当我将 Qslitter 移动到带有 matplotlib 图形的边缘时，如何避免 PyQt5 崩溃？

Question

我在 QSplitter 中有两个 matplotlib 图。当我将 Splitter 移动到边缘时（图形消失），代码崩溃。

我得到的错误是

Traceback (most recent call last):
  File "C:\Python36\lib\site-packages\matplotlib\backends\backend_qt5.py", line 397, in resizeEvent
    self.figure.set_size_inches(winch, hinch, forward=False)
  File "C:\Python36\lib\site-packages\matplotlib\figure.py", line 902, in set_size_inches
    raise ValueError(f'figure size must be positive finite not {size}')
ValueError: figure size must be positive finite not [0.   6.12]

以前这不是问题，当屏幕上只有 Qsplitter 的两侧之一时，我的代码没有崩溃。当我再次将分离器拉到中间时，图形又正常出现了。

这里是一个最小的例子：

from PyQt5.QtGui import *
from PyQt5.QtWidgets import  *
from PyQt5.QtCore import * 
import sys
import matplotlib.pyplot as plt
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas

class window(QMainWindow):
    def __init__(self, parent=None):
        super(window, self).__init__()
        self.parent = parent

        self.centralWidget = QWidget()
        self.setCentralWidget(self.centralWidget)

        self.mainHBOX_param_scene = QHBoxLayout()

        self.mainsplitter = QSplitter(Qt.Horizontal)
        V1 = Viewer()
        V2 = Viewer()
        self.mainsplitter.addWidget(V1)
        self.mainsplitter.addWidget(V2)


        self.mainHBOX_param_scene.addWidget(self.mainsplitter)
        self.centralWidget.setLayout(self.mainHBOX_param_scene)


class Viewer(QGraphicsView):
    def __init__(self, parent=None):
        super( Viewer, self).__init__(parent)
        self.parent = parent
        self.setStyleSheet("border: 0px")
        self.scene = QGraphicsScene(self)
        self.setScene(self.scene)
        self.figure = plt.figure()
        self.canvas = FigureCanvas(self.figure)

        self.axes_Delay = self.figure.add_subplot(1, 1,1)
        self.axes_Delay.set_title("Title")

        # self.canvas.setGeometry(0, 0, 1600, 500 )
        layout = QVBoxLayout()
        layout.addWidget(self.canvas)
        self.setLayout(layout)
        self.canvas.show()


    def closeEvent(self, event):
        plt.close(self.figure)


def main():
    app = QApplication(sys.argv)
    ex = window(app)
    ex.show()
    sys.exit(app.exec_( ))


if __name__ == '__main__':
    main()

如何避免这个错误？顺便说下我用的是matplotlib 3.2.1版本

Answer 1

很明显，这是一个 matplotlib 错误，它没有考虑到 resizeEvent 的大小可以 <=0，并且该信息用于通过关联的 Figure 进行绘制，从而导致此类错误。解决方法是重写resizeEvent方法：

class FixFigureCanvas(FigureCanvas):
    def resizeEvent(self, event):
        if event.size().width() <= 0 or event.size().height() <= 0:
            return
        super(FixFigureCanvas, self).resizeEvent(event)

# ...
self.figure = plt.figure()
<b>self.canvas = FixFigureCanvas(self.figure)</b>

self.axes_Delay = self.figure.add_subplot(1, 1, 1)
# ...

当我将 Qslitter 移动到带有 matplotlib 图形的边缘时，如何避免 PyQt5 崩溃？

How avoid PyQt5 to crash when I move Qslitter to the edge with a matplotlib figure in it?

python

matplotlib

qsplitter

pyqt5