ITI: read position progress bar

[bjalford]

Would like to implement a scroll bar to to indicate read position of AMP document.

Similar to this kind of thing: http://www.cssscript.com/demo/tiny-reading-progress-indicator-pure-javascript-rpbar-js/

Would anyone else find this useful? Any feedback before we start looking into coding?

[aghassemi]

@bjalford I think this UI will be useful in general. Instead of a dedicated component however, we could add support for such scroll-bound effect to #8411.

Currently #8411's design assumes one viewport scroll as duration of an effect, simply allowing users to pick "1 page scroll" instead of "1 viewport scroll" as duration can enable this and more.

#8411 is currently in progress, I recommend waiting until enough of scroll-bound animation work is in place and then evaluating whether this makes sense as a separate component or extending scroll-bound animation to support "1 page scroll" instead.

[bjalford]

Thanks. Makes sense.

[niutech]

Another solution is to use a pure CSS scroll depth indicator.

[mrjoro]

Is this I2I still active?

[tobiasfrenkler]

Very useful feature, especially for longer articles. I would love to see it implemented. Is it still under consideration?

[aghassemi]

@tobiasfrenkler a component for this is not prioritized but this is doable in AMP using amp-position-observer, here is an example: https://codepen.io/aghassemi/pen/MxQxZR?editors=1111

[aghassemi]

deduping with same request on #19193