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java如何画抛物线

2026-03-19 02:41:16Java

使用 Java 绘制抛物线的方法

使用 Java Swing 绘制抛物线

Java Swing 提供了 JPanel 和 Graphics 类，可用于绘制抛物线。以下是一个示例代码：

import javax.swing.*;
import java.awt.*;

public class ParabolaDrawing extends JPanel {
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g;
        g2d.setColor(Color.BLUE);
        g2d.setStroke(new BasicStroke(2));

        int width = getWidth();
        int height = getHeight();
        int centerX = width / 2;
        int centerY = height / 2;

        // 绘制坐标系
        g2d.drawLine(0, centerY, width, centerY); // X轴
        g2d.drawLine(centerX, 0, centerX, height); // Y轴

        // 绘制抛物线 y = a*x^2 + b*x + c
        double a = 0.01;
        double b = 0;
        double c = 0;
        g2d.setColor(Color.RED);

        for (int x = -centerX; x < centerX; x++) {
            int y = (int) (a * x * x + b * x + c);
            int drawX = centerX + x;
            int drawY = centerY - y;
            g2d.drawLine(drawX, drawY, drawX, drawY);
        }
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("抛物线绘制");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(800, 600);
        frame.add(new ParabolaDrawing());
        frame.setVisible(true);
    }
}

使用 JavaFX 绘制抛物线

JavaFX 提供了更现代的图形绘制功能。以下是使用 JavaFX 绘制抛物线的示例：

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Line;
import javafx.scene.shape.Polyline;
import javafx.stage.Stage;

public class ParabolaFX extends Application {
    @Override
    public void start(Stage primaryStage) {
        Pane pane = new Pane();
        int width = 800;
        int height = 600;
        int centerX = width / 2;
        int centerY = height / 2;

        // 绘制坐标系
        Line xAxis = new Line(0, centerY, width, centerY);
        Line yAxis = new Line(centerX, 0, centerX, height);
        pane.getChildren().addAll(xAxis, yAxis);

        // 绘制抛物线
        Polyline parabola = new Polyline();
        double a = 0.01;
        double b = 0;
        double c = 0;

        for (int x = -centerX; x < centerX; x++) {
            double y = a * x * x + b * x + c;
            parabola.getPoints().addAll((double) (centerX + x), (double) (centerY - y));
        }
        parabola.setStroke(javafx.scene.paint.Color.RED);
        pane.getChildren().add(parabola);

        Scene scene = new Scene(pane, width, height);
        primaryStage.setTitle("JavaFX 抛物线");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}