By default, the Apple Magic Trackpad has way more horizontal sensitivity than vertical sensitivity, leading to weird results on wide screens and multiple monitor setups. This means that while you can span 1920 pixels with one horizontal swipe, you can't pan 1/3 of the 1080 pixels with one vertical swipe.
The attached patch sets the horizontal and vertical resolution to be the same so that when you draw a circle on the track pad, you see a similar shape drawn by the mouse. Patch should either go into /usr/share/X11/xorg.conf.d/ or into /etc/X11/xorg.conf.d/. You must restart X in order to see changes with the touchpad. I'm preparing a similar patch for the Apple MacBook Pro built-in touch pad.
ProblemType: Bug
DistroRelease: elementary OS 0.2
Package: elementary-desktop 1.287-0~361~precise1 [origin: LP-PPA-elementary-os-daily]
ProcVersionSignature: Ubuntu 3.2.0-34.53-generic 3.2.33
Uname: Linux 3.2.0-34-generic x86_64
NonfreeKernelModules: nvidia wl
ApportVersion: 2.0.1-0ubuntu15+elementary3~precise1
Architecture: amd64
CrashDB: elementary_meta
Date: Mon Dec 10 21:52:30 2012
InstallationMedia: elementary OS 0.2 "Luna" - Beta 1 amd64 (20121114)
MarkForUpload: True
ProcEnviron:
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: elementary-meta
SuspiciousXErrors:
ThirdParty: True
UpgradeStatus: No upgrade log present (probably fresh install)
I think it's better to get the patch applied upstream, in Ubuntu, so that the fix reaches a greater number of people.
Thanks a lot for the fix!