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use transparent scrollbars on not hover to emulate scrolbar on hover

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allows us to get rid of the margin-right hack as well
This commit is contained in:
Bruno Windels 2020-03-25 19:24:32 +01:00
parent 44ce5b5764
commit 0436507574
2 changed files with 21 additions and 114 deletions
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78
res/css/structures/_AutoHideScrollbar.scss
View file

@ -14,76 +14,34 @@ See the License for the specific language governing permissions and
limitations under the License.
*/
/* This file has CSS for both native and non-native scrollbars in an order
* that's fairly logical to read but duplicates a selector to separate the
* hiding/showing from the sizing.
*/
/* stylelint-disable no-duplicate-selectors */
/*
1. for browsers that support native overlay auto-hiding scrollbars
*/
.mx_AutoHideScrollbar {
overflow-x: hidden;
overflow-y: auto;
overflow-y: overlay; // where supported
-ms-overflow-style: -ms-autohiding-scrollbar;
}
/*
2. webkit also supports overflow:overlay where the scrollbars don't take any space
in the layout but they don't autohide, so do that only on hover
*/
body.mx_scrollbar_overlay_noautohide .mx_AutoHideScrollbar {
overflow-y: hidden;
}
body.mx_scrollbar_overlay_noautohide .mx_AutoHideScrollbar:hover {
overflow-y: overlay;
}
/*
3. as a last fallback, compensate for the scrollbar taking up space in the layout
by having giving the child element (.mx_AutoHideScrollbar_offset) a
negative right margin of the width of the scrollbar when the container
is overflowing. This is what Firefox ends up using. Overflow is detected
in javascript, and adds the mx_AutoHideScrollbar_overflow class to the container.
This only works in Firefox, which should be fine as this fallback is only needed there.
*/
body.mx_scrollbar_nooverlay {
.mx_AutoHideScrollbar {
overflow-y: hidden;
&::-webkit-scrollbar {
width: 6px;
height: 6px;
background-color: transparent;
}
.mx_AutoHideScrollbar:hover {
overflow-y: auto;
&::-webkit-scrollbar-thumb {
border-radius: 3px;
background-color: transparent;
}
/*
offset scrollbar width with negative margin-right
include before and after psuedo-elements here so they can
be used to do something interesting like scroll-indicating
gradients (see IndicatorScrollBar)
*/
.mx_AutoHideScrollbar:hover.mx_AutoHideScrollbar_overflow > .mx_AutoHideScrollbar_offset,
.mx_AutoHideScrollbar:hover.mx_AutoHideScrollbar_overflow::before,
.mx_AutoHideScrollbar:hover.mx_AutoHideScrollbar_overflow::after {
margin-right: calc(-1 * var(--scrollbar-width));
}
}
// style the native scrollbars ...
// ... standard css scrollbars (firefox at time of writing)
.mx_AutoHideScrollbar {
scrollbar-color: $scrollbar-thumb-color $scrollbar-track-color;
scrollbar-color: transparent transparent;
scrollbar-width: thin;
}
// or fallback for webkit browsers
::-webkit-scrollbar {
width: 6px;
height: 6px;
background-color: $scrollbar-track-color;
}
::-webkit-scrollbar-thumb {
background-color: $scrollbar-thumb-color;
border-radius: 3px;
.mx_AutoHideScrollbar:hover {
&::-webkit-scrollbar {
background-color: $scrollbar-track-color;
}
&::-webkit-scrollbar-thumb {
background-color: $scrollbar-thumb-color;
}
scrollbar-color: $scrollbar-thumb-color $scrollbar-track-color;
}

57
src/components/structures/AutoHideScrollbar.js
View file

@ -18,7 +18,7 @@ import React from "react";
// derived from code from github.com/noeldelgado/gemini-scrollbar
// Copyright (c) Noel Delgado <pixelia.me@gmail.com> (pixelia.me)
function getScrollbarWidth(alternativeOverflow) {
function getScrollbarWidth() {
const div = document.createElement('div');
div.className = 'mx_AutoHideScrollbar'; //to get width of css scrollbar
div.style.position = 'absolute';
@ -26,9 +26,6 @@ function getScrollbarWidth(alternativeOverflow) {
div.style.width = '100px';
div.style.height = '100px';
div.style.overflow = "scroll";
if (alternativeOverflow) {
div.style.overflow = alternativeOverflow;
}
div.style.msOverflowStyle = '-ms-autohiding-scrollbar';
document.body.appendChild(div);
const scrollbarWidth = (div.offsetWidth - div.clientWidth);
@ -39,18 +36,7 @@ function getScrollbarWidth(alternativeOverflow) {
function install() {
const scrollbarWidth = getScrollbarWidth();
if (scrollbarWidth !== 0) {
const hasForcedOverlayScrollbar = getScrollbarWidth('overlay') === 0;
// overflow: overlay on webkit doesn't auto hide the scrollbar
if (hasForcedOverlayScrollbar) {
document.body.classList.add("mx_scrollbar_overlay_noautohide");
} else {
document.body.classList.add("mx_scrollbar_nooverlay");
const style = document.createElement('style');
style.type = 'text/css';
style.innerText =
`body.mx_scrollbar_nooverlay { --scrollbar-width: ${scrollbarWidth}px; }`;
document.head.appendChild(style);
}
document.body.classList.add("mx_scrollbar_noautohide");
}
}
@ -67,42 +53,7 @@ const installBodyClassesIfNeeded = (function() {
export default class AutoHideScrollbar extends React.Component {
constructor(props) {
super(props);
this.onOverflow = this.onOverflow.bind(this);
this.onUnderflow = this.onUnderflow.bind(this);
this._collectContainerRef = this._collectContainerRef.bind(this);
this._needsOverflowListener = null;
}
onOverflow() {
this.containerRef.classList.add("mx_AutoHideScrollbar_overflow");
this.containerRef.classList.remove("mx_AutoHideScrollbar_underflow");
}
onUnderflow() {
this.containerRef.classList.remove("mx_AutoHideScrollbar_overflow");
this.containerRef.classList.add("mx_AutoHideScrollbar_underflow");
}
checkOverflow() {
if (!this._needsOverflowListener) {
return;
}
if (this.containerRef.scrollHeight > this.containerRef.clientHeight) {
this.onOverflow();
} else {
this.onUnderflow();
}
}
componentDidUpdate() {
this.checkOverflow();
}
componentDidMount() {
installBodyClassesIfNeeded();
this._needsOverflowListener =
document.body.classList.contains("mx_scrollbar_nooverlay");
this.checkOverflow();
}
_collectContainerRef(ref) {
@ -126,9 +77,7 @@ export default class AutoHideScrollbar extends React.Component {
onScroll={this.props.onScroll}
onWheel={this.props.onWheel}
>
<div className="mx_AutoHideScrollbar_offset">
{ this.props.children }
</div>
{ this.props.children }
</div>);
}
}