设置图形大小（mpl）不影响画布和布局答案

【问题标题】：set figure size (mpl) is not influence canvas and layout设置图形大小（mpl）不影响画布和布局
【发布时间】：2018-08-16 19:51:35
【问题描述】：

我正在尝试将小部件大小调整为图形大小。由于某种原因，画布和小部件的大小没有改变。我尝试设置容器小部件和画布的 SizePolicy，结果相同。

import sys
import matplotlib.pyplot as plt
from PyQt4 import QtGui

class CanvasOnWidget(QtGui.QWidget):

    def __init__(self):
        QtGui.QWidget.__init__(self)
        self._layout = QtGui.QVBoxLayout(self)
        self._fig = plt.figure()
        self._layout.addWidget(self._fig.canvas)
        plt.plot(range(10),range(10))
        self._fig.canvas.mpl_connect('button_press_event', self._resize)

    def _resize(self, event):
        w,h = self._fig.get_size_inches()
        if event.button == 1: # left click
            h-=1
        elif event.button == 3: # right click
            h+=1
        self._fig.set_size_inches(w, h, forward=True)
        self._fig.canvas.draw()
        self._fig.canvas.flush_events()
        print self.size()
        print self._fig.canvas.size()
        print self._fig.get_size_inches()

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    main = CanvasOnWidget()
    main.show()
    sys.exit(app.exec_())

【问题讨论】：

标签： python user-interface matplotlib pyqt4

【解决方案1】：

我想您需要通知小部件您希望更改其大小。这可以使用.resize 来完成。由于画布周围有边框，因此在设置新的小部件大小时需要考虑此边框。

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


class CanvasOnWidget(QtGui.QWidget):

    def __init__(self):
        QtGui.QWidget.__init__(self)

        self._layout = QtGui.QVBoxLayout(self)
        self.setLayout(self._layout)
        self._fig = Figure()
        self.canv = FigureCanvas(self._fig)
        self._layout.addWidget(self.canv)

        ax = self._fig.add_subplot(111)
        ax.plot(range(10),range(10))
        self._fig.canvas.mpl_connect('button_press_event', self._resize)

    def _resize(self, event):
        w,h = self._fig.get_size_inches()
        dw = self.size().width()-w*self._fig.dpi
        dh = self.size().height()-h*self._fig.dpi
        if event.button == 1: # left click
            h-=1
        elif event.button == 3: # right click
            h+=1
        self._fig.set_size_inches(w, h, forward=True)

        self._fig.canvas.draw_idle()
        self.resize(w*100+dw,h*100+dh)

        print self.size()
        print self._fig.canvas.size()
        print self._fig.get_size_inches()

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    main = CanvasOnWidget()
    main.show()
    sys.exit(app.exec_())

请注意，为了将Figure 放入FigureCanvasQT，我已更改为代码。在 Qt GUI 中使用 pyplot 会导致问题。

但是，如果你想使用pyplot，整个代码可以简化很多。

import matplotlib.pyplot as plt

class Plot():

    def __init__(self):
        self._fig = plt.figure()
        ax = self._fig.add_subplot(111)
        ax.plot(range(10),range(10))
        self._fig.canvas.mpl_connect('button_press_event', self._resize)

    def _resize(self, event):
        w,h = self._fig.get_size_inches()
        if event.button == 1: # left click
            h-=1
        elif event.button == 3: # right click
            h+=1
        self._fig.set_size_inches(w, h, forward=True)

        self._fig.canvas.draw_idle()
        print self._fig.get_size_inches()

if __name__ == '__main__':
    app = Plot()
    plt.show()

【讨论】：