EPUB navigator settles to a different position than the one requested with go().

[mickael-menu]

Bug Report

What happened?

When jumping (go()) to a given position, the EPUB navigator settles on a different position (a couple positions before or after) than the one requested.

Expected behavior

The user should reach precisely the requested position.

Environment

• Readium version: 2.3.0

Additional context

It's a tricky issue, because the progression for a position is computed differently in the position list and in the navigator. In the position list, it's a progression of bytes while in the EPUB navigator a scroll offset. As the progression takes precedence over position (because more precise) when resolving a locator, we end up in a different position.

It's unlikely we can fix the progression issue between bytes vs scroll offset. However, maybe the position list should not fill in the progression (as to let the position take precedence). Or the app could ask for a different resolution strategy on a case by case basis.

[vasikaran868]

@mickael-menu Is there any workaround for this issue?. I have been struck in this for past 2 days.

[mickael-menu]

No, I didn't have time to investigate this issue. Contributions are welcome if you find a workaround 😉