Box, HBox, VBox - tile interactors in a box

SYNOPSIS

       #include <InterViews/box.h>

DESCRIPTION

       A  box  is  a scene of interactors that are tiled side-by-
       side in the available space.  Interactors are placed left-
       to-right  in a horizontal box, and top-to-bottom in a ver-
       tical box.

       A box will try to stretch or shrink the interactors inside
       it  to fit the available space.  The natural size of a box
       is the sum of its elements along the major axis,  and  the
       maximum  along  its  minor  axis.   A box's stretchability
       (shrinkability) is the sum of its elements along its major
       axis and the minimum of its elements along its minor axis.

PUBLIC OPERATIONS

       HBox(...)
       VBox(...)
              Create a new box.  Zero to seven interactors may be
              passed  as  arguments; the interactors are inserted
              into the box.

       void Align(Alignment)
              Set the alignment mode that the box uses  to  place
              elements  along the minor axis.  The default align-
              ment for an hbox is Bottom; other choices  are  Top
              and  Center.   The  default alignment for a vbox is
              Left; other choices are Right and Center.

       void Insert(Interactor*)
              Append an interactor to the box.  Components of  an
              hbox  (vbox) will appear left-to-right (top-to-bot-
              tom) in the order in which they are inserted.

       void Change(Interactor*)
              Notify the box that the  given  interactor's  shape
              has  changed.   If  change propagation is true, the
              box will modify its own shape to reflect the change
              and  notify its parent.  Regardless of propagation,
              the box will recompute the positions of the  compo-
              nent  interactors and update any that have changed.

       void Remove(Interactor*)
              Take an element of out  a  box.   Remove  does  not
              cause  any immediate change to the other components
              in the box; the Change  operation  must  be  called
              after  one  or more Removes to update the component
              positions.

       Glue(3I), Interactor(3I), Scene(3I), Shape(3I)