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Merge pull request #4166 from matrix-org/bwindels/relativescrolling 

Adjust scroll offset with relative scrolling
pull/21833/head
Bruno Windels 2020-03-03 15:07:42 +00:00 committed by GitHub
parent b23eaa1ce7 3e39cebb8f
commit 72af620d92
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 8 additions and 9 deletions
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17
src/components/structures/ScrollPanel.js
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@ -523,7 +523,7 @@ export default createReactClass({
scrollRelative: function(mult) { scrollRelative: function(mult) {
const scrollNode = this._getScrollNode(); const scrollNode = this._getScrollNode();
const delta = mult * scrollNode.clientHeight * 0.5; const delta = mult * scrollNode.clientHeight * 0.5;
scrollNode.scrollTop = scrollNode.scrollTop + delta; scrollNode.scrollBy(0, delta);
this._saveScrollState(); this._saveScrollState();
}, },
@ -705,17 +705,15 @@ export default createReactClass({
// the currently filled piece of the timeline // the currently filled piece of the timeline
if (trackedNode) { if (trackedNode) {
const oldTop = trackedNode.offsetTop; const oldTop = trackedNode.offsetTop;
// changing the height might change the scrollTop
// if the new height is smaller than the scrollTop.
// We calculate the diff that needs to be applied
// ourselves, so be sure to measure the
// scrollTop before changing the height.
const preexistingScrollTop = sn.scrollTop;
itemlist.style.height = `${newHeight}px`; itemlist.style.height = `${newHeight}px`;
const newTop = trackedNode.offsetTop; const newTop = trackedNode.offsetTop;
const topDiff = newTop - oldTop; const topDiff = newTop - oldTop;
sn.scrollTop = preexistingScrollTop + topDiff; // important to scroll by a relative amount as
debuglog("updateHeight to", {newHeight, topDiff, preexistingScrollTop}); // reading scrollTop and then setting it might
// yield out of date values and cause a jump
// when setting it
sn.scrollBy(0, topDiff);
debuglog("updateHeight to", {newHeight, topDiff});
} }
} }
}, },
@ -767,6 +765,7 @@ export default createReactClass({
}, },
_topFromBottom(node) { _topFromBottom(node) {
// current capped height - distance from top = distance from bottom of container to top of tracked element
return this._itemlist.current.clientHeight - node.offsetTop; return this._itemlist.current.clientHeight - node.offsetTop;
}, },