import java.applet.Applet;
import java.awt.event.*;
import java.awt.*;

import java.awt.geom.*;


public class Segment {
    Complex[] z=new Complex[2];
    int[] INDEX=new int[3];
    Color COLOR;

    public Segment() {}

    public Segment(Complex z1,Complex z2) {
	this.z[0]=z1;
	this.z[1]=z2;
	INDEX[0]=0;
	INDEX[1]=0;
	INDEX[2]=0;
	COLOR=Color.white;
    }

    public GeneralPath toGeneralPath() {
	GeneralPath gp=new GeneralPath();
	gp.moveTo((float)(z[0].x),(float)(z[0].y));
	gp.lineTo((float)(z[1].x),(float)(z[1].y));
	return(gp);
    }

    public double length() {
	return(Complex.dist(z[0],z[1]));
    }

    public void print() {
	z[0].print();
	z[1].print();
    }

    public static Segment segMerge(Segment S1,Segment S2) {

	int k=Complex.zeroOriented(S1.z[0],S1.z[1],S2.z[0]);
	if(k==0) return(null);
	k=Complex.zeroOriented(S1.z[0],S1.z[1],S2.z[1]);
	if(k==0) return(null);

	Complex z2=Complex.minus(S1.z[1],S1.z[0]);
	Complex z3=Complex.minus(S2.z[0],S1.z[0]);
	Complex z4=Complex.minus(S2.z[1],S1.z[0]);
	Complex z1=new Complex(0,0);
	if(z2.norm()<.000001) return(null);
	z3=Complex.divide(z3,z2);
	z4=Complex.divide(z4,z2);
	z2=new Complex(1,0);
	double r1=z1.x;
	double r2=z2.x;
	double r3=z3.x;
	double r4=z4.x;
	if(Math.max(r1,r2)<Math.min(r3,r4)) return(null);   //segments disjoint
	if(Math.min(r1,r2)>Math.max(r3,r4)) return(null);   //segments disjoint
	double s1=Math.min(Math.min(Math.min(r1,r2),r3),r4);
	double s2=Math.max(Math.max(Math.max(r1,r2),r3),r4);
	Segment T=new Segment();

	if(r1<s1+.00000001) T.z[0]=S1.z[0];
	if(r2<s1+.00000001) T.z[0]=S1.z[1];
	if(r3<s1+.00000001) T.z[0]=S2.z[0];
	if(r4<s1+.00000001) T.z[0]=S2.z[1];
	if(r1>s2-.00000001) T.z[1]=S1.z[0];
	if(r2>s2-.00000001) T.z[1]=S1.z[1];
	if(r3>s2-.00000001) T.z[1]=S2.z[0];
	if(r4>s2-.00000001) T.z[1]=S2.z[1];
	return(T);
    }




    public Segment chopX(double X) {

	//both points to the left
	if((z[0].x>=X)&&(z[1].x>=X)) return(null);

	//both points to the right
	if((z[0].x<=-X)&&(z[1].x<=-X)) return(null);

	//both points inside
	if((Math.abs(z[0].x)<X)&&(Math.abs(z[1].x))<X) return(new Segment(z[0],z[1]));

	   Complex[] w=new Complex[10];
	   Vector V=new Vector();

	   if((Math.abs(z[0].x)<X)&&(z[1].x>=X)) {
	       w[1]=new Complex(X,0);
	       w[2]=new Complex(X,1);
	       w[3]=V.findCross2(z[0],z[1],w[1],w[2]);
	       return(new Segment(z[0],w[3]));
	   }

	   if((Math.abs(z[1].x)<X)&&(z[0].x>=X)) {
	       w[1]=new Complex(X,0);
	       w[2]=new Complex(X,1);
	       w[3]=V.findCross2(z[0],z[1],w[1],w[2]);
	       return(new Segment(z[1],w[3]));
	   }


	   if((Math.abs(z[0].x)<X)&&(z[1].x<=-X)) {
	       w[1]=new Complex(-X,0);
	       w[2]=new Complex(-X,1);
	       w[3]=V.findCross2(z[0],z[1],w[1],w[2]);
	       return(new Segment(z[0],w[3]));
	   }

	   if((Math.abs(z[1].x)<X)&&(z[0].x<=-X)) {
	       w[1]=new Complex(-X,0);
	       w[2]=new Complex(-X,1);
	       w[3]=V.findCross2(z[0],z[1],w[1],w[2]);
	       return(new Segment(z[1],w[3]));
	   }

	   if((z[0].x>=X)&&(z[1].x<=-X)) {
               w[1]=new Complex(X,0);
	       w[2]=new Complex(X,1);
	       w[3]=V.findCross2(z[0],z[1],w[1],w[2]);
               w[1]=new Complex(-X,0);
	       w[2]=new Complex(-X,1);
	       w[4]=V.findCross2(z[0],z[1],w[1],w[2]);
	       return(new Segment(w[3],w[4]));
	   }

	   if((z[1].x>=X)&&(z[0].x<=-X)) {
               w[1]=new Complex(X,0);
	       w[2]=new Complex(X,1);
	       w[3]=V.findCross2(z[0],z[1],w[1],w[2]);
               w[1]=new Complex(-X,0);
	       w[2]=new Complex(-X,1);
	       w[4]=V.findCross2(z[0],z[1],w[1],w[2]);
	       return(new Segment(w[3],w[4]));
	   }
	   return(null);
    }


    public Segment chopY(double Y) {
	if(this==null) return(null);
	Segment S=new Segment(new Complex(z[0].y,z[0].x),new Complex(z[1].y,z[1].x));
	Segment T=S.chopX(Y);
	if(T==null) return(null);
	T=new Segment(new Complex(T.z[0].y,T.z[0].x),new Complex(T.z[1].y,T.z[1].x));
	return(T);
    }

    public Segment chop(double X,double Y) {
	if(this==null) return(null);
	Segment S1=chopX(X);
	if(S1==null) return(null);
	Segment S2=S1.chopY(Y);
	return(S2);
    }


}