rcparams not being applied to custom matplotlib class

Question

I am trying to write a custom figure class around matplotlib.figure.Figure which among other things, automatically applies the correct formatting. Here's the current configuration:

import matplotlib
from matplotlib.axes import Axes
from matplotlib.figure import Figure
from matplotlib.backends.backend_qtagg import FigureCanvasQTAgg as Canvas

class CustomFigure(Figure):
    def __init__(self, figsize: tuple, layout: str):
        super().__init__(figsize=figsize, layout=layout)
        self.canvas = Canvas(self)
        matplotlib.use("QtAgg")
        self.set_common_params()
        
        
    def generate_axes(self, num_axes: int, layout: tuple = None) -> Axes:
        if layout is None:
            layout = (1, num_axes)
        return self.subplots(*layout)
    
        
    def set_common_params(self):
        matplotlib.rcParams["figure.titlesize"] = 45
        matplotlib.rcParams["axes.titlesize"]   = 13
        matplotlib.rcParams["axes.labelsize"]   = 12
        matplotlib.rcParams["axes.linewidth"]   = 1.5
        matplotlib.rcParams["xtick.labelsize"]  = 11
        matplotlib.rcParams["ytick.labelsize"]  = 11
        
    
    @staticmethod
    def set_labels(ax: Axes, xlabel: str, ylabel: str, title: str = None):
        ax.set_xlabel(xlabel)
        ax.set_ylabel(ylabel)
        if title is not None:
            ax.set_title(title)
            
    
    def generate_pdf(self, filename: str):
        self.savefig(f"{filename}.pdf")
        
        


if __name__ == "__main__":
    import sys
    from PySide6.QtWidgets import QApplication, QMainWindow
    app = QApplication(sys.argv)
    win = QMainWindow()
    fig = CustomFigure((5,5), "tight")
    fig.set_labels(fig.generate_axes(1), "X", "Y", "Title")
    win.setCentralWidget(fig.canvas)
    win.show()
    sys.exit(app.exec())

I've tried putting the rcParams in every possible location of the code, even before the class definition, but nothing works.

How do I get the rcParams applied properly?

Answer 1

If I understood your question correctly, your code does set the params as needed except for the figure title. That is because you are using a subplot which has 'suptitle'. So the parameter you set for figure.titlesize will not work! Check this instead:

import matplotlib
from matplotlib.axes import Axes
from matplotlib.figure import Figure
from matplotlib.backends.backend_qtagg import FigureCanvasQTAgg as Canvas
import matplotlib.pyplot as plt


class CustomFigure(Figure):
    def __init__(self, figsize: tuple, layout: str):
        super().__init__(figsize=figsize, layout=layout)
        self.canvas = Canvas(self)
        matplotlib.use("QtAgg")
        self.set_common_params()

    def generate_axes(self, num_axes: int, layout: tuple = None) -> Axes:
        if layout is None:
            layout = (1, num_axes)
        return self.subplots(*layout)

    def set_common_params(self):
        matplotlib.rcParams["figure.titlesize"] = 'large'  # this will not work since it is not for a subplot
        matplotlib.rcParams["axes.titlesize"] = 45
        matplotlib.rcParams["axes.labelsize"] = 45
        matplotlib.rcParams["axes.linewidth"] = 1.5
        matplotlib.rcParams["xtick.labelsize"] = 10
        matplotlib.rcParams["ytick.labelsize"] = 10
        matplotlib.rcParams["font.sans-serif"] = "Verdana"

    @staticmethod
    def set_labels(ax: Axes, xlabel: str, ylabel: str, title: str = None):
        ax.set_xlabel(xlabel)
        ax.set_ylabel(ylabel)
        if title is not None:
            ax.set_title(title)

    def generate_pdf(self, filename: str):
        self.savefig(filename)

    def clearfig(self):
        self.clf()


if __name__ == "__main__":
    import sys
    from PySide6.QtWidgets import QApplication, QMainWindow

    app = QApplication(sys.argv)
    win = QMainWindow()
    fig = CustomFigure((5, 5), "tight")
    fig.set_labels(fig.generate_axes(1), "X", "Y", "Title")
    win.setCentralWidget(fig.canvas)
    win.show()
    sys.exit(app.exec())