Touch

What a finger does today, and why @tap is the whole vocabulary.

A finger takes the same path as the mouse: it taps buttons and toggles, focuses inputs, drags a scrollbar thumb, drags out a text selection, and scrolls content directly when it grabs something that is none of those. A drag that stays inside the tap slop is still a tap.

Touch went a long time doing only the scrolling half, because there was no touch hardware here to try it on. It was found within a minute of the playground being opened on a phone, so treat "no hardware" as a reason to be suspicious of a path rather than a reason to call it done. In a browser the canvas also needs touch-action: none, or the page claims the gesture and the runtime never sees a drag.

Not done: no kinetic or inertial fling after the finger lifts, and no pinch zoom. Multi-touch is reported (see the pointer vocabulary below) but nothing in the runtime interprets a second finger yet.