java创建一个实现 turtle 图形 API 的类。编写一个递归方法来绘制希尔伯特曲线 使用StdDraw 类来画图。代码实例

很高兴和您进行对话！关于您的问题，我会尽力给您提供答案，以下是Java实现turtle图形API的类和绘制希尔伯特曲线的代码实例：

import java.awt.Color;

public class Turtle {
    private static final double RADS = Math.PI / 180.0; // 弧度制

    private double x, y; // 初始位置为(0,0)
    private double angle; // 初始角度为0度
    private boolean penDown; // 笔是否落在画布上

    public Turtle() {
        this.x = 0;
        this.y = 0;
        this.angle = 0;
        this.penDown = true; // 初始笔落在画布上
    }

    public void move(double distance) {
        double radians = angle * RADS;
        double newX = x + distance * Math.cos(radians);
        double newY = y + distance * Math.sin(radians);
        if (penDown) { // 如果笔落在画布上则绘制图形
            drawLine(x, y, newX, newY);
        }
        x = newX;
        y = newY;
    }

    public void turn(double delta) {
        angle += delta;
    }

    public void penUp() {
        penDown = false;
    }

    public void penDown() {
        penDown = true;
    }

    private void drawLine(double x1, double y1, double x2, double y2) {
        // 使用StdDraw类画图
        StdDraw.line(x1, y1, x2, y2);
    }
}

绘制希尔伯特曲线的递归方法如下：

public class HilbertCurve {
    public static void draw(Turtle turtle, int level, double step, int sign) {
        if (level == 0) {
            return;
        }
        turtle.turn(sign * 90);
        draw(turtle, level - 1, step, -sign);
        turtle.move(step);
        turtle.turn(-sign * 90);
        draw(turtle, level - 1, step, sign);
        turtle.move(step);
        draw(turtle, level - 1, step, sign);
        turtle.turn(-sign * 90);
        turtle.move(step);
        draw(turtle, level - 1, step, -sign);
        turtle.turn(sign * 90);
    }

    public static void main(String[] args) {
        int level = 4; // 希尔伯特曲线的级别
        double step = 0.5; // 每次移动的步长
        int sign = 1; // 笔的方向

        // 设置画布属性
        StdDraw.setCanvasSize(800, 800);
        StdDraw.setXscale(0, 1);
        StdDraw.setYscale(0, 1);
        StdDraw.enableDoubleBuffering();

        Turtle turtle = new Turtle();
        turtle.penDown();
        StdDraw.setPenColor(Color.BLUE);
        draw(turtle, level, step, sign);

        StdDraw.show();
    }
}

PS：使用StdDraw类需要导入algs4.jar包。