vbtkit/src/lego/ZMoveVBT.i3

 Copyright (C) 1992, Digital Equipment Corporation                         
 All rights reserved.                                                      
 See the file COPYRIGHT for a full description.                            
                                                                           
 Last modified on Fri Jun 11 16:01:24 PDT 1993 by meehan                   
      modified on Mon Feb  1 23:14:08 PST 1993 by mhb                      
      modified on Tue Jun 16 13:07:57 PDT 1992 by muller                   
      modified on Fri Mar 27 02:12:27 1992 by steveg                       

<* PRAGMA LL *>

 A ZMoveVBT is a switch that has the side-effect of
   repositioning its nearest ancestor subwindow.


   If the initial mouse click is unshifted, the subwindow is
   lifted to the top of its sibling; otherwise, the subwindow
   keeps its current top-to-bottom ordering among its siblings.
   As the mouse is moved, the cursor is changed to give
   appropriate feedback, and an outline of the subwindow is moved
   to show where it will be repositioned on an uncancelled
   upclick.  On an uncancelled upclick or chord-cancel, the
   outline is removed. 


INTERFACE ZMoveVBT;

IMPORT Rect, SourceVBT;

TYPE T <: SourceVBT.T;

 The following procedure is useful for subclasses, such as ZGrowVBT,
   to control the shape of the outline of v's subwindow as the
   mouse is being dragged. 


PROCEDURE MoveAndHighlight (v: T; READONLY rect: Rect.T);
<* LL = VBT.mu *>

 Show the outline of v as rect.  Should only be called by the
   during method of a subclass. 
 The default during method calls MoveAndHighlight with
   rect equal to the domain of the subwindow being moved,
   translated by an appropriate amount to reflect the mouse
   movement since the initial mouse click.


   On an uncancelled upclick, the default post method moves the
   subwindow to the rectangle last specified to
   MoveAndHighlight and calls ZChildVBT.Moved and
   ZChildVBT.Grew.


   The highlighter used for displaying an outline of the
   subwindow contain v is the HighlightVBT returned by
   SourceVBT.GetHighlighter(v).  An appropriate paint op is
   constructed by examing the colors of the background child of
   the subwindow's parent.  Those colors are found using the
   VBTColors interface; be sure to use that interface to
   record the background child's primary foreground and background
   colors. 


END ZMoveVBT.