Add custom tooltips and scrolling to breadcrumbs

res/css/views/rooms/_RoomBreadcrumbs.scss

@@ -15,33 +15,29 @@ limitations under the License.
 */
 
 .mx_RoomBreadcrumbs {
-    overflow-x: auto;
     position: relative;
-    height: 32px;
+    height: 42px;
     margin: 8px;
     margin-bottom: 0;
-
-    overflow-x: hidden;
+    overflow-x: visible;
     display: flex;
     flex-direction: row;
 
-    > * {
-        margin-left: 4px;
+    .mx_AutoHideScrollbar_offset {
+        display: flex;
+        flex-direction: row;
+        height: 100%;
     }
 
-    &::after {
-        content: "";
-        position: absolute;
-        width: 15px;
-        top: 0;
-        right: 0;
-        height: 100%;
-        background: linear-gradient(to right, $panel-gradient);
+    .mx_RoomBreadcrumbs_crumb {
+        margin-left: 4px;
+        height: 32px;
+        display: inline-block;
+        transition: transform 0.3s, width 0.3s;
     }
 
     .mx_RoomBreadcrumbs_animate {
         margin-left: 0;
-        transition: transform 0.3s, width 0.3s;
         width: 32px;
         transform: scale(1);
     }
@@ -50,5 +46,34 @@ limitations under the License.
         width: 0;
         transform: scale(0);
     }
+
+
+    // Note: we have to manually control the gradient and stuff, but the IndicatorScrollbar
+    // will deal with left/right positioning for us. Normally we'd use position:sticky on
+    // a few key elements, however that doesn't work in horizontal scrolling scenarios.
+
+    .mx_IndicatorScrollbar_leftOverflowIndicator,
+    .mx_IndicatorScrollbar_rightOverflowIndicator {
+        display: none;
+    }
+
+    &.mx_IndicatorScrollbar_leftOverflow .mx_IndicatorScrollbar_leftOverflowIndicator,
+    &.mx_IndicatorScrollbar_rightOverflow .mx_IndicatorScrollbar_rightOverflowIndicator {
+        position: absolute;
+        top: 0;
+        bottom: 0;
+        width: 15px;
+        display: block;
+        pointer-events: none;
+        z-index: 100;
+    }
+
+    .mx_IndicatorScrollbar_leftOverflowIndicator {
+        background: linear-gradient(to left, $panel-gradient);
+    }
+
+    .mx_IndicatorScrollbar_rightOverflowIndicator {
+        background: linear-gradient(to right, $panel-gradient);
+    }
 }
 

src/components/structures/IndicatorScrollbar.js

@@ -15,16 +15,29 @@ limitations under the License.
 */
 
 import React from "react";
+import PropTypes from "prop-types";
 import AutoHideScrollbar from "./AutoHideScrollbar";
 
 export default class IndicatorScrollbar extends React.Component {
+    static PropTypes = {
+        // If true, the scrollbar will append mx_IndicatorScrollbar_leftOverflowIndicator
+        // and mx_IndicatorScrollbar_rightOverflowIndicator elements to the list for positioning
+        // by the parent element.
+        trackHorizontalOverflow: PropTypes.bool,
+    };
+
     constructor(props) {
         super(props);
         this._collectScroller = this._collectScroller.bind(this);
         this._collectScrollerComponent = this._collectScrollerComponent.bind(this);
         this.checkOverflow = this.checkOverflow.bind(this);
         this._scrollElement = null;
         this._autoHideScrollbar = null;
+
+        this.state = {
+            leftIndicatorOffset: 0,
+            rightIndicatorOffset: 0,
+        };
     }
 
     _collectScroller(scroller) {
@@ -43,6 +56,10 @@ export default class IndicatorScrollbar extends React.Component {
         const hasTopOverflow = this._scrollElement.scrollTop > 0;
         const hasBottomOverflow = this._scrollElement.scrollHeight >
             (this._scrollElement.scrollTop + this._scrollElement.clientHeight);
+        const hasLeftOverflow = this._scrollElement.scrollLeft > 0;
+        const hasRightOverflow = this._scrollElement.scrollWidth >
+            (this._scrollElement.scrollLeft + this._scrollElement.clientWidth);
+
         if (hasTopOverflow) {
             this._scrollElement.classList.add("mx_IndicatorScrollbar_topOverflow");
         } else {
@@ -53,10 +70,30 @@ export default class IndicatorScrollbar extends React.Component {
         } else {
             this._scrollElement.classList.remove("mx_IndicatorScrollbar_bottomOverflow");
         }
+        if (hasLeftOverflow) {
+            this._scrollElement.classList.add("mx_IndicatorScrollbar_leftOverflow");
+        } else {
+            this._scrollElement.classList.remove("mx_IndicatorScrollbar_leftOverflow");
+        }
+        if (hasRightOverflow) {
+            this._scrollElement.classList.add("mx_IndicatorScrollbar_rightOverflow");
+        } else {
+            this._scrollElement.classList.remove("mx_IndicatorScrollbar_rightOverflow");
+        }
 
