Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!dewey.soe.berkeley.edu!oster
From: oster@dewey.soe.berkeley.edu (David Phillip Oster)
Newsgroups: comp.sys.mac
Subject: Re: Graphics Tablet..? Help!
Message-ID: <31968@ucbvax.BERKELEY.EDU>
Date: 17 Oct 89 07:59:16 GMT
References: <2745@harrier.ukc.ac.uk>
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: oster@dewey.soe.berkeley.edu.UUCP (David Phillip Oster)
Organization: School of Education, UC-Berkeley
Lines: 35

I've written tablet drivers for Macintosh for a living. Here are some of
the issues:
1.) How fast is the data rate from the tablet? Most tablets I've seen seem
sluggish compared to the mouse.
2.) How sensitive is the tablet to the angle of the pen? Many tablets
requirw you to hold the pen always at the same angle or the cursor moves.
3.) How sensitive is the tablet to stray fields? I've seen
tablets that get inaccurate when you shift them a few degrees, due to
interaction with the local magnetic field.  I've seen other tablets that
were built with out recognizing that the human body makes a good raio
antenna. (on one brand, you can hold the digitizing pen in one hand, and
fingerpaint with the index finger of your other hand. The positioning
signals just travel through the body. This means that when the tablet is
used normally, the amount of hand pressure on the tablet affects where the
cursor is.
4.) How flexible is the software for specifying coordinate systems? My
dirvers allow arbitrary rotation and scaling, with a dialog button to
press to "preserve aspect ratio" that is, scale the x and y coordinates
equivalently, so a square on the tablet translates to a square, not a
rectangle, on the screen.
5.) Does the software have an easy way of getting into mouse mode? If you
have a big tablet, it is a pain to stretch all the way across it to get at
the menu bar. You should be able to flip the system into mouse mode, and
ideally have the same kind of mouse acceleration that the normal mouse
provides.
6.) What kind of macro package does the tablet support? You'll want quick
ways of doing menu commands by pointing at reserved areas of the tablet.
This lets you get more work done without taking your fingers off the
digitizing pen.
7.) How does the tablet interface to the Mac? Serial tablets take up one
of two valuable serial ports on a Mac. People with machines newer than the
MacPlus generally prefer ADB tablets, although they are often more
expensive.

Conclusion: arrange for a test drive before you buy. Good hunting.