public class Foot extends LineElement {

  PointElement C,D;	  // foot of perpendicular from point A to line CD

  Foot (PointElement Aval, LineElement CD) {
    dimension = 1;
    A = Aval;  B = new PointElement();
    C = CD.A;  D = CD.B;
  }

  Foot (PointElement Aval, PointElement Cval, PointElement Dval) {
    dimension = 1;
    A = Aval;  B = new PointElement();
    C = Cval;  D = Dval;
  }

  protected void translate (double dx, double dy) {
    B.translate(dx,dy);
  }

  protected void rotate (PointElement pivot, double ac, double as) {
    B.rotate(pivot,ac,as);
  }

  protected void update() {B.toFoot(A,C,D);}

}