I've run into some performance issues with a GUI that I'm working on. Specificially I'm using wxPython as the backend for several matplotlib figures which I've embedded in the canvas. I've gotten the basic functionality working with a simple self.axes.clear() and self.axes.plot() command, but I can't seem to get any sort of reasonable frame rates using this method. After performing a search it seems that if I were using a plot object that I I could reset the xdata and ydata then redraw the figure to obtain a faster refresh rate. Unfortunately, the layout that I'm using precludes the use of the plot object, so I've implemented the code using the axes() object. As far as I can tell the axes() object does not have any equivalent methods for setting the xdata and ydata (see this post: How to update a plot in matplotlib?). Here's the code I'm using:
import sys,os,csv
import numpy as np
import wx
import matplotlib
import pylab
from matplotlib.figure import Figure
from matplotlib.backends.backend_wxagg import \
FigureCanvasWxAgg as FigCanvas, \
NavigationToolbar2WxAgg as NavigationToolbar
class UltrasoundDemoGUI(wx.Frame):
title = ' Ultrasound Demo '
def __init__(self):
wx.Frame.__init__(self, None, -1, self.title)
self.create_menu()
self.statusbar = self.CreateStatusBar()
self.create_main_panel()
self.dataMon = pylab.randn(100,1);
self.dataBi = pylab.randn(100,1);
self.dataLoc = pylab.randn(100,1);
self.redraw_timer = wx.Timer(self)
self.Bind(wx.EVT_TIMER, self.on_redraw_timer, self.redraw_timer)
self.redraw_timer.Start(300)
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.dpi = 100
self.figSignals = Figure((12, 5.0), dpi=self.dpi)
self.canvas = FigCanvas(self.panel, -1, self.figSignals)
rectSubplotMono = .1, .55, .4, .4
self.axesMono = self.figSignals.add_axes(rectSubplotMono)
rectSubplotBi = .1, .05, .4, .4
self.axesBi = self.figSignals.add_axes(rectSubplotBi)
rectSubplotLoc = .55, .05, .4, .9
self.axesLoc = self.figSignals.add_axes(rectSubplotLoc)
self.axesMono.set_axis_bgcolor('white')
self.axesBi.set_axis_bgcolor('white')
self.axesLoc.set_axis_bgcolor('white')
self.axesMono.set_title('Raw Ultrasound Signal', size=12)
pylab.setp(self.axesMono.get_xticklabels(), fontsize=8)
pylab.setp(self.axesMono.get_yticklabels(), fontsize=8)
pylab.setp(self.axesBi.get_xticklabels(), fontsize=8)
pylab.setp(self.axesBi.get_yticklabels(), fontsize=8)
pylab.setp(self.axesLoc.get_xticklabels(), fontsize=8)
pylab.setp(self.axesLoc.get_yticklabels(), fontsize=8)
# plot the data as a line series, and save the reference
# to the plotted line series
#
self.dataMono = pylab.randn(100,1)
self.dataBi = pylab.randn(100,1)
self.dataLoc = pylab.randn(100,1)
self.plot_dataMono = self.axesMono.plot(
self.dataMono,
linewidth=1,
color=(1, 1, 0),
)[0]
self.plot_dataBi = self.axesBi.plot(
self.dataBi,
linewidth=1,
color=(1, 1, 0),
)[0]
self.plot_dataLoc = self.axesLoc.plot(
self.dataLoc,
linewidth=1,
color=(1, 1, 0),
)[0]
self.toolbar = NavigationToolbar(self.canvas)
self.vbox = wx.BoxSizer(wx.VERTICAL)
self.vbox.Add(self.canvas, 1, wx.LEFT | wx.TOP | wx.GROW)
self.vbox.AddSpacer(10)
self.hbox = wx.BoxSizer(wx.HORIZONTAL)
flags = wx.ALIGN_LEFT | wx.ALL | wx.ALIGN_CENTER_VERTICAL
self.panel.SetSizer(self.vbox)
self.vbox.Fit(self)
def init_plot(self):
rectSubplotMono = .1, .55, .4, .4
self.axesMono = self.figSignals.add_axes(rectSubplotMono)
rectSubplotBi = .1, .05, .4, .4
self.axesBi = self.figSignals.add_axes(rectSubplotBi)
rectSubplotLoc = .55, .05, .4, .9
self.axesLoc = self.figSignals.add_axes(rectSubplotLoc)
self.axesMono.set_axis_bgcolor('white')
self.axesBi.set_axis_bgcolor('white')
self.axesLoc.set_axis_bgcolor('white')
self.axesMono.set_title('Raw Ultrasound Signal', size=12)
pylab.setp(self.axesMono.get_xticklabels(), fontsize=8)
pylab.setp(self.axesMono.get_yticklabels(), fontsize=8)
pylab.setp(self.axesBi.get_xticklabels(), fontsize=8)
pylab.setp(self.axesBi.get_yticklabels(), fontsize=8)
pylab.setp(self.axesLoc.get_xticklabels(), fontsize=8)
pylab.setp(self.axesLoc.get_yticklabels(), fontsize=8)
def on_redraw_timer(self, event):
self.draw_plot()
def draw_plot(self):
self.axesMono.clear()
self.axesBi.clear()
self.axesLoc.clear()
i = np.arange(1,100)
w = i;
x = pylab.randn(100,1);
y = pylab.randn(100, 1);
z = pylab.randn(100, 1);
# self.axesMono.set_xdata(np.arange(len(x)))
# self.axesMono.set_ydata(np.array(x))
self.axesMono.plot(x, 'red')
self.axesBi.plot(x,'yellow')
self.axesLoc.plot(x, z, 'black')
self.canvas.draw()
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_exit(self, event):
self.Destroy()
if __name__ == '__main__':
app = wx.PySimpleApp()
app.frame = UltrasoundDemoGUI()
app.frame.Show()
app.frame.draw_plot()
app.MainLoop()
del app
I appear to be limited to a refresh rate of approximate 3Hz. Ideally I'd like to visualize the data at a frame rate of 10Hz or higher. Does anyone have any idea how I can efficiently (quickly) update the plots using the axes object?
Thanks for your help, -B
