OS X Lion’s Gesture Language
OS X Lion interprets mouse and trackpad gestures as commands. Those commands are actually a language. They have a vocabulary and a grammar. Here’s my theory.
Grammar
In Lion’s gesture language, each gesture is an imperative sentence, composed of a verb and an object. You do a gesture by making a motion or some number of taps. In so doing you use some number of fingers. The number of taps is the verb in the sentence, indicating what action should happen. The number of fingers is the direct object, indicating what the action should be done to.
Vocabulary
If you just move the mouse or swipe the trackpad, that’s zero taps, and it means “move”. One tap (or click) is “use”. Two taps is something like “show me”. On a Magic Mouse, if you use one finger on the touch surface, that’s “the window content”. Two fingers means “the Spaces”, as they relate to the viewport. Zero fingers (not utilizing the Magic Mouse’s touch surface, but using your whole hand) means “the pointer” or the object under the pointer. On a trackpad, you would use one additional finger in each of these cases.
Rosetta Stone
So the gesture language is as follows, assuming a Magic Mouse. For a trackpad, add one finger:
- Motion with no fingers: Move the pointer. “Point”.
- Motion with one finger: Move the window content. “Scroll”.
- Motion with two fingers: Move the Spaces. “Change Spaces”.
- One tap/click, no fingers: Use what’s pointed at. “Select”.
- One tap, one finger: Do nothing.
- One tap, two fingers: Do nothing.
- Two taps/clicks, no fingers: Show me what’s pointed at. “Open”.
- Two taps, one finger: Show me the window content. “Zoom”.
- Two taps, two fingers: Show me the Spaces. “Mission Control”.
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Languages must be practical. There are more gestures than these, and there are special cases and exceptions. On a trackpad, Mission Control is actually activated by a three-finger upward swipe, which is easier than a three-finger double-tap. The Launchpad pinch gesture is another outlier. As for the two gestures that do nothing, it’s good that they do nothing. It’s too easy to do them by accident.
You may have been using this language without noticing how it was structured. But this structure makes it easy for your fingers to learn it. So it’s no wonder that Lion’s gestures feel natural after just a few hours.
As for Lion’s new scroll direction, I encourage you to try it for a week. After using it for some time now, I think “natural” was the right name for it.
In summary:
- Taps = Verbs = [0, 1, 2] = [move, use, show me]
- Fingers = Direct Objects = [0, 1, 2] for Magic Mouse or [1, 2, 3] for trackpad = [pointer/object, window/content, viewport/Spaces]
- Taps × Fingers = Verbs × Objects = [ [Point, Scroll, Change Spaces], [Select, n/a, n/a], [Open, Zoom, Mission Control] ]
