Matplotlib运行时动态切换主题样式：直接操作Figure和Axes对象

import matplotlib.pyplot as plt
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
import numpy as np

# 模拟一个MatplotlibWidget类，包含一个画布和数据
class MatplotlibWidget:
    def __init__(self, parent=None):
        self.figure = Figure()
        self.canvas = FigureCanvas(self.figure)
        # 初始创建一个子图
        self.ax = self.figure.add_subplot(111)
        self.canvas.setParent(parent) # 假设有父组件
        self.style = "default" # 初始主题

        # 绘制一些初始数据
        self.plot_initial_data()
        self.apply_default_theme_initial() # 首次应用默认主题

    def plot_initial_data(self):
        x = np.linspace(0, 10, 100)
        y1 = np.sin(x)
        y2 = np.cos(x)
        self.ax.plot(x, y1, label='Sin(x)', color='blue')
        self.ax.plot(x, y2, label='Cos(x)', color='red')
        self.ax.set_xlabel("X-axis")
        self.ax.set_ylabel("Y-axis")
        self.ax.set_title("Dynamic Theme Example")
        self.ax.legend()
        self.canvas.draw()

    def apply_default_theme_initial(self):
        """
        在图表初始化时应用默认主题，类似于plt.style.use('default')的效果
        但这里我们通过直接设置属性来实现，以便后续动态切换时能保持一致
        """
        fig = self.figure
        fig.set_facecolor("white")
        fig.set_edgecolor("lightgray") # 轻微的边框颜色

        ax = self.ax
        ax.set_facecolor("#f0f0f0") # 绘图区域的浅灰色背景
        ax.tick_params(axis='x', colors='black')
        ax.tick_params(axis='y', colors='black')
        ax.xaxis.label.set_color('black')
        ax.yaxis.label.set_color('black')
        ax.title.set_color('black')
        ax.legend().get_frame().set_facecolor('white') # 图例背景
        ax.legend().get_frame().set_edgecolor('black') # 图例边框
        for text in ax.legend().get_texts(): # 图例文字颜色
            text.set_color('black')

        for spine in ax.spines.values():
            spine.set_edgecolor('black') # 轴线颜色

        self.canvas.draw()


    def style_select(self, new_style):
        """
        根据传入的new_style动态切换图表主题
        """
        self.style = new_style
        fig = self.canvas.figure

        if self.style == "dark":
            # 应用深色主题属性
            fig.set_facecolor("#282c34") # 整体背景色
            fig.set_edgecolor("black")

            # 遍历所有Axes对象（通常只有一个）
            for ax in fig.axes:
                ax.set_facecolor("#333333") # 绘图区域背景色
                ax.tick_params(axis='x', colors='white') # 刻度线颜色
                ax.tick_params(axis='y', colors='white')
                ax.xaxis.label.set_color('white') # 轴标签颜色
                ax.yaxis.label.set_color('white')
                ax.title.set_color('white') # 标题颜色
                ax.legend().get_frame().set_facecolor('#444444') # 图例背景
                ax.legend().get_frame().set_edgecolor('white') # 图例边框
                for text in ax.legend().get_texts(): # 图例文字颜色
                    text.set_color('white')

                # 更改轴线颜色
                for spine in ax.spines.values():
                    spine.set_edgecolor('white')

                # 如果有网格线，也需要设置颜色
                ax.grid(True, color='gray', linestyle='--', linewidth=0.5)

        else: # 恢复到默认/浅色主题
            fig.set_facecolor("white")
            fig.set_edgecolor("lightgray")

            for ax in fig.axes:
                ax.set_facecolor("#f0f0f0")
                ax.tick_params(axis='x', colors='black')
                ax.tick_params(axis='y', colors='black')
                ax.xaxis.label.set_color('black')
                ax.yaxis.label.set_color('black')
                ax.title.set_color('black')
                ax.legend().get_frame().set_facecolor('white')
                ax.legend().get_frame().set_edgecolor('black')
                for text in ax.legend().get_texts():
                    text.set_color('black')

                for spine in ax.spines.values():
                    spine.set_edgecolor('black')

                ax.grid(False) # 默认主题可能不显示网格线，或设置为默认颜色

        # 强制重绘画布以显示更改
        self.canvas.draw()

# 这是一个简单的演示如何使用上述MatplotlibWidget
if __name__ == '__main__':
    from PyQt5.QtWidgets import QApplication, QMainWindow, QVBoxLayout, QPushButton, QWidget

    class MainWindow(QMainWindow):
        def __init__(self):
            super().__init__()
            self.setWindowTitle("Matplotlib Dynamic Theme Demo")
            self.setGeometry(100, 100, 800, 600)

            self.central_widget = QWidget()
            self.setCentralWidget(self.central_widget)
            self.layout = QVBoxLayout(self.central_widget)

            self.mpl_widget = MatplotlibWidget(self.central_widget)
            self.layout.addWidget(self.mpl_widget.canvas)

            self.dark_button = QPushButton("切换到深色主题")
            self.dark_button.clicked.connect(lambda: self.mpl_widget.style_select("dark"))
            self.layout.addWidget(self.dark_button)

            self.light_button = QPushButton("切换到浅色主题")
            self.light_button.clicked.connect(lambda: self.mpl_widget.style_select("light"))
            self.layout.addWidget(self.light_button)

    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()