Copyright (C) 1994, Digital Equipment Corp.
<* PRAGMA LL *>
<* PRAGMA SUBTYPE *>
A MarginFeedbackVBT
is a multi-filter feedback that provides
visual feedback to the left of another VBT. This interface
defines a handful of useful ``left-hand sides.''
INTERFACE MarginFeedbackVBT;
IMPORT FeedbackVBT, Shadow, VBT;
TYPE
<* SUBTYPE T <: MultiFilter.T *>
T <: Public;
Public = FeedbackVBT.T OBJECT
METHODS
<* LL.sup <= VBT.mu *>
init (ch, marginVBT: VBT.T): T
END;
The following procedures create some popular types of
MarginFeedbackVBT
s. See Figure~\ref{fig:marginfeedbacks}.
PROCEDURE NewCheck (ch: VBT.T; shadow: Shadow.T := NIL): T;
<* LL.sup <= VBT.mu *>
PROCEDURE NewBox (ch: VBT.T; shadow: Shadow.T := NIL): T;
<* LL.sup <= VBT.mu *>
PROCEDURE NewBullet (ch: VBT.T; shadow: Shadow.T := NIL): T;
<* LL.sup <= VBT.mu *>
END MarginFeedbackVBT.