[英]How can I update a matplotlib figure in a way that prevents xdata from being None?
我正在編寫一個應用程序,該應用程序定期(大約每秒一次)從硬件設備收集一些數據,並使用matplotlib將其顯示在圖形中。 用戶將定期單擊圖形,當發生這種情況時,我需要知道圖形的坐標系中測量的單擊的x和y坐標。
這很容易做到:如果canvas
是FigureCanvas
實例,則可以說
canvas.mpl_connect('button_release_event', mouse_up_handler)
並定義
def mouse_up_handler(event):
print('The user clicked at ({}, {})'.format(event.xdata, event.ydata))
以在圖形的坐標系中顯示點擊坐標。 但是,有時用戶會在圖形更新時單擊鼠標右鍵,然后event.xdata
和.ydata
為None
。 現在,我只是舍棄這些點擊,但是當應用程序忽略他們的點擊時,這顯然讓用戶感到沮喪。
我已經附上了完整的示例程序,以便您可以看到如何用新的圖形替換當前的圖形。 (如果運行它並重復單擊圖形,您有時會看到報告的x坐標有時為None
。)我可以用永遠不會給出None
的方式替換圖形的數據嗎? 我只希望一次顯示一組數據。
from __future__ import print_function
from math import exp
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg \
as FigureCanvas
from matplotlib.figure import Figure
from random import normalvariate
from threading import Timer
from time import sleep
import wx
class GraphView(wx.Panel):
def __init__(self, parent):
wx.Panel.__init__(self, parent)
self.figure = Figure()
canvas = FigureCanvas(self, -1, self.figure)
canvas.mpl_connect('button_release_event', self.mouse_up_handler)
self.axes = None
sizer = wx.BoxSizer(wx.VERTICAL)
sizer.Add(canvas, 1, wx.GROW)
self.SetSizer(sizer)
self.generate_new_data()
def generate_new_data(self):
x_values = range(16384)
y_values = [exp(normalvariate(0, 10)) for _ in range(16384)]
if self.axes is not None:
self.figure.delaxes(self.axes)
sleep(0.4) # simulate some additional work being done with the data
self.axes = self.figure.add_subplot(1, 1, 1)
self.axes.set_yscale('log')
self.axes.autoscale(enable=True)
self.axes.set_xlim(x_values[0], x_values[-1])
self.axes.plot(x_values, y_values, antialiased=False)
self.figure.canvas.draw()
Timer(1.0, self.generate_new_data).start()
def mouse_up_handler(self, event):
print('Click at x = {}'.format(event.xdata))
class GraphWindow(wx.Frame):
def __init__(self, parent):
wx.Frame.__init__(self, parent)
graph_view = GraphView(self)
if __name__ == '__main__':
app = wx.App(False)
GraphWindow(None).Show()
app.MainLoop()
就像是:
def __init__(self, parent):
wx.Panel.__init__(self, parent)
self.figure = Figure()
canvas = FigureCanvas(self, -1, self.figure)
canvas.mpl_connect('button_release_event', self.mouse_up_handler)
# make axes
self.ax = self.figure.add_subplot(1, 1, 1)
# set up details
self.ax.set_yscale('log')
self.ax.autoscale(enable=True)
self.ax.set_xlim(x_values[0], x_values[-1])
# make the line
self.ln, = self.ax.plot([], []) # add what ever parameters you want
sizer = wx.BoxSizer(wx.VERTICAL)
sizer.Add(canvas, 1, wx.GROW)
self.SetSizer(sizer)
self.generate_new_data()
def generate_new_data(self):
x_values = range(16384)
y_values = [exp(normalvariate(0, 10)) for _ in range(16384)]
sleep(0.4) # simulate some additional work being done with the data
# update your existing line
self.ln.set_data(x_values, y_values, antialiased=False)
self.figure.canvas.draw()
Timer(1.0, self.generate_new_data).start()
重用軸和Line2D
對象。
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