Matplotlib 运行时动态切换图表主题：深入理解与实现

import matplotlib.pyplot as plt
import numpy as np
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QPushButton
from PyQt5.QtCore import Qt

class MatplotlibDynamicThemeWidget(QWidget):
    """
    一个包含 Matplotlib 图表并支持动态主题切换的 PyQt 控件。
    """
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setWindowTitle("Matplotlib 动态主题切换示例")

        # 初始化 Matplotlib 图表
        self.figure, self.ax = plt.subplots(figsize=(6, 4))
        self.canvas = FigureCanvas(self.figure)

        # 布局
        self.layout = QVBoxLayout(self)
        self.layout.addWidget(self.canvas)

        # 主题切换按钮
        self.theme_button = QPushButton("切换主题 (当前: 默认)")
        self.theme_button.clicked.connect(self._toggle_theme)
        self.layout.addWidget(self.theme_button)

        self.current_theme = "default"
        self._plot_initial_data()
        self._apply_theme("default") # 初始应用默认主题

    def _plot_initial_data(self):
        """绘制初始数据"""
        self.ax.clear() # 清除旧数据，保留轴属性
        x = np.linspace(0, 10, 100)
        y = np.sin(x)
        self.ax.plot(x, y, label="Sin曲线", color='tab:blue') # 设置一个明确的线条颜色
        self.ax.legend()
        self.ax.set_title("动态主题示例图")
        self.ax.set_xlabel("X轴")
        self.ax.set_ylabel("Y轴")
        self.canvas.draw()

    def _apply_theme(self, theme_name):
        """
        根据主题名称应用不同的视觉属性。
        :param theme_name: 要应用的主题名称 ("default" 或 "dark")。
        """
        # 定义主题属性
        if theme_name == "dark":
            # 暗色主题属性
            fig_bg = "black"
            ax_bg = "#2b2b2b" # 绘图区域的深灰色
            text_color = "white"
            grid_color = "#444444"
            spine_color = "white"
        else: # "default" (亮色主题)
            # 默认主题属性
            fig_bg = "white"
            ax_bg = "white"
            text_color = "black"
            grid_color = "#cccccc"
            spine_color = "black"

        # 应用到 Figure 对象
        self.figure.set_facecolor(fig_bg)
        self.figure.set_edgecolor(fig_bg) # 通常与背景色一致

        # 应用到 Axes 对象
        self.ax.set_facecolor(ax_bg)

        # 更新标题、轴标签颜色
        self.ax.set_title(self.ax.get_title(), color=text_color)
        self.ax.set_xlabel(self.ax.get_xlabel(), color=text_color)
        self.ax.set_ylabel(self.ax.get_ylabel(), color=text_color)

        # 更新刻度、刻度标签颜色
        self.ax.tick_params(axis='x', colors=text_color)
        self.ax.tick_params(axis='y', colors=text_color)

        # 更新轴边框颜色
        self.ax.spines['bottom'].set_color(spine_color)
        self.ax.spines['top'].set_color(spine_color)
        self.ax.spines['right'].set_color(spine_color)
        self.ax.spines['left'].set_color(spine_color)

        # 更新网格线颜色
        self.ax.grid(True, color=grid_color)

        # 更新图例文本颜色
        legend = self.ax.get_legend()
        if legend:
            legend.set_facecolor(ax_bg) # 图例背景色与绘图区域一致
            legend.set_edgecolor(spine_color) # 图例边框色与轴边框一致
            for text in legend.get_texts():
                text.set_color(text_color)

        # 刷新画布以显示更改
        self.canvas.draw()
        self.current_theme = theme_name
        self.theme_button.setText(f"切换主题 (当前: {theme_name})")

    def _toggle_theme(self):
        """切换当前主题"""
        if self.current_theme == "dark":
            self._apply_theme("default")
        else:
            self._apply_theme("dark")

if __name__ == '__main__':
    app = QApplication([])
    widget = MatplotlibDynamicThemeWidget()
    widget.show()
    app.exec_()