Summary:
Incremental rendering is a tradeoff between throughput and responsiveness because it yields. When we have plenty of
buffer (say 50% of the target), we render incrementally to keep the app responsive. If we are dangerously low on buffer
(say below 25%) we always disable incremental to try to catch up as fast as possible. In between, we only disable
incremental while actively scrolling since it's unlikely the user will try to press a button while scrolling.
This also optimizes some things then incremental is switching back and forth.
I played around with making the render window itself adaptive, but it seems pretty futile to predict - once the user
decides to scroll quickly in some direction, it's pretty much too late and increasing the render window size won't help
because we're already limited by the render throughput at that point.
Reviewed By: ericvicenti
Differential Revision: D3250916
fbshipit-source-id: 930d418522a3bf3e20083e60f6eb6f891497a2b8
Summary:`WindowedListView` is designed for memory efficient scrolling of
huge/infinite lists of variable height rows. It works by measuring row heights
with `onLayout` and caching the results, then unmounting rows that scroll
offscreen, replacing them with an equivalent offset in the spacer view. Care is
taken to render a constant number of rows, and to only render one new row per
tick to improve framerate and app responsiveness. WLV is also compatible with
<Incremental> used within the rows themselves.
`WindowedListView` is not a drop-in replacement for `ListView` - it doesn't
support many of the features of `ListView`, such as section headers, only
accepts a simple array of data instead of a datasource, and doesn't support
horizontal scrolling. This may change in the future.
This is still experimental - we haven't deployed this for any production apps
yet.
Differential Revision: D2791402
fb-gh-sync-id: 5f104e0903f6ba586d2d651bdf82863a231279d8
fbshipit-source-id: 5f104e0903f6ba586d2d651bdf82863a231279d8
Summary:Everything wrapped in `<Incremental>` is rendered sequentially via `InteractionManager`.
The `onDone` callback is called when all descendent incremental components have
finished rendering, used by `<IncrementalPresenter>` to make the story visible all at once
instead of the parts popping in randomly.
This includes an example that demonstrates streaming rendering and the use of
`<IncrementalPresenter>`. Pressing down pauses rendering and you can see the
`TouchableOpacity` animation runs smoothly. Video:
https://youtu.be/4UNf4-8orQ4
Ideally this will be baked into React Core at some point, but according to jordwalke that's
going to require a major refactoring and take a long time, so going with this for now.
Reviewed By: ericvicenti
Differential Revision: D2506522
fb-gh-sync-id: 5969bf248de10d38b0ac22f34d7d49bf1b3ac4b6
shipit-source-id: 5969bf248de10d38b0ac22f34d7d49bf1b3ac4b6
Spencer Ahrens
glevi@fb.com