Copyright 1992 Digital Equipment Corporation.
Distributed only by permission.
Last modified on Thu Feb 11 17:52:23 PST 1993 by johnh
modified on Tue May 12 08:37:40 1992 by mhb
INTERFACE ViewClass;
IMPORT Thread, View;
TYPE
TT = View.Public BRANDED OBJECT
name : TEXT := NIL;
alertable : BOOLEAN;
evtHandler: Thread.T;
evtCond : Thread.Condition;
evtArg : REFANY;
evtHandled: BOOLEAN;
evtHQuit : BOOLEAN := FALSE;
END;
The name field is set by Zeus immediately after a View.T has been
instantiated. Thereafter, the field is read-only.
The alertable field is set by Zeus immediately after a View.T has
been instantiated. Thereafter, the field is read-only. This field
indicates whether the view is willing to receive alerts to tell it to
stop processing the current event.
The evtHandler field is a worker thread tickled by Zeus to process
each output event when it occurs. evtCond and evtArg are used in the
coroutines for output event procesing.
The evtHandled field is set to FALSE by the default output event
methods. User-provided event handlers will not see this field, and
hence will not set it. The event dispatcher uses this field to decide
whether an event was handled by any view.
The evtHQuit field is used by Zeus to tell the evtHandler thread to
terminate.
REVEAL View.T <: TT;
<*PRAGMA LL*>
PROCEDURE Activate (v: View.T; on: BOOLEAN);
<* LL = VBT.mu *>
(* Activate the view if on is TRUE; o/w set it to a gray texture. *)
END ViewClass.