数学公式的可视化计算器

import sys
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.backends.backend_qtagg import FigureCanvasQTAgg as FigureCanvas
from PyQt6.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout, QHBoxLayout, QLabel, QLineEdit, QPushButton
from PyQt6.QtCore import Qt

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        # 设置窗口标题和大小
        self.setWindowTitle("Function Visualizer")
        self.setGeometry(100, 100, 800, 600)

        # 创建中心小部件和主布局
        central_widget = QWidget()
        self.setCentralWidget(central_widget)
        main_layout = QVBoxLayout(central_widget)

        # 创建顶部输入区域
        input_layout = QHBoxLayout()

        # 标签和输入框：输入函数
        self.function_label = QLabel("Enter function (e.g., 2*x + 1):")
        input_layout.addWidget(self.function_label)

        self.function_input = QLineEdit()
        self.function_input.setPlaceholderText("e.g., 2*x + 1")
        input_layout.addWidget(self.function_input)

        # 标签和输入框：输入 x 范围
        self.xrange_label = QLabel("X range (min, max):")
        input_layout.addWidget(self.xrange_label)

        self.xmin_input = QLineEdit()
        self.xmin_input.setPlaceholderText("min, e.g., -10")
        self.xmin_input.setFixedWidth(100)
        input_layout.addWidget(self.xmin_input)

        self.xmax_input = QLineEdit()
        self.xmax_input.setPlaceholderText("max, e.g., 10")
        self.xmax_input.setFixedWidth(100)
        input_layout.addWidget(self.xmax_input)

        main_layout.addLayout(input_layout)

        # 创建按钮
        self.plot_button = QPushButton("Plot Function")
        self.plot_button.setStyleSheet("background-color: #4CAF50; color: white; padding: 10px;")
        self.plot_button.clicked.connect(self.plot_function)
        main_layout.addWidget(self.plot_button)

        # 创建 Matplotlib 图表区域
        self.figure, self.ax = plt.subplots(figsize=(8, 4))
        self.canvas = FigureCanvas(self.figure)
        main_layout.addWidget(self.canvas)

        # 初始化图表
        self.ax.grid(True, linestyle='--', alpha=0.7)
        self.ax.set_xlabel("X")
        self.ax.set_ylabel("Y")
        self.ax.set_title("Function Visualization")

    def plot_function(self):
        """绘制用户输入的函数"""
        try:
            # 获取用户输入的函数和 x 范围
            function_str = self.function_input.text().strip()
            xmin = float(self.xmin_input.text() or -10)  # 默认 -10
            xmax = float(self.xmax_input.text() or 10)   # 默认 10

            if not function_str:
                self.ax.set_title("Please enter a function!")
                self.canvas.draw()
                return

            # 创建 x 数据
            x = np.linspace(xmin, xmax, 1000)  # 生成 1000 个点

            # 使用 eval 解析函数（将 x 替换为 numpy 数组）
            # 注意：为了安全性，实际生产中应使用更安全的解析方法（如 sympy）
            y = eval(function_str.replace('x', 'x'), {'x': x, 'np': np})

            # 清空当前图表并重新绘制
            self.ax.clear()
            self.ax.plot(x, y, color='blue', label=f'y = {function_str}')
            self.ax.grid(True, linestyle='--', alpha=0.7)
            self.ax.set_xlabel("X")
            self.ax.set_ylabel("Y")
            self.ax.set_title("Function Visualization")
            self.ax.legend()

            # 刷新图表
            self.canvas.draw()

        except Exception as e:
            # 显示错误信息
            self.ax.clear()
            self.ax.text(0.5, 0.5, f"Error: {str(e)}",
                        ha='center', va='center', color='red', fontsize=12)
            self.ax.set_title("Invalid Function or Range")
            self.ax.axis('off')
            self.canvas.draw()

def main():
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec())

if __name__ == "__main__":
    main()