GVUpdater(3U)						    InterViews Reference Manual 					     GVUpdater(3U)

NAME

       GVUpdater - updates GraphicViews structure to match its subject

SYNOPSIS

       #include <Unidraw/Components/gvupdater.h>

DESCRIPTION

       GVUpdater  is  an  implementation  class  that  GraphicViews uses to keep its state and structure consistent with its GraphicComps subject.
       GVUpdater ensures that subject's immediate children are identical to the view's in number and graphics state attributes.  It  also  ensures
       that  the  root	GraphicViews  and GraphicComps themselves have the same graphics state.  GVUpdater does not ensure that it will detect and
       update changes made to deeper child nodes.

PUBLIC OPERATIONS

       GVUpdater(GraphicView*)
	      The constructor takes the GraphicView that it will be updating as a parameter and stores it in the protected member  _gv.  Normally,
	      GraphicViews are the only objects that will instantiate GVUpdater.

       virtual void Update()
	      Update the GraphicView to make it consistent with its subject.

PROTECTED OPERATIONS

       void UpdateStructure()
       void UpdateState()
	      The  Update  procedure  takes place in two stages.  The subject's and view's structures are reconciled first by UpdateStructure, and
	      then the view's graphic state is changed to match the subjects with UpdateState.

       void AddDamage(Graphic*)
       void IncurDamage(Graphic*)
       void Unselect(GraphicView*)
       virtual void Add(GraphicView*)
       virtual void Append(GraphicView*)
       virtual void InsertBefore(Iterator, GraphicView*)
	virtual void Remove(Iterator&)
       virtual void DeleteView(Iterator&)
	      GVUpdater is a friend of GraphicViews.  These convenience operations provide an interface  to  the  corresponding  protected  Graph-
	      icViews operations.

       virtual ClassId ViewCategory()
	      Returns  the  view  category  (see  classes(3U))	GVUpdater  will use to instantiate views of subjects.  ViewCategory returns COMPO-
	      NENT_VIEW by default.

SEE ALSO

       GraphicComp(3U), GraphicView(3U), classes(3U)

Unidraw 							  19 January 1991						     GVUpdater(3U)