Merge pull request #43 from brown-dash/temporalmedia-mehek

Temporalmedia mehek - audio and video UI updates. adds trimming, zooming, and volume controls. replaces native video controls with dash UI

1 files changed, 405 insertions, 284 deletions

diff --git a/src/client/views/collections/CollectionStackedTimeline.tsx b/src/client/views/collections/CollectionStackedTimeline.tsx
index 74bfc3a88..bd7d0083b 100644
--- a/src/client/views/collections/CollectionStackedTimeline.tsx
+++ b/src/client/views/collections/CollectionStackedTimeline.tsx
@@ -4,8 +4,7 @@ import {
     computed,
     IReactionDisposer,
     observable,
-    reaction,
-    runInAction,
+    reaction
 } from "mobx";
 import { observer } from "mobx-react";
 import { computedFn } from "mobx-utils";
@@ -20,37 +19,46 @@ import {
     formatTime,
     OmitKeys,
     returnFalse,
-    returnOne,
-    setupMoveUpEvents,
-    StopEvent,
-    returnTrue,
+    returnOne, returnTrue, setupMoveUpEvents, smoothScrollHorizontal, StopEvent
 } from "../../../Utils";
 import { Docs } from "../../documents/Documents";
+import { DocumentManager } from "../../util/DocumentManager";
+import { DragManager } from "../../util/DragManager";
 import { LinkManager } from "../../util/LinkManager";
 import { Scripting } from "../../util/Scripting";
 import { SelectionManager } from "../../util/SelectionManager";
+import { SnappingManager } from "../../util/SnappingManager";
 import { Transform } from "../../util/Transform";
-import { undoBatch } from "../../util/UndoManager";
+import { undoBatch, UndoManager } from "../../util/UndoManager";
 import { AudioWaveform } from "../AudioWaveform";
 import { CollectionSubView } from "../collections/CollectionSubView";
+import { Colors } from "../global/globalEnums";
 import { LightboxView } from "../LightboxView";
 import {
     DocAfterFocusFunc,
     DocFocusFunc,
     DocumentView,
-    DocumentViewProps,
+    DocumentViewProps
 } from "../nodes/DocumentView";
 import { LabelBox } from "../nodes/LabelBox";
 import "./CollectionStackedTimeline.scss";
-import { Colors } from "../global/globalEnums";
-import { DocumentManager } from "../../util/DocumentManager";
-import { SnappingManager } from "../../util/SnappingManager";
-import { DragManager } from "../../util/DragManager";
+
+
+
+/**
+ * CollectionStackedTimeline
+ * Main component: CollectionStackedTimeline.tsx
+ * Supporting Components: AudioWaveform
+ * 
+ * CollectionStackedTimeline is a collection view used for audio and video nodes to display a timeline of the temporal media documents with an audio waveform and markers for links and annotations
+ * The actual media is handled in the containing classes (AudioBox, VideoBox) but the timeline deals with rendering and updating timecodes, links, and trimming.
+ * When trimming there are two pairs of times that are tracked: trimStart and trimEnd are the bounds of the trim controls, clipStart and clipEnd are the actual trimmed playback bounds of the clip
+ */
+
 
 type PanZoomDocument = makeInterface<[]>;
 const PanZoomDocument = makeInterface();
 export type CollectionStackedTimelineProps = {
-    duration: number;
     Play: () => void;
     Pause: () => void;
     playLink: (linkDoc: Doc) => void;
@@ -61,64 +69,58 @@ export type CollectionStackedTimelineProps = {
     endTag: string;
     mediaPath: string;
     dictationKey: string;
-    trimming: boolean;
-    trimStart: number;
-    trimEnd: number;
-    trimDuration: number;
-    setStartTrim: (newStart: number) => void;
-    setEndTrim: (newEnd: number) => void;
+    rawDuration: number;
+    fieldKey: string;
 };
 
