CLIM mail archive


Re: Moving objects and incremental redisplay

    Date: Tue, 28 Sep 1993 15:45 EDT
    From: Scott McKay <>

	Date: Tue, 28 Sep 1993 14:40 EDT
	From: Curt Eggemeyer <>

	Maybe in CLIM version 3 ... the incremental display facility would have
	an option of working with either a top-down (as it is now) or a bottoms-up
	way. Many of my particular display domains would really exploit the
	bottom-up capability if it were there.

    Can you design a language that specifies how the program tells CLIM
    about this?  I'm serious.

    The big problem is, quite simply, that incremental redisplay is a
    *really hard* problem.  It's easy to think of a bunch of special cases:
    the Emacs redisplay special case, the line-at-a-time special case, the
    simple graphical editor special case, the spreadsheet special case.  And
    it's easy to write code to implement any of these well.  It's relatively
    easy to specify the general case -- that's what UPDATING-OUTPUT does.
    But it's hard to implement that well, and it's hard to figure out from a
    general specification which of the special cases you might fall into.

Why not just make the special cases available?  Couldn't this be a
declaration at some level?  At the very least, there could be a library
of fill-in-the-blanks template implementations for the special cases.
I'd guess that the special cases would cover the usual 80%.

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