/* Auteur: Nicolas JANEY                                */
/* nicolas.janey@univ-fcomte.fr                         */
/* Novembre 2006                                        */

public class Rectangle {
  public Position ig;
  public Position sd;

  public Rectangle() {
    ig = new Position();
    sd = new Position();
  }

  public Rectangle(float xmin,float ymin,float xmax,float ymax) {
    ig = new Position(xmin,ymin);
    sd = new Position(xmax,ymax);
  }

  public Rectangle(Position ig,Position sd) {
    this.ig = new Position(ig);
    this.sd = new Position(sd);
  }

  public Rectangle(Rectangle r) {
    ig = new Position(r.ig);
    sd = new Position(r.sd);
  }
  
  private int codeZone(Position p) {
    int cz = ( p.x < ig.x ) ? 0x01 : 0x00;
    if ( p.x > sd.x ) 
      cz += 0x02;
    if ( p.y < ig.y ) 
      cz += 0x04;
    if ( p.y > sd.y ) 
      cz += 0x08;
    return(cz);
  }
  
  public Segment clip(Segment s) {
    s = new Segment(s);
    int ci = codeZone(s.pi);
    int cf = codeZone(s.pf);
    while ( ( ( ci != 0 ) || ( cf !=0 ) ) && ( (ci&cf) == 0 ) ) {
      if ( ci == 0 ) {
        ci = cf;
        cf = 0;
        Position p = s.pi;
        s.pi = s.pf;
        s.pf = p; }
      if ( (ci & 0x0001) != 0 ) {
        s.pi.y = s.ordonnee(ig.x);
        s.pi.x = ig.x; }
        else
        if ( (ci & 0x0002) != 0 ) {
          s.pi.y = s.ordonnee(sd.x);
          s.pi.x = sd.x; }
          else
          if ( (ci & 0x0004) != 0 ) {
            s.pi.x = s.abscisse(ig.y);
            s.pi.y = ig.y; }
            else {
            s.pi.x = s.abscisse(sd.y);
            s.pi.y = sd.y; }
      ci = codeZone(s.pi); }
    return((ci == 0 ) ? s : null);
  }
  
  public String toString() {
    return("["+ig+","+sd+"]");
  }
}