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.
