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()
