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 GraphicViews operations.

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

SEE ALSO

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