sixxpanel.java.bak

一个画1～6次方程的JAVA源程序

import javax.swing.JPanel;
import javax.swing.JOptionPane;
import java.awt.*;
import java.util.ArrayList;
public class sixxPanel extends JPanel
{
	private int n=6;
	private final int hor=500,ver=500;
	public sliderPanel sp;
	
	public sixxPanel()
	{
		sp=new sliderPanel(this);
		setBackground(Color.white);
		setPreferredSize(new Dimension(hor,ver));
		
	}

	private double fang(double x,int i)	//求x的i次方
	{
		if(i<1)return 1.0;
		else return x*fang(x,i-1);
	}

	private double fun(double x)	//求x的函数值
	{
		double result=0;
		if(sp.L.isEmpty()!=true)
			for(int i=n;i>=0;i--)
				result+=sp.L.get(n-i)*fang(x,i);
		return result;
	}

	public void drawBase(Graphics g)
	{
		g.drawLine(0,ver/2,hor,ver/2);	//x轴
		g.drawLine(hor-4,ver/2-4,hor,ver/2);	//箭头
		g.drawLine(hor-4,ver/2+4,hor,ver/2);
		g.drawString("x",hor-10,ver/2+10);
		//刻度
		g.drawString("0",hor/2-10,ver/2+15);	//  0  刻度
		g.drawLine(hor/2-100,ver/2-4,hor/2-100,ver/2+4);	//  -1  刻度
		g.drawString("-1",hor/2-100,ver/2+15);
		g.drawLine(hor/2+100,ver/2-4,hor/2+100,ver/2+4);	//  1  刻度
		g.drawString("1",hor/2+100,ver/2+15);
		g.drawLine(hor/2-200,ver/2-4,hor/2-200,ver/2+4);	//  -2  刻度
		g.drawString("-2",hor/2-200,ver/2+15);
		g.drawLine(hor/2+200,ver/2-4,hor/2+200,ver/2+4);	//  2  刻度
		g.drawString("2",hor/2+200,ver/2+15);

/////////////********************************************************////////////////

		g.drawLine(hor/2,0,hor/2,ver);	//y轴
		g.drawLine(hor/2-4,4,hor/2,0);	//箭头
		g.drawLine(hor/2+4,4,hor/2,0);
		g.drawString("y",hor/2+4,10);
		//刻度
		g.drawLine(hor/2-4,ver/2+100,hor/2+4,ver/2+100);	//  -1  刻度
		g.drawString("-1",hor/2+4,ver/2+100);
		g.drawLine(hor/2-4,ver/2-100,hor/2+4,ver/2-100);	//  1  刻度
		g.drawString("1",hor/2+4,ver/2-100);
		g.drawLine(hor/2-4,ver/2+200,hor/2+4,ver/2+200);	//  -2  刻度
		g.drawString("-2",hor/2+4,ver/2+200);
		g.drawLine(hor/2-4,ver/2-200,hor/2+4,ver/2-200);	//  2  刻度
		g.drawString("2",hor/2+4,ver/2-200);

	}

	public void paintComponent(Graphics g)
	{
		super.paintComponent(g);
		int h,v,xl=hor/2,xr=ver/2,yl,yr;//xleft,yleft xright,yright  用于记录坐标，便于画线段
		double x,y1,y2;
		g.setColor(Color.black);

		drawBase(g);
		yl=yr=ver/2+(int)fun(0);
		for(h=1;h<=hor/2;h++)	//从y轴开始向两边扩张画500个点
		{
			x=(double)h/100;
			

			y1=fun(x);	//画x正半轴的点
			v=(int)(y1*100);
			if(v>ver/2)v=ver/2;if（v<-(ver/2))v=-(ver/2);
			g.drawLine(xr,yr,hor/2+h,ver/2-v);
			 xr=hor/2+h;yr=ver/2-v;

			y2=fun(-x);	//画x负半轴的点
			v=(int)(y2*100);
			if(v>ver/2)v=ver/2;if（v<-(ver/2))v=-(ver/2);
			g.drawLine(xl,yl,hor/2-h,ver/2-v);
			 xl=hor/2-h;yl=ver/2-v;
		}
	}
}