import java.awt.*;

public class segment extends line
{
     public segment(point P, point Q)
     {
	  super(P, Q);
     }

     public segment(double x1, double y1, double x2, double y2)
     {
	  super(x1, y1, x2, y2);
     }

     public segment(point P, double m)
     {
	  super(P, m);
     }

     public double length()
     {
	  return(Math.sqrt((p.x - q.x)*(p.x - q.x) + (p.y - q.y)*(p.y - q.y)));
     }

     public void draw(GeometryWindow G)
     {
	  if (!exists() || hidden)
	       return;

	  G.setColor(color);
	  G.drawSegment(p.x, p.y, q.x, q.y);
     }

     public point coordOnShape(double X, double Y)
     {
	  point P = super.coordOnShape(X, Y);
	  double tx = q.x - p.x;
	  double ty = q.y - p.y;

	  double pTanDist = p.x * tx + p.y * ty;
	  double qTanDist = q.x * tx + q.y * ty;

	  double tanDist = P.x*tx + P.y*ty;
	  if (tanDist < pTanDist)
	       return(new point(p.x, p.y));
	  else if (tanDist > qTanDist)
	       return(new point(q.x, q.y));
	  else
	       return(P);
     }

     public boolean mouseDown(double X, double Y)
     {
	  if (hidden)
	       return(false);

	  double m = slope();
	  double tx = q.x - p.x;
	  double ty = q.y - p.y;
	  double nx = -(q.y - p.y);
	  double ny = q.x - p.x;
	  double length = Math.sqrt(tx*tx + ty*ty);
	  tx /= length;
	  ty /= length;

	  length = Math.sqrt(nx*nx + ny*ny);
	  nx /= length;
	  ny /= length;

	  double baseDist = p.x * nx + p.y * ny;
	  double pointDist = X * nx + Y * ny;

	  double pTanDist = p.x * tx + p.y * ty;
	  double qTanDist = q.x * tx + q.y * ty;
	  double tanDist = X * tx + Y * ty;

	  if ( (Math.abs(pointDist - baseDist) < clickRange) &&
	       (tanDist < qTanDist) && (tanDist > pTanDist) )
	  {
	       dragging = true;
	       
	       double dx = (pointDist - baseDist) * nx;
	       double dy = (pointDist - baseDist) * ny;

	       p.translate(dx, dy);
	       q.translate(dx, dy);
	       
	       dragX = X;
	       dragY = Y;
	       return(true);
	  }
	  return(false);	  
     }
};