Xref: utzoo comp.sys.amiga.programmer:4312 comp.sys.amiga.misc:4388
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!peter
From: peter@cbmvax.commodore.com (Peter Cherna)
Newsgroups: comp.sys.amiga.programmer,comp.sys.amiga.misc
Subject: Re: My Tablet Program Broke
Message-ID: <22252@cbmvax.commodore.com>
Date: 7 Jun 91 19:05:48 GMT
References: <1991May30.072335.9941@netcom.COM> <1991May31.022526.24625@monu0.cc.monash.edu.au> <1043@celia.UUCP>
Reply-To: peter@cbmvax.commodore.com (Peter Cherna)
Organization: Commodore-Amiga, Inc.  West Chester, PA.
Lines: 38

In article <1043@celia.UUCP> celia!neil@usc.edu (Neil Richmond) writes:
>I wrote a tablet driver program for my Kurta tablet to run on my A2000 under
>1.3. The problem is that when I got my A3000 with 2.0, my program broke. I
>have checked all phases of my program and the problem seems to occur when I
>access the input.device. A couple of notes, I use IECLASS_POINTERPOS instead
>of RAWMOUSE.

The 1.3 RKM manual states explicitly that you must not rely on data you
place in an InputEvent remaining unmodified for your later use (see
p. 698).  It turned out that under 1.3, the contents of IECLASS_POINTERPOS
happened to be preserved.  For compatibility, recent versions of 2.0
now preserve those fields as well.

A second issue is that the include files have defined the mouse-button
codes (IECODE_LBUTTON, etc.) as being for the IECLASS_RAWMOUSE event,
but many people sent them (incorrectly) for IECLASS_POINTERPOS.  Under
1.3, that happened to work (because IECLASS_POINTERPOS was coverted
very simply into IECLASS_RAWMOUSE).  Under 2.0, the handling of input
events is more sophisticated, and this side-effect was lost.  Again,
because of the number of people who depended on this and the fact
that the side-effect could be easily re-created without much burden
to Intuition, a change was made so things work like they did in 1.3.

In any case, the last public release of 2.0 (2.03) still has this
problem.  You'll have to wait (not long, hopefully) for 2.04 to
cure this problem.

Alternately, since you wrote the driver, you could fix it to
tide you over in the meantime.

>neil

     Peter
--
Peter Cherna, Operating Systems Development Group, Commodore-Amiga, Inc.
{uunet|rutgers}!cbmvax!peter    peter@cbmvax.commodore.com
My opinions do not necessarily represent the opinions of my employer.
"If all you have is a hammer, everything looks like a nail."