<* PRAGMA LL *>
<* PRAGMA SUBTYPE *>

A ZChildVBT is a subclass of a HighlightVBT that insulates any highlighting done in the ZChildVBT from highlighting done in other subwindows. Clients should use a ZBackgroundVBT around the background child in order to insulate highlighting in the background child from highlighting in the subwindows.

There are two alternate ways to initialize a ZChildVBT. Each allows the client to specify whether the subwindow should be initially visible (``mapped'') and how the subwindow should be reshaped when the parent ZSplit is reshaped.

The method call v.init(...) allows the client to specify where the center or a corner of v should be placed, relative to the parent, either in absolute distance (in millimeters) from the parent's northwest corner (CoordType.Absolute), or as percentages of the parent's width and height (CoordType.Scaled). The default is to align the center of v with the center of the parent. The size of v is its preferred sizes in both the horizontal and vertical dimensions.

The method call v.initFromEdges(...) allows the client to specify the edges of v, either in absolute distance (in millimeters) from the parent's northwest corner (this is the only case in which the client specifies the absolute size of v), or as percentages of the parent's width and height.

The implementation will not pop up a subwindow with its northwest corner north or west of the visible portion of the ZSplit parent; it will override the specified position as necessary to bring it into view. It is a checked runtime error to specify scaled coordinates (percentages) that are outside the range 0.0--1.0. If the specified position is overriden, or if the subwindow is not entirely visible when the subwindow is first made visible, the implementation will also override the reshape method so that the subwindow will be repositioned using the information specified when it was initialized.

Finally, in order for the reformatting to meet specifications above, the client must call Inserted after the subwindow is inserted as a child of a ZSplit; the client must call Moved after the subwindow is repositioned by the user; and the client must call Grew after the size of the subwindow is changed by the user.

INTERFACE ZChildVBT;

IMPORT HighlightVBT, VBT, ZSplit;

TYPE
  Location = {NW, NE, SW, SE, Center};
  CoordType = {Absolute, Scaled};
  T <: Public;
  Public = HighlightVBT.T OBJECT
           METHODS
             <* LL <= VBT.mu *>
             init (ch  : VBT.T;
                   h, v          := 0.5;
                   loc           := Location.Center;
                   type          := CoordType.Scaled;
                   shaper: ZSplit.ReshapeControl := NIL;
                   open: BOOLEAN                 := TRUE): T;
             initFromEdges (ch: VBT.T;
                            w, e, n, s: REAL;
                            type := CoordType.Absolute;
                            shaper: ZSplit.ReshapeControl := NIL;
                            open := TRUE): T;
           END;

PROCEDURE InitiallyMapped (v: VBT.T): BOOLEAN;

If v is a ZChild, return the value of open when it was initialized. Otherwise, return TRUE.

PROCEDURE Pop (v: VBT.T; forcePlace := FALSE);

Map v and lift it to the top of its parent's children. If forcePlace is set, position v at its initial location.

PROCEDURE Inserted (v: VBT.T);

The client must call this procedure after v has been inserted into a ZSplit. This procedure sets a ReshapeControl object on v. If v isn't a ZChildVBT, the ReshapeControl tries to center v, subject to the contraint that its northwest corner is just visible. If v is a ZChild, the ReshapeControl will follow vbt's initial position until v is moved by the user (usually because Moved is called). At that point, the northwest corner of v will remain at that position relative to its parent, until the user moves it again.

PROCEDURE Moved (v: VBT.T);

The client must call this procedure after v has been moved by a user. If v is a ZChildVBT, this procedure notes that v has been moved by the user, so that the next time it is reshaped, v will retain its current position relative to its parent. If v isn't a ZChildVBT, this procedure is a no-op.

PROCEDURE Grew (v: VBT.T; w, h: INTEGER);

The client must call this procedure after the size of v has been changed to w-by-h (in pixels) by a user. If v is a ZChildVBT, this procedure notes that v has a new shape and calls VBT.NewShape to tell the parent ZSplit. Subsequently, v will report its shape as w-by-h. If v is not a ZChildVBT, this procedure is a no-op.

VAR (*CONST*)
  Scaled: ZSplit.ReshapeControl;
  ScaledHFixed: ZSplit.ReshapeControl;
  ScaledVFixed: ZSplit.ReshapeControl;
  ScaledHVFixed: ZSplit.ReshapeControl;

END ZChildVBT.