Path: utzoo!attcan!uunet!cbmvax!jesup
From: jesup@cbmvax.UUCP (Randell Jesup)
Newsgroups: comp.sys.next
Subject: Re: Next and the competition
Message-ID: <5589@cbmvax.UUCP>
Date: 28 Dec 88 23:22:49 GMT
References: <29866@tut.cis.ohio-state.edu> <5567@cbmvax.UUCP> <361@internal.Apple.COM>
Reply-To: jesup@cbmvax.UUCP (Randell Jesup)
Organization: Commodore Technology, West Chester, PA
Lines: 30

In article <361@internal.Apple.COM> casseres@Apple.COM (David Casseres) writes:
>In article <5567@cbmvax.UUCP> daveh@cbmvax.UUCP (Dave Haynie) writes:
>>Aargh!! No, no!  Please don't say that this system doesn't support "SMART" 
>>refresh windows!  This is supposed to be a "real" computer with lots of
>>memory.  If the application doesn't know how to refresh a window, it
>>shouldn't have to.  Let the OS handle all aspects of a window.

>Gee, just what are "all" aspects of a window?  Should the OS also do the
>selection and highlighting of objects in the window when the user clicks
>the mouse?  Maybe it should guess what the application wants to draw in
>the window, and do the drawing?  After all, refreshing a window does in-
>volve drawing its content.  Or maybe you mean that refreshing should only
>be done by saving the bits of the window's current image, then restoring
>them when a refresh is needed.  Too bad if the content of the window wanted
>to change before the refresh.

	You misunderstand.  By "Smart Refresh" windows, Dave means windows
in which off-screen portions are saved.  Drawing to off-screen areas goes into
those saved areas, so if that window is uncovered, the display is up to date
VERY fast compared to most applications redrawing through a damage list.

	It turns out nExt has something similar, but the off-screen bitmap
is the size of the window.  Eats memory, but they burn memory like there's
no tomorrow.  Amigas have something similar, called SuperBitMap windows, where
there's an off-screen bitmap, but the bitmap can be larger than the window,
and can be scrolled (relative to the window).  The window is a window into
a larger display.

-- 
Randell Jesup, Commodore Engineering {uunet|rutgers|allegra}!cbmvax!jesup