explanation of "path-based gestures" for "single pointer"

[jake-abma]

https://www.w3.org/WAI/WCAG21/Understanding/pointer-gestures.html

Reading through 2.5.1 I see:

... can be operated with a single pointer without a path-based gesture, ...

So far clear, checking the definition for "single pointer" I see:

single pointer
pointer input that operates with one point of contact with the screen, including single taps and clicks, double-taps and clicks, long presses, and path-based gestures

https://www.w3.org/TR/WCAG21/#dfn-single-pointer

Why is the movement of a path based gesture also present here? It doesn't fit within the previous "one point of contact with the screen, including..."

Shortening the sentence:

pointer input that operates with one point of contact with the screen, including (...) path-based gestures.

1. I understand path-based gestures may be done with a single pointer, but can as well be done (or mandatory) with multi points.

2. The "one point of contact" can be read as: "only one point on the screen" not allowing hundreds of points when moving through a path

3. The "one point of contact" can be read as: "one point at a time, but this (one) point may change hundreds of times due to moving the pointer

Nr.1 should be clarified / scoped to single pointer

Nr.2 & 3 should be clear from the sentence, something like: "one point of contact with the screen and while holding down moving without releasing ..."

[patrickhlauke]

commented on #749 but fundamentally i think the definition itself is incorrect (it defines "single pointer gestures" rather than the more generic "single pointer"). this may well be the cause of the confusion/problem here.

to be clear, fundamentally what pointer gesture is getting at is: it's not a multi-touch/multi-pointer gesture (e.g. requiring two or more fingers on the screen), AND it doesn't involve following a specific path/track with that single pointer.

[detlevhfischer]

Agree the definition is incorrect, at least depending on the interpretation we favor. That's why I prefer the term 'single point activation'.
The term 'path-based' takes us back to the definition issue - is it any path of the single pointer across the surface, or just a path executing a straight swipe in one direction?
I have made my preference clear in #736 to which I invite comments...

[patrickhlauke]

note the definition of "pointer" in the Pointer Events specification

A hardware agnostic representation of input devices that can target a specific coordinate (or set of coordinates) on a screen, such as a mouse, pen, or touch contact.

https://www.w3.org/TR/pointerevents/#dfn-pointer

[edit: sorry, this is probably more relevant for #749 ... getting confused myself now with these interlocking issues]

as for "The term 'path-based' takes us back to the definition issue - is it any path of the single pointer across the surface, or just a path executing a straight swipe in one direction?" i would still say that it's anything that, to borrow from 2.1.1, "depends on the path of the user's movement and not just the endpoints" (so for me, even a slider that can ONLY be operated by moving the slider button, and does not allow single taps on the track of some arrow buttons, counts as using a gesture).

[detlevhfischer]

even a slider that can ONLY be operated by moving the slider button, and does not allow single taps on the track of some arrow buttons, counts as using a gesture).

@patrickhlauke I fully agree with that - for me it is the (lack of) ability to move the depressed pointer across the screen that counts. I think the hard-to parse phrase you quote from 2.1.1 tries to capture the fact that the path itself encapsulates a user intention - whether the gesture is intentionally presentational, as in signing a check (however imperfectly - we all know that from the touch screen onto which the delivery person asks us to scribble something, anything), or intentionally operational (as in dragging a slider thumb across the display, whether precisely or imprecisely (in the extreme, parabolically).

[alastc]

I think we bottomed this (path-based gestures) out in the update with #714, do the other participants here agree?

If not, is #749 substantively different? It has more comments, shall we close this and focus on that one?