Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!columbia!rutgers!caip.rutgers.edu!peskin From: peskin@caip.rutgers.edu (R. L. Peskin) Newsgroups: comp.lang.smalltalk Subject: MVC question Message-ID: <4282@caip.rutgers.edu> Date: Wed, 1-Jul-87 12:13:03 EDT Article-I.D.: caip.4282 Posted: Wed Jul 1 12:13:03 1987 Date-Received: Thu, 2-Jul-87 05:47:20 EDT Reply-To: peskin@caip.rutgers.edu (R. L. Peskin) Distribution: world Organization: Rutgers Univ., New Brunswick, N.J. Lines: 23 An interesting? question comes up in the following MVC application: Assume a model has two views. Normally model changes will register in both views. If however, one of the view is covered by another (unrelated) window, and the model continues to change, the uncovered view will update in a normal manner. The covered view when uncovered will show a state prior to changes before its covering. Any activation of the view, i.e. move it, frame it, etc. will result in immediate update. This behavior occurs on the Sun PS and Tektronix implementations, but not on the Xerox 1108 implementation. It appears that on the Sun and Tek versions, when a view is covered, it is saved as of its last active state; and when re-exposed it is not actually redrawn. Perhaps the Xerox implementation always redraws? Does anyone have the correct explanation for this, and more important, how to get around the problem? We are doing a full two and three dim. general graphics utility in smalltalk, and need multiple views that behave normally even when uncovered. We want to avoid implementation dependant features. --dick peskin CAIP Parallel Computer Lab Rutgers University