java递归实现科赫雪花

  • Z时代
  • 2024-01-10
  • 分类：综合

今天来写k阶科赫雪花的递归实现，(K值需要你手动输入)至于科赫雪花是什么请大家自行百度。

首先来思考这个程序怎么写，当 count = 0 时就应该是一个三角形，这三个点是你一开始就确定的，以后的改变都依据这三个点发展的。当不是0的时候就需要计算相对于这个三角形的9个点，分别是每条边上的两个点，和它对应的三角形第三个顶点。

首先在JFrame中添加一个panel，我们需要在这个panel上画图。

大家再来看这个图片，这张图介绍了通过两个点来计算其他三个点的过程。

现在开始在panel中画图：

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); 
      } 
    }

然后在主面板中加入一个JTextField   jta 它输入的数据要传入到number中。所以为其添加一个监听器。 已有数据输入就调用其中的setNumber()函数设置number变量。 

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

 所以总体已经完成了，剩下的就是简答的窗体设置。

下面贴一个完整的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：

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