在 pyqt5 小部件中更新 matplotlib

Question

我在 qt 设计器中创建了一个 UI，并使用 UIC 加载它。 我对 UI 进行了更新，所以我不想将 UI 转换为 python。 我正在使用以下帖子嵌入我的 PLT： Embed a matplotlib plot in a pyqt5 gui

但是，我尝试更新图表并使用以下不同方法失败：

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
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    <y>0</y>
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    <height>429</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <widget class="QWidget" name="graphWidget" native="true">
    <property name="geometry">
     <rect>
      <x>10</x>
      <y>10</y>
      <width>551</width>
      <height>351</height>
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          <red>255</red>
          <green>255</green>
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          <red>255</red>
          <green>255</green>
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       <colorrole role="Dark">
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          <red>255</red>
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       <colorrole role="Shadow">
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          <green>255</green>
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      <inactive>
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          <red>0</red>
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       <colorrole role="Button">
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          <red>255</red>
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       <colorrole role="Light">
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          <red>255</red>
          <green>255</green>
          <blue>255</blue>
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       </colorrole>
       <colorrole role="Midlight">
        <brush brushstyle="SolidPattern">
         <color alpha="255">
          <red>255</red>
          <green>255</green>
          <blue>255</blue>
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       <colorrole role="Dark">
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         <color alpha="255">
          <red>127</red>
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          <blue>127</blue>
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          <red>255</red>
          <green>255</green>
          <blue>255</blue>
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       <colorrole role="Window">
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         <color alpha="255">
          <red>255</red>
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         <color alpha="255">
          <red>255</red>
          <green>255</green>
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         <color alpha="255">
          <red>255</red>
          <green>255</green>
          <blue>255</blue>
         </color>
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       </colorrole>
       <colorrole role="Midlight">
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         <color alpha="255">
          <red>255</red>
          <green>255</green>
          <blue>255</blue>
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       </colorrole>
       <colorrole role="Dark">
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         <color alpha="255">
          <red>127</red>
          <green>127</green>
          <blue>127</blue>
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          <red>127</red>
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          <blue>127</blue>
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        <brush brushstyle="SolidPattern">
         <color alpha="255">
          <red>255</red>
          <green>255</green>
          <blue>255</blue>
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         <color alpha="255">
          <red>255</red>
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          <blue>255</blue>
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         <color alpha="255">
          <red>255</red>
          <green>255</green>
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       <colorrole role="AlternateBase">
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         <color alpha="255">
          <red>255</red>
          <green>255</green>
          <blue>255</blue>
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         <color alpha="255">
          <red>255</red>
          <green>255</green>
          <blue>220</blue>
         </color>
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       </colorrole>
       <colorrole role="ToolTipText">
        <brush brushstyle="SolidPattern">
         <color alpha="255">
          <red>0</red>
          <green>0</green>
          <blue>0</blue>
         </color>
        </brush>
       </colorrole>
       <colorrole role="PlaceholderText">
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         <color alpha="128">
          <red>0</red>
          <green>0</green>
          <blue>0</blue>
         </color>
        </brush>
       </colorrole>
      </disabled>
     </palette>
    </property>
    <property name="autoFillBackground">
     <bool>true</bool>
    </property>
   </widget>
   <widget class="QPushButton" name="start">
    <property name="geometry">
     <rect>
      <x>590</x>
      <y>30</y>
      <width>91</width>
      <height>41</height>
     </rect>
    </property>
    <property name="text">
     <string>Start</string>
    </property>
   </widget>
   <widget class="QPushButton" name="restart">
    <property name="enabled">
     <bool>false</bool>
    </property>
    <property name="geometry">
     <rect>
      <x>590</x>
      <y>100</y>
      <width>91</width>
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    </property>
    <property name="text">
     <string>Restart</string>
    </property>
    <property name="checkable">
     <bool>true</bool>
    </property>
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   <widget class="QLabel" name="label_7">
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      <y>130</y>
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      <height>71</height>
     </rect>
    </property>
    <property name="text">
     <string/>
    </property>
    <property name="alignment">
     <set>Qt::AlignLeading|Qt::AlignLeft|Qt::AlignTop</set>
    </property>
    <property name="wordWrap">
     <bool>true</bool>
    </property>
   </widget>
   <widget class="QPushButton" name="intervene">
    <property name="enabled">
     <bool>true</bool>
    </property>
    <property name="geometry">
     <rect>
      <x>590</x>
      <y>170</y>
      <width>91</width>
      <height>41</height>
     </rect>
    </property>
    <property name="text">
     <string>Intervene</string>
    </property>
    <property name="checkable">
     <bool>false</bool>
    </property>
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  <widget class="QMenuBar" name="menubar">
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     <y>0</y>
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     <height>21</height>
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   </property>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
 </widget>
 <resources/>
 <connections/>
</ui>

from PyQt5 import QtCore, QtWidgets, uic
import pyqtgraph as pg
import sys  # We need sys so that we can pass argv to QApplication
import time
import matplotlib
import matplotlib.pylab as plt
from matplotlib.backends.backend_qt5agg import FigureCanvas
from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar
import numpy as np
from scipy.spatial import Voronoi, voronoi_plot_2d

matplotlib.use('QT5Agg')


class MainWindow(QtWidgets.QMainWindow):

