anim3D/src/MarkerGO.i3

 Copyright (C) 1993, Digital Equipment Corporation                         
 All rights reserved.                                                      
 See the file COPYRIGHT for a full description.                            
                                                                           
 Created by Marc Najork                                                    
 Last modified on Mon Jun 13 10:38:22 PDT 1994 by najork                   




 A MarkerGO.T is a geometric object describing a marker. 


INTERFACE MarkerGO;

IMPORT Color, ColorProp, GO, MarkerTypeProp, Point3, PointProp, RealProp;

TYPE
  T <: Public;
  Public = GO.T OBJECT
  METHODS
    init () : T;
  END;

 m.init() initializes m, and returns it. The location of the marker
   is determined by the property Center. 

VAR
  Center : PointProp.Name;
  Colour : ColorProp.Name;
  Scale  : RealProp.Name;
  Type   : MarkerTypeProp.Name;

 In addition to the properties observed by all \type{GO}{T}'s, there are
   some additional properties that are observed by MarkerGO.T's:


   Center is the name of a point property that describes the point indicated
   by the marker. If no Center property is specified, the marker is drawn at
   the origin.


   Colour is the name of a color property that describes the color of the
   marker. If no Colour property is specified, the marker is drawn in white.


   Scale is the name of a real property that describes the scale of the
   marker. If no Scale property is specified, the marker is drawn with
   scale 1.


   Type is the name of a marker type property that describes the type of
   the marker (dot, cross, circle, asterisk, or X). If no Type property
   is specified, the marker is drawn as an asterisk. 


PROCEDURE New (p : Point3.T) : T;

 New(p) creates a new marker and returns it. It also attaches the
   property (Center,PointProp.NewConst(p)) to the new marker. 
 The following four procedures provide sugaring to attach the
   Center, Colour, Scale, and Type properties to geometric objects: 


PROCEDURE SetCenter (o : GO.T; v : Point3.T);

 The expression SetCenter(o,p)is equivalent to
   o.setProp(Center.bind(PointProp.NewConst(p))). 

PROCEDURE SetColour (o : GO.T; v : Color.T);

 The expression SetColour(o,c) is equivalent to
   o.setProp(Colour.bind(ColorProp.NewConst(c))). 

PROCEDURE SetScale (o : GO.T; v : REAL);

 The expression SetScale(o,r) is equivalent to
   o.setProp(Scale.bind(RealProp.NewConst(r))). 

PROCEDURE SetType (o : GO.T; v : MarkerTypeProp.Kind);

 The expression SetType(o,t) is equivalent to
   o.setProp(Type.bind(MarkerTypeProp.NewConst(t))). 

END MarkerGO.