One of the neat features that debuted with the MacBook Air (and is now available on the latest MacBook Pro models, as well) is the multi-touch trackpad. Using multiple-finger gestures similar to those you use on an iPhone’s touchscreen, this new trackpad lets you perform actions unavailable with older models.
For example, you can “pinch” two fingers together to zoom out from an image in iPhoto or Preview, or spread those two fingers apart to zoom in. You can place two fingers on the trackpad and rotate them to rotate an image on the screen. Or you can swipe three fingers across the trackpad to navigate between photos in iPhoto and Preview or tabs in Safari.
Unfortunately, the usefulness of this new trackpad feature is limited by the fact that it doesn’t work in every program. I can think of plenty of other programs that could benefit from this functionality.
Will Henderson’s MultiClutch, currently at beta version b5, gives you that flexibility by extending multi-touch gestures to other programs. After installing MultiClutch, a new MultiClutch pane in System Preferences lets you assign each gesture to any action that has a keyboard shortcut.
You can assign global gestures, which affect all programs, or program-specific gestures, which override global gestures in that specific program. For example, you can globally assign Zoom Out—pinching two fingers together—to Command+W (Close Window), but assign that gesture to the actual Zoom Out command in Preview.
Unfortunately—or fortunately, depending on your point of view—MultiClutch doesn’t preserve built-in gestures in programs that support them (for example, iPhoto, Preview, and Safari). If you configure a Global shortcut for a particular gesture, that setting will override any built-in gesture unless you set up application-specific gestures for the affected program(s).
The gestures you can assign include three-finger swipe (left, right, up, or down); rotate (right or left); and zoom (in or out). There are also two “combo” gestures: zoom out and then in, and zoom in and then out; you perform these gesture using one fluid motion.
To give you an idea of how you might use MultiClutch, I've added gestures for Safari so that Zoom In increases text size; Zoom Out closes the current tab; Swipe Right or Left switches to the next tab to the right or left, respectively; and the Zoom Out/In combination creates a new tab. I’ve also set Zoom Out as a global gesture for Command+W, so I can close the current window in any program by simply pinching two fingers together; and Swipe Down is set to minimize the current window to the Dock—a rather intuitive gesture, in this case.
Another very cool use of MultiClutch is to switch between workspaces when using Leopard’s Spaces feature. A simple three-fingered swipe—up, down, left, or right—“swipes aside” the current workspace to switch to a different one. However, there’s a trick to setting this up: You have to use the Exposé & Spaces pane of System Preferences to first set your space-switching shortcut to something other than your preferred shortcut; then set up MultiClutch’s gestures to use the desired keyboard shortcuts; and, finally, go back and change Spaces to the desired shortcuts. If you don’t use this procedure, each time you try to assign the current space-switching shortcuts in MultiClutch’s preferences, Spaces will intercept the shortcut and switch spaces.
One feature I’d like to see as MultiClutch’s development progresses is a way to disable particular gestures in particular contexts. For example, my biggest beef with the multi-touch trackpad on the MacBook Air is that if the Desktop is active, accidentally using one of the pinch gestures (in or out) resizes and repositions Desktop icons. I’d love to be able to disable zoom gestures altogether when the Finder is active.
I’d also like to see some sort of “minimum gesture movement” setting so that accidentally touching the trackpad with multiple fingers isn’t interpreted as a gesture. I’ve occasionally closed a window I didn’t mean to close because I’ve touched the trackpad with two fingers and the trackpad thought I was performing the “pinch” motion.
Note that MultiClutch installs an Input Manager module, which means, in this case, that it’s using an unsupported method to add its functionality. I personally use the occasional Input Manager hack on my own Macs without problems, but if you start experiencing issues with your Mac, especially after upgrading OS X or Safari, Input Managers are a good place to start troubleshooting. (This Input Manager approach also means that MultiClutch may not work with some Carbon applications.)
MultiClutch b5 requires Mac OS X 10.5 and a Mac laptop with a multi-touch trackpad.