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1. efiring commented on Jun 29, 2017

   

   efiring

   on Jun 29, 2017

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   I would call it a shortcoming of the twinx implementation: it makes a second Axes at the same position as the first, but it has no mechanism for ensuring that if the position of either is subsequently changed, the position of the other is also changed to match it. Ideally, the position of both Axes would be the same object so that it would not be necessary to use callbacks to keep them synchronized. There are several attributes related to position, so I'm not sure whether this would be a simple change, a difficult one, or a complete can of worms.
2. tacaswell

   added this to the This milestone has been deleted milestone on Jun 30, 2017
3. jklymak commented on Dec 11, 2017

   

   jklymak

   on Dec 11, 2017

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   #9082 addresses this (though you can't use the pyplot interface)

   data = np.random.random((64, 128)) * 2.0
   x = np.arange(128)
   y = np.arange(64)
   fig, ax = plt.subplots(constrained_layout=True)
   pcm = ax.pcolormesh(x, y, data)
   
   #plt.colorbar() --> here it works fine
   ax2 = ax.twinx()
   fig.colorbar(pcm)
   # --> here it gives wrong x values for the orange plot
   
   ax2.plot(x, np.sin(x/10), color="orange", lw=4)
   
   plt.show()

   
4. PrometheusPi commented on Dec 12, 2017

   

   PrometheusPi

   on Dec 12, 2017

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   @jklymak Thanks for posting this. I will cherry pick your pull request.
5. efiring commented on Jan 21, 2018

   

   efiring

   on Jan 21, 2018

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   This is also addressed by #10033.

   Reacted by Jody Klymak
6. efiring commented on Jan 26, 2018

   

   efiring

   on Jan 26, 2018

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   Closed by #10033.
7. efiring

   closed this as completedon Jan 26, 2018
8. QuLogic

   modified the milestones: This milestone has been deleted, v2.2.0 on Feb 12, 2018
9. bactone commented on Nov 24, 2021

   

   bactone

   on Nov 24, 2021

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   while I got the same problem, here is my code: if a twinx exist, then if you remove the colorbar, and the axe shrink, even if you apply tight layout, it won't recover.

   import sys
   import numpy as np
   from PyQt5 import QtWidgets
   
   import matplotlib
   from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
   from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar
   import matplotlib.pyplot as plt
   
   
   matplotlib.use("Qt5Agg")
   
   
   class MplCanvas(FigureCanvasQTAgg):
       def __init__(self, parent=None, width=5, height=4, dpi=100):
           self.fig = plt.figure(figsize=(width, height), dpi=dpi)
           self.axe = self.fig.add_subplot(1, 1, 1, label='good')
           super().__init__(self.fig)
   
   
   class MainWindow(QtWidgets.QMainWindow):
       def __init__(self):
           super().__init__()
   
           v_layout = QtWidgets.QVBoxLayout()
   
           self.canvas = MplCanvas(self, width=5, height=4, dpi=100)
           self.axe = self.canvas.axe
           self.figure = self.canvas.fig
           
           # draw a scatter plot on self.axe
           np.random.seed(19680801)
           rx, ry = 3., 1.
           area = rx * ry * np.pi
           theta = np.arange(0, 2 * np.pi + 0.01, 0.1)
           verts = np.column_stack([rx / area * np.cos(theta), ry / area * np.sin(theta)])
           x, y, s, c = np.random.rand(4, 30)
           s *= 10 ** 2
           self.image = self.axe.scatter(x, y, s=s, c=c, marker=verts)
   
           # add a twinx: it fails the tight layout*********************
           x = np.arange(0, 1, 0.01)
           y = np.random.randn(len(x))
           self.ax2 = self.axe.twinx()
           self.ax2.plot(x, y, lw=2, linestyle='-', label='signal')
           # ***********************************************************
   
           toolbar = NavigationToolbar(self.canvas, self)
           v_layout.addWidget(toolbar)
   
           v_layout.addWidget(self.canvas)
           label = QtWidgets.QLabel('Show Color Bar')
           self.checkBox_colorBar = QtWidgets.QCheckBox(self)
           h_layout = QtWidgets.QHBoxLayout(self)
           h_layout.addWidget(label)
           h_layout.addWidget(self.checkBox_colorBar)
   
           v_layout.addLayout(h_layout)
   
           widget = QtWidgets.QWidget()
           widget.setLayout(v_layout)
           self.setCentralWidget(widget)
   
           self.checkBox_colorBar.toggled.connect(self.showColorBar)
   
       def showColorBar(self):
   
           color_bar = self.image.colorbar  # None if no color bar
   
           if self.checkBox_colorBar.isChecked():
               if color_bar is None:
                   self.figure.colorbar(self.image)
           else:
               if color_bar is not None:
                   color_bar.remove()
                   del color_bar
   
           self.canvas.draw()
   
   
   if __name__ == '__main__':
   
       app = QtWidgets.QApplication(sys.argv)
   
       window = MainWindow()
       mw = window
       mw.show()
       app.exec_()

   it gives out the following result if toggle the show color bar check box a few times.
   
   
   
   
10. jklymak commented on Nov 24, 2021

    

    jklymak

    on Nov 24, 2021

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    Please open a new bug report including all relevant version info. However I do not think removing a Colorbar will magically reallocate its space using tight_layout. It may work with constrained_layout