    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        # Load the UI
        uic.loadUi('src\Main.ui', self)

        # Runs functions on button press
        self.start.clicked.connect(self.startfcn)

        # add toolbar
        # self.addToolBar(QtCore.Qt.BottomToolBarArea, NavigationToolbar(self.canvas, self))
    # This function is run when the start button is pushed
    def startfcn(self):
        sd = 20
        # rng(sd)
        numIterations = 1000
        samplingPeriod = 10
        xrange = 10  # region size
        yrange = 5
        n = 20  # number of robots (changing the number of robots is interesting)
        dt = 1
        maxSpeed = 8

        # Draw graph
        points = np.random.rand(10, 2)  # random points for Voronoi
        vor = Voronoi(points)  # Create Voronoi object
        fig = voronoi_plot_2d(vor)  # Make vor object into a plot object
        canvas = FigureCanvas(fig)  # create a mpl canvas obj
        lay = QtWidgets.QVBoxLayout(self.graphWidget)  # create layout in graph widget
        lay.setContentsMargins(0, 0, 0, 0)
        lay.addWidget(canvas)  # add canvas obj to layout
        # all of these are attempts to update the graph
        canvas.draw()
        self.graphWidget.update()
        self.graphWidget.show()
        QtWidgets.QApplication.processEvents()


def main():
    app = QtWidgets.QApplication(sys.argv)
    main = MainWindow()
    main.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

按下开始按钮时，它应该显示一个新的随机 voronoi plot，但它没有。

每次按下开始按钮时，我都需要它来更新 graphWidget。

Answer 1

如果要更改Figure ，则必须创建一个新的 canvas，因此您必须销毁前一个：

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        self.canvas = None

        uic.loadUi("Main.ui", self)
        self.canvas_layout = QtWidgets.QVBoxLayout(self.graphWidget)
        self.canvas_layout.setContentsMargins(0, 0, 0, 0)

        self.start.clicked.connect(self.startfcn)

        # add toolbar
        # self.addToolBar(QtCore.Qt.BottomToolBarArea, NavigationToolbar(self.canvas, self))

    # This function is run when the start button is pushed
    def startfcn(self):
        # Draw graph
        points = np.random.rand(10, 2)  # random points for Voronoi
        vor = Voronoi(points)  # Create Voronoi object
        fig = voronoi_plot_2d(vor)  # Make vor object into a plot object

        if self.canvas is not None:
            self.canvas.deleteLater()

        self.canvas = FigureCanvas(fig)

        self.canvas_layout.addWidget(self.canvas)

另一个更好的选择是通过“ax”参数将轴传递给voronoi_plot_2d()方法：

import sys

from PyQt5 import QtCore, QtWidgets, uic

import matplotlib
from matplotlib.figure import Figure
from matplotlib.backends.backend_qt5agg import FigureCanvas
from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar

import numpy as np

from scipy.spatial import Voronoi, voronoi_plot_2d

matplotlib.use("QT5Agg")


class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        self.canvas = FigureCanvas(Figure())

        uic.loadUi("Main.ui", self)
        lay = QtWidgets.QVBoxLayout(self.graphWidget)
        lay.setContentsMargins(0, 0, 0, 0)
        lay.addWidget(self.canvas)

        self.start.clicked.connect(self.startfcn)

        self.ax = None

        # add toolbar
        # self.addToolBar(QtCore.Qt.BottomToolBarArea, NavigationToolbar(self.canvas, self))

    # This function is run when the start button is pushed
    def startfcn(self):
        if self.ax is None:
            self.ax = self.canvas.figure.subplots()
        # Draw graph
        points = np.random.rand(10, 2)  # random points for Voronoi
        vor = Voronoi(points)  # Create Voronoi object
        self.ax.clear()
        voronoi_plot_2d(vor, ax=self.ax)  # Make vor object into a plot object
        self.canvas.draw()


def main():
    app = QtWidgets.QApplication(sys.argv)
    main = MainWindow()
    main.show()
    sys.exit(app.exec_())


if __name__ == "__main__":
    main()