IEEE P1201.1 Layered Window System API

David J Bryant djb at
Wed May 1 12:25:53 AEST 1991

Submitted-by: djb at (David J Bryant)

Shane McCarron (ahby at uinj.UI.ORG) writes (in response to a question from
Peter da Silva):

Shane:...are portable to a number of platforms (the P1224 [sic] approach is to
	have a layered API which would work on MS-DOS, OSF/Motif, OPEN LOOK,
	and Presentation Manager).
Peter: How about MacOS/Finder, GEM, and Intuition?
Shane: I believe that MacOS/Finder was included.  GEM and Intuition were 
	not, as far as I know.  Could someone else from 1201 address this?

Sure, I'm from P1201.1 (or at least I've recently taken to dwelling there 
one week per quarter).  P1201.1's current working requirements for a 
Layered API (LAPI) specify that it must be implementable on top of OSF/Motif, 
Open Look, Macintosh, Windows 3.0 and Presentation Manager.  I don't reall 
mention of GEM or Intuition in any of the meetings I've attended or read 
minutes from.  Note that this requirement wouldn't preclude support of GEM, 
Intuition or others in any specific P1201.1 standard-conformant 
implementation.  (For example, at least one current LAPI product provides 
support for curses/terminfo.) 

Peter: Does your API require the application to manage its own refresh events,
	or is that stuff hidden far enough in the library that windowing systems
	that handle that sort of thing through backing store won't lose out?

Shane: The whole point of a LaFI API is that the policies of the underlying
	GUI are hidden from the application developer.  That should all sort
	os the autonomic behaviors that windowing systems have (just as the
	human body breathes and pumps blood without conscious effort).

True.  I'm not sure that comp.std.unix is the place to go much into this 
(wanna come to a P1201.1 meeting?).  Naturally there's a fair amount of 
technical wizardry in managing this kind of thing for five very different 
underlying windowing system, but this it is indeed the intent, and there
are several current products that demonstrate it to be feasible.

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Volume-Number: Volume 23, Number 56

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