科赫雪花的Java递归实现

今天要编写k阶Koch雪花的递归实现（K值需要您手动输入）至于什么是Koch雪花，请自己百度.

首先，考虑如何编写此程序. 当count = 0时java制作雪花，它应该是一个三角形. 这三点由您在开始时确定，以后的更改将基于这三点. 如果不为0，则需要计算相对于三角形的9个点，每边两个点，并计算与该三角形相对应的三角形的第三个顶点.

首先在JFrame中添加一个面板，我们需要在该面板上绘制.

让我们再次看这张照片. 这张图片描述了从两个点计算另外三个点的过程.

立即开始在面板中绘图:

static class showpanel extends JPanel{ 
    int number = 0; 
    public void setNumber(int number) { 
      this.number = number; 
      repaint(); 
    } 
    public void paintComponent(Graphics g) { 
      super.paintComponent(g);//画一个简单的panel 
       
      int side =(int)(Math.min((int)getWidth(),(int)getHeight())*0.8); 
      int high =(int)(side*Math.cos(Math.toRadians(30))); 
       
       Point p1 = new Point(getWidth() / 2, 10); 
       Point p2 = new Point(getWidth() / 2 - side / 2, 10 + high); 
       Point p3 = new Point(getWidth() / 2 + side / 2, 10 + high); 
        
       playKochSnowFlake(g, number, p1, p2); 
       playKochSnowFlake(g, number, p2, p3); 
       playKochSnowFlake(g, number, p3, p1); 
       
    } 

现在开始编写递归函数.

public static void playKochSnowFlake(Graphics g,int number,Point p1,Point p2) { 
      if(number == 0){ 
        g.drawLine(p1.x, p1.y,p2.x, p2.y); 
      } 
      else{ 
         int deltaX = p2.x - p1.x; 
          int deltaY = p2.y - p1.y; 
 
          Point x = new Point(p1.x + deltaX / 3, p1.y + deltaY / 3); 
          Point y = new Point(p1.x + deltaX * 2 / 3, p1.y + deltaY * 2 / 3); 
          Point z = new Point( 
           (int)((p1.x + p2.x) / 2 + Math.sin(Math.toRadians(60)) * (p1.y - p2.y) / 3), 
           (int)((p1.y + p2.y) / 2 + Math.sin(Math.toRadians(60)) * (p2.x - p1.x) / 3)); 
          playKochSnowFlake(g, number - 1, p1, x); 
          playKochSnowFlake(g, number - 1, x, z); 
          playKochSnowFlake(g, number - 1, z, y); 
          playKochSnowFlake(g, number - 1, y, p2); 
      } 
    } 

然后将JTextField jta添加到主面板，它输入的数据将传递给number. 因此java制作雪花，为其添加一个侦听器. 如果已经有数据输入，则调用setNumber（）函数来设置数字变量.

jta.addActionListener(new ActionListener() { 
       
      public void actionPerformed(ActionEvent arg0) { 
        spl.setNumber(Integer.parseInt(jta.getText()));        
      } 
    }); 

整个过程就完成了，剩下的就是简短格式设置.

下面是完整的Java代码:

import java.awt.BorderLayout; 
import java.awt.FlowLayout; 
import java.awt.Graphics; 
import java.awt.Point; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import javax.swing.JFrame; 
import javax.swing.JLabel; 
import javax.swing.JPanel; 
import javax.swing.JTextField; 
 
public class SnowFlake extends JFrame { 
   
  private JTextField jta = new JTextField(5); 
  private showpanel spl = new showpanel(); 
   
  static class showpanel extends JPanel{ 
    int number = 0; 
    public void setNumber(int number) { 
      this.number = number; 
      repaint(); 
    } 
    public void paintComponent(Graphics g) { 
      super.paintComponent(g);//画一个简单的panel 
       
      int side =(int)(Math.min((int)getWidth(),(int)getHeight())*0.8); 
      int high =(int)(side*Math.cos(Math.toRadians(30))); 
       
       Point p1 = new Point(getWidth() / 2, 10); 
       Point p2 = new Point(getWidth() / 2 - side / 2, 10 + high); 
       Point p3 = new Point(getWidth() / 2 + side / 2, 10 + high); 
        
       playKochSnowFlake(g, number, p1, p2); 
       playKochSnowFlake(g, number, p2, p3); 
       playKochSnowFlake(g, number, p3, p1); 
       
    } 
    public static void playKochSnowFlake(Graphics g,int number,Point p1,Point p2) { 
      if(number == 0){ 
        g.drawLine(p1.x, p1.y,p2.x, p2.y); 
      } 
      else{ 
         int deltaX = p2.x - p1.x; 
          int deltaY = p2.y - p1.y; 
 
          Point x = new Point(p1.x + deltaX / 3, p1.y + deltaY / 3); 
          Point y = new Point(p1.x + deltaX * 2 / 3, p1.y + deltaY * 2 / 3); 
          Point z = new Point( 
           (int)((p1.x + p2.x) / 2 + Math.sin(Math.toRadians(60)) * (p1.y - p2.y) / 3), 
           (int)((p1.y + p2.y) / 2 + Math.sin(Math.toRadians(60)) * (p2.x - p1.x) / 3)); 
          playKochSnowFlake(g, number - 1, p1, x); 
          playKochSnowFlake(g, number - 1, x, z); 
          playKochSnowFlake(g, number - 1, z, y); 
          playKochSnowFlake(g, number - 1, y, p2); 
      } 
    } 
  } 
   
  public SnowFlake() { 
    JPanel panel = new JPanel(); 
    panel.setLayout(new FlowLayout()); 
    panel.add(new JLabel("Please input the number")); 
    panel.add(jta); 
    add(spl,BorderLayout.CENTER); 
    add(panel,BorderLayout.SOUTH); 
    jta.addActionListener(new ActionListener() { 
       
      public void actionPerformed(ActionEvent arg0) { 
        spl.setNumber(Integer.parseInt(jta.getText()));        
      } 
    }); 
  } 
  public static void main(String args[]) { 
    SnowFlake snowFlake = new SnowFlake(); 
    snowFlake.setSize(300, 300); 
    snowFlake.setTitle("SnowFlake"); 
    snowFlake.setLocationRelativeTo(null); 
    snowFlake.setVisible(true); 
  } 
} 

效果图:

以上是本文的全部内容. 希望对大家的学习有所帮助. 我也希望每个人都支持该脚本主页.

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