+// trimming state: shows full clip, current trim bounds, or not trimming
+export enum TrimScope {
+    All = 2,
+    Clip = 1,
+    None = 0,
+}
+
+
 @observer
 export class CollectionStackedTimeline extends CollectionSubView<
     PanZoomDocument,
     CollectionStackedTimelineProps
 >(PanZoomDocument) {
-    @observable static SelectingRegion: CollectionStackedTimeline | undefined =
-        undefined;
+    @observable static SelectingRegion: CollectionStackedTimeline | undefined; // timeline selection region
+    @observable public static CurrentlyPlaying: Doc[]; // tracks all currently playing audio and video docs
+
     static RangeScript: ScriptField;
     static LabelScript: ScriptField;
     static RangePlayScript: ScriptField;
     static LabelPlayScript: ScriptField;
 
-    private _timeline: HTMLDivElement | null = null;
+    private _timeline: HTMLDivElement | null = null; // ref to actual timeline div
+    private _timelineWrapper: HTMLDivElement | null = null; // ref to timeline wrapper div for zooming and scrolling
     private _markerStart: number = 0;
-    @observable _markerEnd: number = 0;
+    @observable _markerEnd: number | undefined;
+    @observable _trimming: number = TrimScope.None;
+    @observable _trimStart: number = 0; // trim controls start pos
+    @observable _trimEnd: number = 0; // trim controls end pos
 
-    get minLength() {
-        const rect = this._timeline?.getBoundingClientRect();
-        if (rect) {
-            return 0.05 * this.duration;
-        }
-        return 0;
-    }
+    @observable _zoomFactor: number = 1;
 
-    get trimStart() {
-        return this.props.trimStart;
-    }
+    @observable _scroll: number = 0;
 
-    get trimEnd() {
-        return this.props.trimEnd;
-    }
+    // ensures that clip doesn't get trimmed so small that controls cannot be adjusted anymore 
+    get minTrimLength() { return Math.max(this._timeline?.getBoundingClientRect() ? 0.05 * this.clipDuration : 0, 0.5) }
 
-    get duration() {
-        return this.props.duration;
-    }
+    @computed get trimStart() { return this.IsTrimming !== TrimScope.None ? this._trimStart : this.clipStart; }
+    @computed get trimDuration() { return this.trimEnd - this.trimStart; }
+    @computed get trimEnd() { return this.IsTrimming !== TrimScope.None ? this._trimEnd : this.clipEnd; }
+
+    @computed get clipStart() { return this.IsTrimming === TrimScope.All ? 0 : NumCast(this.layoutDoc.clipStart); }
+    @computed get clipDuration() { return this.clipEnd - this.clipStart; }
+    @computed get clipEnd() { return this.IsTrimming === TrimScope.All ? this.props.rawDuration : NumCast(this.layoutDoc.clipEnd, this.props.rawDuration); }
+
+    @computed get currentTime() { return NumCast(this.layoutDoc._currentTimecode); }
+
+    @computed get zoomFactor() { return this._zoomFactor }
 
-    @computed get currentTime() {
-        return NumCast(this.layoutDoc._currentTimecode);
-    }
-    @computed get selectionContainer() {
-        return CollectionStackedTimeline.SelectingRegion !== this ? null : (
-            <div
-                className="collectionStackedTimeline-selector"
-                style={{
-                    left: `${((Math.min(this._markerStart, this._markerEnd) - this.trimStart) / this.props.trimDuration) * 100}%`,
-                    width: `${(Math.abs(this._markerStart - this._markerEnd) / this.props.trimDuration) * 100}%`,
-                }}
-            />
-        );
-    }
 
     constructor(props: any) {
         super(props);
@@ -142,60 +144,100 @@ export class CollectionStackedTimeline extends CollectionSubView<
     componentDidMount() {
         document.addEventListener("keydown", this.keyEvents, true);
     }
+
+    @action
     componentWillUnmount() {
         document.removeEventListener("keydown", this.keyEvents, true);
         if (CollectionStackedTimeline.SelectingRegion === this) {
-            runInAction(
-                () => (CollectionStackedTimeline.SelectingRegion = undefined)
-            );
+            CollectionStackedTimeline.SelectingRegion = undefined;
         }
     }
 
