Making sure that a node is intersected by the bottom of the wrapper is a bit overkill, given that we iterate from the bottom. This also prevents the scenario of having no nodes that are not precisely intersected, but possibly straddling the bottom of the wrapper.
The actual fix to https://github.com/vector-im/riot-web/issues/3175 is this change to `_saveScrollState`, which is to pick the trackedScrollToken based on which node is intersected by the bottom of the scroll panel. This is opposed to the previous logic that picked based on which node was the first from the bottom to be above the bottom of the viewport.
In the case where the viewport bottom does not intersect any events, the topmost event is used.
It seems that a number of the tests had started failing when run in
Chrome. They were fine under PhantomJS, but the MegolmExport tests only work
under Chrome, and I need them to work...
Mostly the problems were timing-related, where assumptions made about how
quickly the `then` handler on a promise would be called were no longer
valid. Possibly Chrome 55 has made some changes to the relative priorities of
setTimeout and sendMessage calls.
One of the TimelinePanel tests was failing because it was expecting the contents
of a div to take up more room than they actually were. It's possible this is
something very environment-specific; hopefully the new value will work on a
wider range of machines.
Also some logging tweaks.
This increases `UNPAGINATION_PADDING` (see the ASCII on ScrollPanel.js, `_getExcessHeight`), and also debounces unfilling requests made for 200ms. This forces unfilling requests not to be sent unless the next 200ms has no scrolling, effectively.
Instead of using a window of a fixed number of events, unpaginate based on the distance of the viewport from the end of the scroll range.
The ScrollPanel uses the scrollTokens to convey to its parent (the TimelinePanel, in this case) the point to unpaginate up to. The TimelinePanel then takes a chunk of events off the front or back of `this.state.events` using `timelineWindow.unpaginate`.
Fixes https://github.com/vector-im/vector-web/issues/2020
Controls whether a scrollPanel starts off at the bottom.
This may not be necessary and could either be derived from stickyBottom, but
this means I can be sure that the behaviour of ScrollPanel is completely
unchanged for all other uses to avoid breaking any other uses of
ScrollPanel.
Under certain conditions, it was possible to get stuck in a state where any
user-initiated scroll would be met with "Working around
vector-im/vector-web#528" and overridden. Fix this by removing the duplication
between _lastSetScroll and recentEventScroll, and using _lastSetScroll which is
more reliable.
The most recent problem was that we were setting _lastSetScroll whenever we
wrote to scrollTop (and ignoring the next scroll event which matched that
offset), but if there was no change to scrollTop, we wouldn't actually get a
scroll event, so would ignore some future scroll event instead.
Make sure that we only set _lastSetScroll if there's a change to scrollTop.
(Fixes https://github.com/vector-im/vector-web/issues/1162, more)
When the user scrolls up, and scrolls back to where they were, we want to save
the final scroll state. We were ignoring it because it looked the same as the
last autoscroll.
Fixes https://github.com/vector-im/vector-web/issues/1162
We need two modes of operation for ScrollPanel.scrollToToken:
For jump-to-read-marker, we want it 1/3 of the way down the screen.
For search clickthrough, and hyperlinked events, we want put the event in the
*middle* of the screen.
Fixes https://github.com/vector-im/vector-web/issues/1032
This adds support for links to particular event ids: add /<eventId> to the URL
for a room.
This commit also ensures that we scroll to the 'read marker' when switching to
a room which has no previous scroll state, as well as preventing that marker
from going past the middle of the screen.
This also reinstates the preservation of scroll state when switching rooms,
which was disabled previously.
Given we want to use isAtBottom to figure out whether to show 'unread messages'
counts, we ought to return the current scroll state, rather than the saved one.
This fixesvector-im/vector-web#576
The dance to avoid doing repeated fill requests on every update is common, so
add it to ScrollPanel. Let onFillRequest return a promise, which prevents any
updates until it completes.
