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AMP doesn't implement scrolling in software. It is native GPU accelerated scrolling. iOS does have 2 modes and it might be that AMP hits the one some people don

AMP doesn't implement scrolling in software. It is native GPU accelerated scrolling. iOS does have 2 modes and it might be that AMP hits the one some people don't like. Edit: Filed https://github.com/ampproject/amphtml/issues/5125 https://github.com/ampproject/amphtml/issues/5125 to see if AMP can switch to other GPU scrolling mode.

Touche 10y ago
Why does AMP do anything with scrolling at all?
- JohnDotAwesome 10y ago
  Knowing where the viewport is relative to the document is pretty valuable; It means that AMP can defer loading potentially sluggish content until the viewport lands on a particular position.
  - Touche 10y ago
    Sounds like a premature optimization to me. The websites I tried did not have such requirements but the scrolling was just as janky nonetheless.
    - stonogo 10y ago
      It's not premature optimization. It's optimization for ad revenue; they can charge more if they can prove an advertisement is visible on screen.
  - deleted 10y ago
    [deleted]
- cramforce 10y ago
  This is just CSS which exists for unrelated reasons.
- idlewords 10y ago
  For surveillance and user tracking.
  - cramforce 10y ago
    Even if this would be correct (which it is not), it would only require to observe, not influence scrolling.
    - idlewords 10y ago
      Maybe not in version 1. Think bigger, you'll get that promotion!
MBCook 10y ago
I'm with touche. Why in the world is AMP telling iOS to do scrolling different from other pages? What's the benefit? Why bother?
- untog 10y ago
  IIRC the iOS UIScrollView has a different scroll behaviour when it's inside a UIWebView. So they might have reset that difference.
- cramforce 10y ago
  Everything scroll related is in CSS. The long explanation is here https://medium.com/@dvoytenko/amp-ios-scrolling-and-position-fixed-b854a5a0d451 https://medium.com/@dvoytenko/amp-ios-scrolling-and-position...
  - Touche 10y ago
    I'm well aware of how janky position: fixed on mobile. The solution is not to use position: fixed, not to try to "fix" it and make the experience bad.

Touche 10y ago

Why does AMP do anything with scrolling at all?

JohnDotAwesome 10y ago
Knowing where the viewport is relative to the document is pretty valuable; It means that AMP can defer loading potentially sluggish content until the viewport lands on a particular position.
- Touche 10y ago
  Sounds like a premature optimization to me. The websites I tried did not have such requirements but the scrolling was just as janky nonetheless.
  - stonogo 10y ago
    It's not premature optimization. It's optimization for ad revenue; they can charge more if they can prove an advertisement is visible on screen.
- deleted 10y ago
  [deleted]
cramforce 10y ago
This is just CSS which exists for unrelated reasons.
idlewords 10y ago
For surveillance and user tracking.
- cramforce 10y ago
  Even if this would be correct (which it is not), it would only require to observe, not influence scrolling.
  - idlewords 10y ago
    Maybe not in version 1. Think bigger, you'll get that promotion!

MBCook 10y ago

I'm with touche. Why in the world is AMP telling iOS to do scrolling different from other pages? What's the benefit? Why bother?

untog 10y ago
IIRC the iOS UIScrollView has a different scroll behaviour when it's inside a UIWebView. So they might have reset that difference.
cramforce 10y ago
Everything scroll related is in CSS. The long explanation is here https://medium.com/@dvoytenko/amp-ios-scrolling-and-position-fixed-b854a5a0d451 https://medium.com/@dvoytenko/amp-ios-scrolling-and-position...
- Touche 10y ago
  I'm well aware of how janky position: fixed on mobile. The solution is not to use position: fixed, not to try to "fix" it and make the experience bad.