw()

    def on_pause_button(self, event):
        self.paused = not self.paused

    def on_update_pause_button(self, event):
        label = "Resume" if self.paused else "Pause"
        self.pause_button.SetLabel(label)

    def on_save_plot(self, event):
        file_choices = "PNG (*.png)|*.png"

        dlg = wx.FileDialog(
            self, 
            message="Save plot as...",
            defaultDir=os.getcwd(),
            defaultFile="plot.png",
            wildcard=file_choices,
            style=wx.SAVE)

        if dlg.ShowModal() == wx.ID_OK:
            path = dlg.GetPath()
            self.canvas.print_figure(path, dpi=self.dpi)
            self.flash_status_message("Saved to %s" % path)

    def on_redraw_timer(self, event):
        if not self.paused:
            newData = getData()
            self.data.append(newData)

        self.draw_plot()

    def on_exit(self, event):
        self.Destroy()

    def flash_status_message(self, msg, flash_len_ms=1500):
        self.statusbar.SetStatusText(msg)
        self.timeroff = wx.Timer(self)
        self.Bind(
            wx.EVT_TIMER, 
            self.on_flash_status_off, 
            self.timeroff)
        self.timeroff.Start(flash_len_ms, oneShot=True)

    def on_flash_status_off(self, event):
        self.statusbar.SetStatusText('')


if __name__ == '__main__':
    app = wx.PySimpleApp()
    app.frame = GraphFrame()
    app.frame.Show()
    app.MainLoop()