Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!shelby!agate!usenet.ins.cwru.edu!ncoast!davewt
From: davewt@NCoast.ORG (David Wright)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Hooks into the OS vs doing it all yourself (Was Re: Clueless Mac<>)
Message-ID: <1991Feb4.054703.2506@NCoast.ORG>
Date: 4 Feb 91 05:47:03 GMT
References: <1991Jan25.075446.716@Neon.Stanford.EDU> <7658@sugar.hackercorp.com> <1991Jan31.011702.12095@Neon.Stanford.EDU>
Organization: North Coast Public Access Un*x (ncoast)
Lines: 38

In article <1991Jan31.011702.12095@Neon.Stanford.EDU> torrie@cs.stanford.edu (Evan J Torrie) writes:
>peter@sugar.hackercorp.com (Peter da Silva) writes:
>
>>>   Can your program get its hooks into this event BEFORE the OS gets
>>> hold of it and "do its own thing"?
>
>>Nope. You can tell Intuition the bounds you're willing to let the user manage
>>the window within, but that's it.
	He was wrong.
>
>  For example, all the hooks into window definition functions, menu
>definition functions, etc... where you can roll your own code, and
>make your own windows/menus etc... this is how the Mac gets all those
>nice NeXT/Motif type windows without having to rewrite existing
>program code.
	For an example of this on the Amiga, pick up any number of PD
programs that will let you change the appearance of the gadgets without
changing any program. And on the Amiga anyone is free to write a new
library that does whatever type of window trickery they wish, but most
people probobly won't like it.
>  Can you have callback functions.. i.e. get Intuition to call your
>function while it's moving the knob?
	I'm not sure, but I am almost certain from looking in the manual that
your program can receive "gadget moved" messages everytime the gadget moves
one notch, which would work functionally the same as a callback. The reason
you probobly need these on the Mac is that the Mac tends to treat gadgets
as a private thing, which return a certain value to the caller, and without a
call back function, you would not be able to do (extra) things while the
gadget was selected and being moved (in the special case of the scroll
bar, since most other gadgets on both systems return only the selected/
unselected type messages).
	The file requester provides a way to supply call back functions,
if you need to add more gadgets to the requestor for special purposes, or
you want to do things while the requester is pulling up a list of files,
for example, so I would assume that such a feature is provided elsewhere,
if needed.

				Dave