Expose consistent page-turn metadata for native swipe pagination

[atjackiejohns]

Hi.

I’m using foliate-view in a web reader and ran into an issue distinguishing native mobile swipe page turns from other relocation events.

For button/programmatic navigation, I can call view.next() / view.prev(), so my app knows the intended direction, and Foliate relocates with reason: "page".

For native touch pagination, Foliate handles the gesture internally:

touchend -> snap(vx, vy) -> #scrollToPage(page, "snap")

The consumer then sees relocate events with reason: "snap" and sometimes follow-up reason: "anchor" events. From the public event data, it is hard to tell whether the snap represented:

• a forward page turn
• a backward page turn
• settling back onto the same page
• a non-reading/layout relocation

Would you consider exposing consistent page-turn metadata for native swipe pagination, either on the relocate.detail for reason: "snap" or as a separate event?

For example:

{
  reason: "snap",
  direction: "next" | "prev" | "none",
  fromPage,
  toPage,
  pages,
  index
}

[johnfactotum]

I'm not sure what your use case is, but it never really made sense for the paginator to handle the touch events, anyway. scrollBy() and snap() were made public precisely so that one could handle gestures outside it.

[atjackiejohns]

Thanks. The use case is accurate reading-progress tracking. I count words after a successful forward page turn, so we need to distinguish forward, backward, and cancelled swipes.

I’d prefer to keep Foliate’s native swipe behaviour. Is there a recommended way to detect the result of a swipe, or should applications handle swiping entirely themselves?