Pointer gestures

WCAG 2.5.1 divides pointer input in two. A single-pointer gesture is one contact whose only significant fact is where it went down and came up: a tap, a click, a press and hold, a double tap. Everything else is either path based, where the route between those two points is what carries the meaning, or multipoint, where the number of contacts does. A swipe, a drag along a track, a circular scrub around a dial, a two-finger pinch, a three-finger swipe: all of these are gestures the criterion is about.

The rule is easy to state and easy to misread. It does not ban the gesture. It requires that whatever the gesture achieves can also be achieved with a single pointer, without a path and without a second finger. Keep the swipe and add the buttons. Keep the pinch and add plus and minus, or a double tap to fit. The gesture is usually the faster route for the people who can make it, and that is a good reason to keep it; the alternative is what makes the feature reachable for someone using a head pointer, an eye tracker, a switch, a mouth stick, or one shaky finger, all of which can put a pointer down in one place reliably and none of which can reliably trace an arc.

There is one exception, and it is narrower than people hope: the path is allowed to be essential when the path is the content. A signature pad, a freehand drawing tool, and a handwriting field cannot offer a button that draws for you. A carousel, a volume dial, a photo zoom, and a swipe action on a list row all can, so none of them qualify. The other common misreading is to count a long press as one of these; it is not, because holding still is not a path, though timing rules of their own apply to it.

Two practical notes. The alternative has to be visible and operable, not hidden behind the gesture it replaces, and a control that only appears on hover fails for the same population twice over. And platform-level gestures do not save you: a native pinch handled by the browser is fine because the browser also offers zoom controls, but a pinch you implemented in a canvas is yours to make reachable. If you are counting criteria, this one is Level A, which puts a swipe-only interface squarely in the category of things that do not ship.