java - 绘制递归雪花

Question

我遇到这个问题，我必须绘制一个递归雪花，使得雪花有 6 条来自中心点的线，每条线彼此相距 60 度，然后每条线的端点就是中心点另一片。每次它 fork 成另一片时，长度就会减半。长度定义为薄片的一侧。这种递归不断发生，直到长度减小到 20 像素之类的距离，此时您将无法再区分不同的薄片。

我知道递归只是一种调用自身的方法，但我只是很难设置这个问题。到目前为止，我所掌握的是绘制初始薄片的数学知识，但我只是不知道如何设置递归来绘制薄片。

这是我到目前为止所拥有的。

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

public class SnowFlake extends JPanel {

    private MainWindow panel;
    private int x1OfFlake = 400;
    private int y1OfFlake = 400;
    private int maxLength = 200;  // this is length of, 1 0f 6 branches for each individual flake

    public SnowFlake() {
        // generateRandCoodinatesLength();
    }

    public void generateRandCoodinatesLength() {
        Random rn = new Random();
        maxLength = rn.nextInt(200) + 100;
        x1OfFlake = rn.nextInt(700) + 100;
        y1OfFlake = rn.nextInt(700) + 100;
    }


    public void paint(Graphics g) {
        drawFlake(levels, x1OfFlake, y1OfFlake, g);  // x1, y1, x2, y2
    }

    public void drawFlake(int level, int x1, int y1, Graphics g){
        //below was just how I made sure my picture was correct
        /*
          g.drawLine(x1, y1, 600, 400); //1
          g.drawLine(x1, y1, 500, 227); //2
          g.drawLine(x1, y1, 300, 227); //3
          g.drawLine(x1, y1, 200, 400); //4
          g.drawLine(x1, y1, 300, 573); //5
          g.drawLine(x1, y1, 500, 573); //6
        */
        g.drawLine(x1, y1, x1 + maxLength, y1);  // 1
        g.drawLine(x1, y1, x1 + (maxLength / 2), y1 - ((int) ((maxLength / 2) * Math.sqrt(3))));  // 2
        g.drawLine(x1, y1, x1 - (maxLength / 2), y1 - ((int) ((maxLength / 2) * Math.sqrt(3))));  // 3
        g.drawLine(x1, y1, x1 - maxLength, y1); // 4
        g.drawLine(x1, y1, x1 - (maxLength / 2), y1 + ((int) ((maxLength / 2) * Math.sqrt(3))));  // 5
        g.drawLine(x1, y1, x1 + (maxLength / 2), y1 + ((int) ((maxLength / 2) * Math.sqrt(3))));  // 6
    }
}

这就是最终结果应该是什么样的，除了绘制了更多分支。

picture

Answer 1

这可以让你更接近你想要的

public void drawFlake(int level, float angleDegrees, Graphics g) {
    /* 
     * Exit condition
     * If the max number of levels has been reached, 
     * or the maxLength is no longer visible when drawn
     */
    if (level >= MAX_LEVEL || maxLength == 0) {
        return;
    }

    /*
     * Secondary condition, increment the level if we've gone around the 
     * circle once
     */
    if (angleDegrees >= 360) {
        maxLength *= .9;
        drawFlake(level + 1, 0, g);
        return;
    }

    g.drawLine(
        centerX,
        centerY,
        centerX + (int) (maxLength * Math.sin(Math.toRadians(angleDegrees))),
        centerY + (int) (maxLength * Math.cos(Math.toRadians(angleDegrees))));

    int currentLevelAngleIncrement = 60 / (level + 1);
    drawFlake(level, angleDegrees + currentLevelAngleIncrement, g);
}

结果是这样的..