如何在 Qt4 小部件中显示 Line2D

Question

我想在 Qt4 小部件中显示 Line2D 实例。但是当我运行代码时，它只是显示一个空白图。

这是我的代码。

import sys
from PyQt4 import QtGui
import numpy as np
from matplotlib.figure import Figure
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas

from matplotlib.lines import Line2D

class Qt4MplCanvas(FigureCanvas):
    """Class to represent the FigureCanvas widget"""
    def __init__(self, parent):
        # plot definition
        self.fig = Figure()
        self.axes = self.fig.add_subplot(111)

        x = [1,1]
        y=[2,2]
        self.line = Line2D(x, y, marker = 'o', markerfacecolor = 'r', animated = True)
        self.axes.add_line(self.line)
        self.axes.set_xlim((0,3))
        self.axes.set_ylim((0,3))



        # initialization of the canvas
        FigureCanvas.__init__(self, self.fig)
        # set the parent widget
        self.setParent(parent)

        # we define the widget as expandable
        FigureCanvas.setSizePolicy(self,
                               QtGui.QSizePolicy.Expanding,
                               QtGui.QSizePolicy.Expanding)
        # notify the system of updated policy
        FigureCanvas.updateGeometry(self)

class ApplicationWindow(QtGui.QMainWindow):
    """Example main window"""
    def __init__(self):
        # initialization of Qt MainWindow widget
        QtGui.QMainWindow.__init__(self)
        # set window title
        self.setWindowTitle("Matplotlib Figure in a Qt4 Window With NavigationToolbar")

        # instantiate a widget, it will be the main one
        self.main_widget = QtGui.QWidget(self)

        # create a vertical box layout widget
        vbl = QtGui.QVBoxLayout(self.main_widget)
        # instantiate our Matplotlib canvas widget
        qmc = Qt4MplCanvas(self.main_widget)
        # instantiate the navigation toolbar
        vbl.addWidget(qmc)
        # set the focus on the main widget
        self.main_widget.setFocus()
        # set the central widget of MainWindow to main_widget
        self.setCentralWidget(self.main_widget)


# create the GUI application
qApp = QtGui.QApplication(sys.argv)
# instantiate the ApplicationWindow widget
aw = ApplicationWindow()
# show the widget
aw.show()
# start the Qt main loop execution, exiting from this script
# with the same return code of Qt application
sys.exit(qApp.exec_())

我的代码中有两个类。 Qt4MplCanvas 类用于绘制 Line2D 图形。类 ApplicationWindow 是写一个窗口并在其上添加一个小部件。

Answer 1

看来问题出在一线（但不幸的是我不知道为什么......）：

self.line = Line2D(x, y, marker = 'o', markerfacecolor = 'r', animated = True)

我通过删除animated = True 看到了一个情节。这将行更改为：

self.line = Line2D(x, y, marker = 'o', markerfacecolor = 'r')

这显示了一个坐标为 (1,2) 的点。

我不知道情节是否应该随着时间的推移而改变，但也许这个example 可以帮助你。