How to adjust the size of a plot in PyQt?

Question

I have the following code which I found here. I reduced the code a bit to make it more suitable to my question.

import sys
import matplotlib
matplotlib.use("Qt5Agg")
from PyQt5 import QtCore
from PyQt5.QtCore import pyqtSlot, pyqtSignal, QObject
from PyQt5.QtWidgets import *
from numpy import arange, sin, pi
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure

class MyMplCanvas(FigureCanvas):
    """Ultimately, this is a QWidget (as well as a FigureCanvasAgg, etc.)."""
    def __init__(self, parent=None, width = 5, height = 3, dpi=100):

        fig = Figure(figsize=(width, height), dpi=dpi)
        self.axes = fig.add_subplot(111)

        self.compute_initial_figure()
        FigureCanvas.__init__(self, fig)
        self.setParent(parent)

        FigureCanvas.updateGeometry(self)

class MyStaticMplCanvas(MyMplCanvas):
    """Simple canvas with a sine plot."""
    def compute_initial_figure(self):
        t = arange(0.0, 3.0, 0.01)
        s = sin(2*pi*t)
        self.axes.plot(t, s)
        self.axes.set_ylabel('label2')
        self.axes.set_xlabel('label1')
        self.axes.grid(True)

class ApplicationWindow(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)

        self.setMinimumWidth(800)
        self.setMinimumHeight(300)
        self.setMaximumWidth(800)
        self.setMaximumHeight(300)

        self.main_widget = QWidget(self)

        self.sc = MyStaticMplCanvas(self.main_widget, width=5, height=4, dpi=100)

        l = QVBoxLayout(self.main_widget)
        l.addWidget(self.sc)
        self.setCentralWidget(self.main_widget)

if __name__ == '__main__':
    app = QApplication(sys.argv)

    aw = ApplicationWindow()
    aw.setWindowTitle("PyQt5 Matplotlib Example")
    aw.show()
    app.exec_()

The problem is that the plot is shown in principle correctly but the x-label is missing (fell out of the frame which is displayed). So, how can I adjust the size of the axes object to make PyQt also display the x-label?

I know that the figure size is adjustable through the 'figsize' argument. But so far I could not find a similar command for a diagram inside of the figure.

Also, I heard of the gridspec package of matplotlib but I think it is not suitable here since I only have one plot to display.

There are two things getting mixed here. You have an axes with ticklabels and an xlabel. This sits inside a figure. The figure is embedded in PyQt. Do you want to change the figure to fit the dimension of the PyQt widget or do you want to change the axes to fit inside the figure? — ImportanceOfBeingErnest, Jun 03 '17 at 17:28
The latter one, so to change the axes to fit inside the figure — Tho Re, Jun 04 '17 at 08:35

score 4 · Answer 1 · answered Jun 04 '17 at 13:40

You may want to read the thight layout guide.

So one option is to call

self.fig.tight_layout()

You can also adjust the subplot parameters

self.fig.subplots_adjust(0.2, 0.2, 0.8, 0.8) # left,bottom,right,top

You can also set the position of the axes

self.axes.set_position([0.2, 0.2, 0.6, 0.6]) # left,bottom,width,height

score 1 · Answer 2 · answered Jun 04 '17 at 08:58

1

I solved the problem and it turned out that one can simply adjust the axes through the position argument.

self.ax = self.fig.add_subplot(111, position=[0.15, 0.15, 0.75, 0.75])

answered Jun 04 '17 at 08:58

Tho Re

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How to adjust the size of a plot in PyQt?

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