-    anchorStart = (anchor: Doc) =>
-        NumCast(anchor._timecodeToShow, NumCast(anchor[this.props.startTag]))
-    anchorEnd = (anchor: Doc, val: any = null) => {
-        const endVal = NumCast(anchor[this.props.endTag], val);
-        return NumCast(
-            anchor._timecodeToHide,
-            endVal === undefined ? null : endVal
-        );
+
+    public get IsTrimming() { return this._trimming; }
+
+    @action
+    public StartTrimming(scope: TrimScope) {
+        this._trimStart = this.clipStart;
+        this._trimEnd = this.clipEnd;
+        this._trimming = scope;
+    }
+    @action
+    public StopTrimming() {
+        this.layoutDoc.clipStart = this.trimStart;
+        this.layoutDoc.clipEnd = this.trimEnd;
+        this._trimming = TrimScope.None;
     }
+
+    @action
+    public setZoom(zoom: number) {
+        this._zoomFactor = zoom;
+    }
+
+
+    anchorStart = (anchor: Doc) => NumCast(anchor._timecodeToShow, NumCast(anchor[this.props.startTag]));
+    anchorEnd = (anchor: Doc, val: any = null) => NumCast(anchor._timecodeToHide, NumCast(anchor[this.props.endTag], val) ?? null);
+
+
+    // converts screen pixel offset to time
     toTimeline = (screen_delta: number, width: number) => {
         return Math.max(
-            this.trimStart,
-            Math.min(this.trimEnd, (screen_delta / width) * this.props.trimDuration + this.trimStart));
+            this.clipStart,
+            Math.min(this.clipEnd, (screen_delta / width) * this.clipDuration + this.clipStart));
     }
 
+
     rangeClickScript = () => CollectionStackedTimeline.RangeScript;
     rangePlayScript = () => CollectionStackedTimeline.RangePlayScript;
 
-    // for creating key anchors with key events
+
+    // handles key events for for creating key anchors, scrubbing, exiting trim
     @action
     keyEvents = (e: KeyboardEvent) => {
         if (
             !(e.target instanceof HTMLInputElement) &&
             this.props.isSelected(true)
         ) {
+            // if shift pressed scrub 1 second otherwise 1/10th
+            const jump = e.shiftKey ? 1 : 0.1;
+            e.stopPropagation();
             switch (e.key) {
                 case " ":
                     if (!CollectionStackedTimeline.SelectingRegion) {
                         this._markerStart = this._markerEnd = this.currentTime;
                         CollectionStackedTimeline.SelectingRegion = this;
                     } else {
+                        this._markerEnd = this.currentTime;
                         CollectionStackedTimeline.createAnchor(
                             this.rootDoc,
                             this.dataDoc,
                             this.props.fieldKey,
                             this.props.startTag,
                             this.props.endTag,
-                            this.currentTime
+                            this._markerStart,
+                            this._markerEnd
                         );
+                        this._markerEnd = undefined;
                         CollectionStackedTimeline.SelectingRegion = undefined;
                     }
+                    break;
+                case "Escape":
+                    // abandons current trim
+                    this._trimStart = this.clipStart;
+                    this._trimStart = this.clipEnd;
+                    this._trimming = TrimScope.None;
+                    break;
+                case "ArrowLeft":
+                    this.props.setTime(Math.min(Math.max(this.clipStart, this.currentTime - jump), this.clipEnd));
+                    break;
+                case "ArrowRight":
+                    this.props.setTime(Math.min(Math.max(this.clipStart, this.currentTime + jump), this.clipEnd));
+                    break;
             }
         }
     }
 
+
     getLinkData(l: Doc) {
         let la1 = l.anchor1 as Doc;
         let la2 = l.anchor2 as Doc;
@@ -210,28 +252,25 @@ export class CollectionStackedTimeline extends CollectionSubView<
         return { la1, la2, linkTime };
     }
 
