Written for all those who have to put up with the hockey-puck mouse supplied with the iMac and the Blue & White G3s.
Rotato is intended as a replacement for the Mouse control panel, and in addition to the usual settings for mouse speed and double click time, it lets you control the rotational status of the mouse, to compensate for a non-aligned mouse grasp characteristic.
In the spirit of MacHack, there are a few features of Rotato that make it worse than useless. The worst is that it only works on ADB devices, so won’t do you any good on a machine which actually uses one of the hockey-puck mice. Oh well, I thought the idea was cute.
Installation
Just throw the INIT and control panel in your system folder. They should be copied automatically to the appropirate places. You'll need to restart before you can control the mouse rotation.
How it works
At the heart of the INIT is an ADB service routine, that messes with data from the mouse before the system gets to see it. Specifically, it changes the horizontal and vertical deltas according to the angle preference. The ADB service routine, and an accompanying ADB Init
routine, lives in a PPC code fragment that is taken from the 'Smfr' resource by the INIT code. It communicates with the control panel by a small Ptr which is allcoated in the system heap, and whose address is available using the Gestalt selector 'Smfr'. The Control panel simply stuffs new angle values into these global prefs.
This hack does not patch any traps. It does seem to work on PowerBooks with a trackpad, too.
Acknowledgements
The ADB service routine code is based on code from ‘Reverse Mouse’, a hack from MacHack 1998 by Paul Baxter. I thank him for releasing the code for his hack. Thanks also to folks at Apple, for supplying something from which I could rip off some iMac mouse artwork (I can’t say what). Patrick Beard also supplied valuable information about writing PPC code resources.
Disclaimer
This hack was written in a short period of time, and has virtually no error checking. It may crash your machine. You use it at your own risk. Don’t blame me if it messes up your machine.
