Date: Thu, 6 Mar 2008 19:09:50 +1030 From: "Daniel O'Connor" <doconnor@gsoft.com.au> To: freebsd-current@freebsd.org Cc: Chuck Robey <chuckr@chuckr.org> Subject: Re: how to design a tablet driver? Message-ID: <200803061909.58538.doconnor@gsoft.com.au> In-Reply-To: <47CF4AFD.5050708@chuckr.org> References: <47CF4AFD.5050708@chuckr.org>
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--nextPart1376973.DoBbveX7Oq Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Thu, 6 Mar 2008, Chuck Robey wrote: > My current project is making a usb driver for my "Superpen" WP8060 > Tablet. It's a cheaper version of the better known Wacom Tablet, > which i couldn't afford for my use in Gimp. I figure, I better ask > myu questions here, because they don't really bear so much on usb as > they bear upon the basic architecture of a mouselike drvice that must > be absolute, not relative, in approach. I would say that you should report the physical size of the tablet, and=20 then report movement in terms of real physical units. You could do all=20 this in fixed point 32 bit ints and then have an enum which says what=20 units it's reporting in (tenths of a millimetre, or whatever). After that it's up to the client to do the right thing. Passing screen=20 size to the display drive seems like a gross hack liable to much=20 breakage. All this said I suspect that this problem has already been solved by=20 other tablet drivers so I'd look there. Not to mention that there=20 should already be a protocol for tablets that goes between the kernel=20 and X (or from an X driver that opens ugen and speaks to the rest of X) > OK, that means that I have to know the graphic point size (is there a > Well, if it does, then it also means that I need to find the > absoluite point size of whatever screen you're playing with, no > matter if I'm talking about an X11 screen or a screen from a vty. I > mean, vty's use mice now, isn't it possible for use a tablet on a > vtyt also? OR, extra possibility, maybe if we're in a non-X11 > environment, fall back to a relative use, and only go to absolute > when you go to X11. If I have too much trouble getting and keeping > an idea of the screen size oout of X11, I could do that. Personally, I'd forget about vty's unless you want to do mouse emulation=20 stuff there.. I imagine it would be a pretty major rearchitecting of=20 sysmouse, moused etc etc.. Too hard to for too little reward :) > I'm suggesting this because I'm very, very confused as to how I would > figure out what the screen size is for a vty. If I gotta do a > absolute gig on a bty, then I gotta find some way to ask the size of > the cry, and get me driver in the list of those to be notified if the > size of a vty changes. As above - basically "don't bother". > Please, if you have any comment, feel free to interrupt all over me, > sir! The sooner I get some of this, the sooner that really cheap > (~$60) 8"X6" tablet is ours, especially for Gimp. Wow, pretty nice :) I might see if I can grab one.. =2D-=20 Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C --nextPart1376973.DoBbveX7Oq Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQBHz63e5ZPcIHs/zowRAogAAJsFnfUjYZwV8xHtoFMCDuy8/p+bnQCfe6vM qNBYVkCe8yxAwQsQgVkF31s= =pxib -----END PGP SIGNATURE----- --nextPart1376973.DoBbveX7Oq--
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