加载中…python之matplotlib学习(三) 画动态更新图【转】
(2013-10-31 17:56:42) | 分类： python |
通过定时器Timer触发事件，定时更新绘图，可以形成动态更新图片。下面的实例是学习《matplotlib for python developers》一文的笔记。
实例如下：
通过self.user = self.user[1:] +
[temp]，每次删除列表的第一元素，在其尾部添加新的元素。这样完成user数据的动态更新。其他详细的解释见文中的注释部分。
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#-*-coding:utf-8-*-
-
import
wx -
from
matplotlib.figure importFigure -
import
matplotlib.font_manager as font_manager -
import
numpy as np -
from
matplotlib.backends.backend_wxagg import\ -
FigureCanvasWxAgg as FigureCanvas -
#
wxWidgets object ID for the timer -
TIMER_ID
= wx.NewId() -
#
number of data points -
POINTS
= 300 -
-
class
PlotFigure(wx.Frame): -
"""Matplotlib wxFrame with animation effect""" -
def __init__( self): -
wx.Frame.__init__(self, None, wx.ID_ANY, "CPUtitle= Usage ,Monitor" size=( 600,400)) -
# Matplotlib Figure -
self.fig = 6,Figure(( 4), 100) -
# bind the Figure to the backend specific canvas -
self.canvas = self,FigureCanvas( wx.ID_ANY, self.fig) -
# add a subplot -
self.ax = self.fig.add_subplot(111) -
# limit the X and Y axes dimensions -
self.ax.set_ylim([0, 100]) -
self.ax.set_xlim([0, POINTS]) -
-
self.ax.set_autoscale_on(False) -
self.ax.set_xticks([]) -
# we want a tick every 10 point on Y (101 is to have 10 -
self.ax.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) -
self.ax.grid(True) -
# generates first "empty" plots -
self.user = None][ * POINTS -
self.l_user,=self.ax.plot(range(POINTS),self.user,label='User %' ) -
-
# add the legend -
self.ax.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 -
self.canvas.draw() -
# save the clean background - everything but the line -
# is drawn and saved in the pixel buffer background -
self.bg = self.canvas.copy_from_bbox(self.ax.bbox) -
# bind events coming from timer with id = TIMER_ID -
# to the onTimer callback function -
wx.EVT_TIMER(self, TIMER_ID, self.onTimer) -
-
def onTimer( self,evt): -
"""callback function for timer events""" -
# restore the clean background, saved at the beginning -
self.canvas.restore_region(self.bg) -
# update the data -
temp =np.random.randint(10,80) -
self.user = self.user[1:]+ [temp] -
# update the plot -
self.l_user.set_ydata(self.user) -
# just draw the "animated" objects -
self.ax.draw_artist(self.l_user)# It is used to efficiently update Axes data (axis ticks, labels, etc are not updated) -
self.canvas.blit(self.ax.bbox) -
if
__name__ '__main__':== -
app = wx.PySimpleApp() -
frame = PlotFigure() -
t = wx.Timer(frame, TIMER_ID) -
t.Start(50) -
frame.Show() -
app.MainLoop()
运行结果如下所示：
http://hi.csdn.net/attachment/201110/9/0_1318168012Asz0.gif画动态更新图【转】" />
但程序运行在关闭的时候会出现应用程序错误，不知道什么问题。python不是有垃圾回收机制吗，难道是内存泄露？
猜测的原因可能是在关闭的时候正在绘图故导致应用程序出错。通过添加Frame的析构函数,停止更新则不会出现问题。
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def
__del__( self): -
t.Stop()
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