synopsis
By triggering an event with the timer Timer and updating the drawing at regular intervals, it is possible to form a dynamically updated picture. The following examples are notes from studying the article "matplotlib for python developers".
realization
Implementation code and brief introduction
By = [1:] + [temp], each time the first element of the list is removed, a new element is added to its tail. This completes the dynamic update of the user data. For a more detailed explanation, see the comments section of the text.
#-*-coding:utf-8-*-
import wx
from import Figure
import matplotlib.font_manager as font_manager
import numpy as np
from .backend_wxagg import \
FigureCanvasWxAgg as FigureCanvas
# wxWidgets object ID for the timer
TIMER_ID = ()
# number of data points
POINTS = 300
class PlotFigure():
"""Matplotlib wxFrame with animation effect"""
def __init__(self):
.__init__(self, None, wx.ID_ANY, title="CPU Usage Monitor", size=(600, 400))
# Matplotlib Figure
= Figure((6, 4), 100)
# bind the Figure to the backend specific canvas
= FigureCanvas(self, wx.ID_ANY, )
# add a subplot
= .add_subplot(111)
# limit the X and Y axes dimensions
.set_ylim([0, 100])
.set_xlim([0, POINTS])
.set_autoscale_on(False)
.set_xticks([])
# we want a tick every 10 point on Y (101 is to have 10
.set_yticks(range(0, 101, 10))
# disable autoscale, since we don't want the Axes to ad
# draw a grid (it will be only for Y)
(True)
# generates first "empty" plots
= [None] * POINTS
self.l_user,=(range(POINTS),,label='User %')
# add the legend
(loc='upper center',
ncol=4,
prop=font_manager.FontProperties(size=10))
# force a draw on the canvas()
# trick to show the grid and the legend
()
# save the clean background - everything but the line
# is drawn and saved in the pixel buffer background
= .copy_from_bbox()
# bind events coming from timer with id = TIMER_ID
# to the onTimer callback function
wx.EVT_TIMER(self, TIMER_ID, )
def onTimer(self, evt):
"""callback function for timer events"""
# restore the clean background, saved at the beginning
.restore_region()
# update the data
temp =(10,80)
= [1:] + [temp]
# update the plot
self.l_user.set_ydata()
# just draw the "animated" objects
.draw_artist(self.l_user)# It is used to efficiently update Axes data (axis ticks, labels, etc are not updated)
()
if __name__ == '__main__':
app = ()
frame = PlotFigure()
t = (frame, TIMER_ID)
(50)
()
()
The results of the run are shown below:
question
But the program runs with an application error when it closes, I don't know what the problem is. doesn't python have a garbage collection mechanism, could it be a memory leak?
I guess the reason may be that the application error is caused by the fact that it is drawing when it is closed. By adding a destructor to the Frame and stopping the update, there is no problem.
def __del__( self ): ()
summarize
Above is this article on python of matplotlib learning to draw dynamic update chart example code, I hope you can help. Interested friends can continue to refer to other related topics on this site, if there are inadequacies, welcome to leave a message to point out. Thank you for the support of friends on this site!