         if (this._autoHideScrollbar) {
             this._autoHideScrollbar.checkOverflow();
         }
+
+        if (this.props.trackHorizontalOverflow) {
+            this.setState({
+                // Offset from absolute position of the container
+                leftIndicatorOffset: hasLeftOverflow ? `${this._scrollElement.scrollLeft}px` : '0',
+
+                // Negative because we're coming from the right
+                rightIndicatorOffset: hasRightOverflow ? `-${this._scrollElement.scrollLeft}px` : '0',
+            });
+        }
     }
 
     getScrollTop() {
@@ -70,12 +107,21 @@ export default class IndicatorScrollbar extends React.Component {
     }
 
     render() {
+        const leftIndicatorStyle = {left: this.state.leftIndicatorOffset};
+        const rightIndicatorStyle = {right: this.state.rightIndicatorOffset};
+        const leftOverflowIndicator = this.props.trackHorizontalOverflow
+            ? <div className="mx_IndicatorScrollbar_leftOverflowIndicator" style={leftIndicatorStyle} /> : null;
+        const rightOverflowIndicator = this.props.trackHorizontalOverflow
+            ? <div className="mx_IndicatorScrollbar_rightOverflowIndicator" style={rightIndicatorStyle} /> : null;
+
         return (<AutoHideScrollbar
             ref={this._collectScrollerComponent}
             wrappedRef={this._collectScroller}
             {... this.props}
         >
+            { leftOverflowIndicator }
             { this.props.children }
+            { rightOverflowIndicator }
         </AutoHideScrollbar>);
     }
 }

src/components/views/rooms/RoomBreadcrumbs.js

@@ -21,6 +21,7 @@ import MatrixClientPeg from "../../../MatrixClientPeg";
 import AccessibleButton from '../elements/AccessibleButton';
 import RoomAvatar from '../avatars/RoomAvatar';
 import classNames from 'classnames';
+import sdk from "../../../index";
 
 const MAX_ROOMS = 20;
 
@@ -83,7 +84,26 @@ export default class RoomBreadcrumbs extends React.Component {
         dis.dispatch({action: "view_room", room_id: room.roomId});
     }
 
+    _onMouseEnter(room) {
+        this._onHover(room);
+    }
+
+    _onMouseLeave(room) {
+        this._onHover(null); // clear hover states
+    }
+
+    _onHover(room) {
+        const rooms = this.state.rooms.slice();
+        for (const r of rooms) {
+            r.hover = room && r.room.roomId === room.roomId;
+        }
+        this.setState({rooms});
+    }
+
     render() {
+        const Tooltip = sdk.getComponent('elements.Tooltip');
+        const IndicatorScrollbar = sdk.getComponent('structures.IndicatorScrollbar');
+
         // check for collapsed here and
         // not at parent so we keep
         // rooms in our state
@@ -92,18 +112,31 @@ export default class RoomBreadcrumbs extends React.Component {
             return null;
         }
         const rooms = this.state.rooms;
-        const avatars = rooms.map(({room, animated}, i) => {
+        const avatars = rooms.map(({room, animated, hover}, i) => {
             const isFirst = i === 0;
             const classes = classNames({
+                "mx_RoomBreadcrumbs_crumb": true,
                 "mx_RoomBreadcrumbs_preAnimate": isFirst && !animated,
                 "mx_RoomBreadcrumbs_animate": isFirst,
             });
+
+            let tooltip = null;
+            if (hover) {
+                tooltip = <Tooltip label={room.name} />;
+            }
+
             return (
-                <AccessibleButton className={classes} key={room.roomId} title={room.name} onClick={() => this._viewRoom(room)}>
+                <AccessibleButton className={classes} key={room.roomId} onClick={() => this._viewRoom(room)}
+                    onMouseEnter={() => this._onMouseEnter(room)} onMouseLeave={() => this._onMouseLeave(room)}>
                     <RoomAvatar room={room} width={32} height={32} />
+                    {tooltip}
                 </AccessibleButton>
             );
         });
-        return (<div className="mx_RoomBreadcrumbs">{ avatars }</div>);
+        return (
+            <IndicatorScrollbar ref="scroller" className="mx_RoomBreadcrumbs" trackHorizontalOverflow={true}>
+                { avatars }
+            </IndicatorScrollbar>
+        );
     }
 }