JAVA总结——静态科赫曲线和科赫雪花

经过几天的分析和计算，终于画出了传说中的科赫曲线（当然只是最初步的静态的曲线）。在这个过程中学到了一些新的东西，总体来说还是挺好玩的。

depth=1


depth=3


depth=7


代码如下：创建了2个类
第一个类：DrawBoard

package source;

import java.awt.Graphics;
import javax.swing.JFrame;

public class DrawBoard extends JFrame{
	Graphics g;
	
	//主函数
	public static void main(String [] args){
		DrawBoard db = new DrawBoard();
		db.createboard();
	}
	//创建窗体
	public void createboard(){
		
		this.setTitle("科赫曲线");
		this.setSize(800, 800);
		this.setDefaultCloseOperation(3);
		this.setResizable(false);
		this.setVisible(true);
		
		//创建一个画布对象
		Graphics g =this.getGraphics();
		BoardListener lis = new BoardListener(g);
		this.addMouseListener(lis);	
	}
}

第二个类：BoardListener

package source;

import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

public class BoardListener implements MouseListener{
	Graphics g;
//	double x1,x2,x3,x4,x5,y1,y2,y3,y4,y5,k;
	int depth = 7;
	public BoardListener(Graphics g1){
		g=g1;
	}
	
	public void mouseClicked(MouseEvent e) {
		digui(100,400,600,400,this.depth);
	}

	
	public void mouseEntered(MouseEvent arg0) {
	
	}

	
	public void mouseExited(MouseEvent arg0) {
		
	}

	
	public void mousePressed(MouseEvent arg0) {
		
	}

	
	public void mouseReleased(MouseEvent arg0) {
		
	}
	public void digui(double x1,double y1,double x2,double y2,int depth){
		if(depth<=1){
			g.drawLine((int)x1,(int)y1,(int)x2,(int)y2);
		}
		else {
		double x3=(2*x1+x2)/3;double y3=(2*y1+y2)/3;
		double x4=(x1+2*x2)/3;double y4=(y1+2*y2)/3;
		double x5=0,y5=0;
		double k=(y4-y3)/(x4-x3);
		if(y3==y4){
			x5=(x3+x4)/2;y5=y3-(x4-x3)*Math.sqrt(3)/2;
		}
		else{ 
			if(k<0){
				x5=x1;y5=y4;
			}
			if(k>0){
				x5=x2;y5=y3;
			}
		}
		digui(x1,y1,x3,y3,depth-1);
		digui(x3,y3,x5,y5,depth-1);
		digui(x5,y5,x4,y4,depth-1);
		digui(x4,y4,x2,y2,depth-1);
		}
	}
}

总体来说，遇到的困难有以下几个：
1.存点问题：
  (x5,y5)的情况要计算3种，每种的（x3,y3）（x4,y4）算法相同，只有（x5,y5）算法
  不同，要用选择来讨论情况。
2.x3,y3,x4,y4一定要定义成局部变量，即double x3=(2*x1+x2)/3;而不能在开头定义double x3, x3=(2*x1+x2)/3！！！！！！
3.递归函数中应该写成depth-1,而不能是depth--！


将一个正三角形的每条边都做如上变换，即可得到科赫雪花
[img]

[/img]


代码如下

package source;

import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

public class BoardListener implements MouseListener{
	Graphics g;
	int depth = 10;
	public BoardListener(Graphics g1){
		g=g1;
	}
	
	public void mouseClicked(MouseEvent e) {
		digui1(100,200,600,200,this.depth);
		digui2(100,200,350,633,this.depth);
		digui3(600,200,350,633,this.depth);
	}

	public void mouseEntered(MouseEvent arg0) {
	
	}

	public void mouseExited(MouseEvent arg0) {
		
	}

	public void mousePressed(MouseEvent arg0) {
		
	}

	public void mouseReleased(MouseEvent arg0) {
		
	}
	
	//第一个递归函数
	public void digui1(double x1,double y1,double x2,double y2,int depth){
		if(depth<=1){
			g.drawLine((int)x1,(int)y1,(int)x2,(int)y2);
		}
		else {
		//一定要把x1...x5定义成局部变量！！！
		double x3=(2*x1+x2)/3;double y3=(2*y1+y2)/3;
		double x4=(x1+2*x2)/3;double y4=(y1+2*y2)/3;
		double x5=0,y5=0;
		double k=(y4-y3)/(x4-x3);
		if(y3==y4){
			x5=(x3+x4)/2;y5=y3-(x4-x3)*Math.sqrt(3)/2;
		}
		else{ 
			if(k<0){
				x5=x1;y5=y4;
			}
			if(k>0){
				x5=x2;y5=y3;
			}
		}
		digui1(x1,y1,x3,y3,depth-1);
		digui1(x3,y3,x5,y5,depth-1);
		digui1(x5,y5,x4,y4,depth-1);
		digui1(x4,y4,x2,y2,depth-1);
		}
	}
	
	
	//第二个递归函数
	public void digui2(double x1,double y1,double x2,double y2,int depth){
		if(depth<=1){
			g.drawLine((int)x1,(int)y1,(int)x2,(int)y2);
		}
		else {
		//一定要把x1...x5定义成局部变量！！！
		double x3=(2*x1+x2)/3;double y3=(2*y1+y2)/3;
		double x4=(x1+2*x2)/3;double y4=(y1+2*y2)/3;
		double x5=0,y5=0;
		double k=(y4-y3)/(x4-x3);
		if(y3==y4){
			x5=(x3+x4)/2;y5=y3+(x4-x3)*Math.sqrt(3)/2;
		}
		else{ 
			if(k<0){
				x5=x2;y5=y3;
			}
			if(k>0){
				x5=x1;y5=y4;
			}
		}
		digui2(x1,y1,x3,y3,depth-1);
		digui2(x3,y3,x5,y5,depth-1);
		digui2(x5,y5,x4,y4,depth-1);
		digui2(x4,y4,x2,y2,depth-1);
		}
	}
	public void digui3(double x1,double y1,double x2,double y2,int depth){
		if(depth<=1){
			g.drawLine((int)x1,(int)y1,(int)x2,(int)y2);
		}
		else {
		//一定要把x1...x5定义成局部变量！！！
		double x3=(2*x1+x2)/3;double y3=(2*y1+y2)/3;
		double x4=(x1+2*x2)/3;double y4=(y1+2*y2)/3;
		double x5=0,y5=0;
		double k=(y4-y3)/(x4-x3);
		if(y3==y4){
			x5=(x3+x4)/2;y5=y3+(x3-x4)*Math.sqrt(3)/2;
		}
		else{ 
			if(k<0){
				x5=x1;y5=y4;
			}
			if(k>0){
				x5=x2;y5=y3;
			}
		}
		digui3(x1,y1,x3,y3,depth-1);
		digui3(x3,y3,x5,y5,depth-1);
		digui3(x5,y5,x4,y4,depth-1);
		digui3(x4,y4,x2,y2,depth-1);
		}
	}
}