zeus/src/AlbumVBT.i3

 Copyright (C) 1990, Digital Equipment Corporation.         
 All rights reserved.                                       
 See the file COPYRIGHT for a full description.             
 Last modified on Tue Jan 26 09:20:57 PST 1993 by mhb      
      modified on Thu Sep 24 11:51:56 PDT 1992 by steveg   

<* PRAGMA LL *>

 AlbumVBT manages a photo album of snapshots of VBTs.  The
   snapshots are taken by Image.FromVBT. 


INTERFACE AlbumVBT;

IMPORT Axis, VBT;

TYPE
  T <: TPublic;
  TPrivate <: VBT.Split;
  TPublic = TPrivate OBJECT
            METHODS
              <* LL <= VBT.mu *>
              init (layoutAxis   : Axis.T;
                    size         : CARDINAL;
                    width, height: REAL       := 30.0): T;

              <* LL = VBT.mu *>
              add   (w: VBT.T);
              clear ();
            END;

 The call v.init(layoutAxis, size, width, height) initializes
   v to be an AlbumVBT.T.  An AlbumVBT.T is a VBT.Split
   that manages the layout of a series of images produced by
   taking snapshots of VBTs using Image.FromVBT.  The images in v
   are all shaped v.width by v.height millimeters and laid
   out in a grid.


   If v.layoutAxis is horizontal, then there are v.size
   images laid out horizontally in each row, with rows laid out
   top to bottom.  If v.layoutAxis is vertical, then there are
   v.size images per column and the columns are laid out left
   to right.


   The method call

      v.add(w)
   

adds a new snapshot to the album.  It occupies the next slot
   either vertically or horizontally (depending on
   v.layoutAxis).


   The method call

      v.clear()
   

removes all snapshots from the album. 


END AlbumVBT.