-    // starting the drag event for anchor resizing
+
+    // handles dragging selection to create markers
     @action
     onPointerDownTimeline = (e: React.PointerEvent): void => {
         const rect = this._timeline?.getBoundingClientRect();
         const clientX = e.clientX;
+        const diff = rect ? clientX - rect?.x : null;
+        const shiftKey = e.shiftKey;
         if (rect && this.props.isContentActive()) {
             const wasPlaying = this.props.playing();
             if (wasPlaying) this.props.Pause();
-            const wasSelecting = CollectionStackedTimeline.SelectingRegion === this;
+            var wasSelecting = this._markerEnd !== undefined;
             setupMoveUpEvents(
                 this,
                 e,
                 action((e) => {
-                    if (
-                        !wasSelecting &&
-                        CollectionStackedTimeline.SelectingRegion !== this
-                    ) {
-                        this._markerStart = this._markerEnd = this.toTimeline(
-                            clientX - rect.x,
-                            rect.width
-                        );
-                        CollectionStackedTimeline.SelectingRegion = this;
+                    if (!wasSelecting) {
+                        this._markerStart = this._markerEnd = this.toTimeline(clientX - rect.x, rect.width);
+                        wasSelecting = true;
                     }
                     this._markerEnd = this.toTimeline(e.clientX - rect.x, rect.width);
                     return false;
@@ -245,9 +284,8 @@ export class CollectionStackedTimeline extends CollectionSubView<
                     }
                     if (
                         !isClick &&
-                        CollectionStackedTimeline.SelectingRegion === this &&
                         Math.abs(movement[0]) > 15 &&
-                        !this.props.trimming
+                        !this.IsTrimming
                     ) {
                         const anchor = CollectionStackedTimeline.createAnchor(
                             this.rootDoc,
@@ -261,11 +299,18 @@ export class CollectionStackedTimeline extends CollectionSubView<
                         setTimeout(() => DocumentManager.Instance.getDocumentView(anchor)?.select(false));
                     }
                     (!isClick || !wasSelecting) &&
-                        (CollectionStackedTimeline.SelectingRegion = undefined);
+                        (this._markerEnd = undefined);
                 }),
                 (e, doubleTap) => {
-                    this.props.select(false);
-                    e.shiftKey &&
+                    if (e.button !== 2) {
+                        this.props.select(false);
+                        !wasPlaying && doubleTap && this.props.Play();
+                    }
+                },
+                this.props.isSelected(true) || this.props.isContentActive(),
+                undefined,
+                () => {
+                    if (shiftKey) {
                         CollectionStackedTimeline.createAnchor(
                             this.rootDoc,
                             this.dataDoc,
@@ -274,23 +319,17 @@ export class CollectionStackedTimeline extends CollectionSubView<
                             this.props.endTag,
                             this.currentTime
                         );
-                    !wasPlaying && doubleTap && this.props.Play();
-                },
-                this.props.isSelected(true) || this.props.isContentActive(),
-                undefined,
-                () => {
-                    !wasPlaying &&
-                        (this.props.trimming && this.duration ?
-                            this.props.setTime(((clientX - rect.x) / rect.width) * this.duration)
-                            :
-                            this.props.setTime(((clientX - rect.x) / rect.width) * this.props.trimDuration + this.trimStart)
-                        );
+                    } else {
+                        !wasPlaying && this.props.setTime(this.toTimeline(clientX - rect.x, rect.width));
+                    }
                 }
             );
         }
 
     }
 
+
+    // for dragging trim start handle
     @action
     trimLeft = (e: React.PointerEvent): void => {
         const rect = this._timeline?.getBoundingClientRect();
@@ -300,25 +339,24 @@ export class CollectionStackedTimeline extends CollectionSubView<
             e,
             action((e, [], []) => {
                 if (rect && this.props.isContentActive()) {
-                    this.props.setStartTrim(Math.min(
+                    this._trimStart = Math.min(
                         Math.max(
-                            this.trimStart + (e.movementX / rect.width) * this.duration,
-                            0
+                            this.trimStart + (e.movementX / rect.width) * this.clipDuration,
+                            this.clipStart
                         ),
-                        this.trimEnd - this.minLength
-                    ));
+                        this.trimEnd - this.minTrimLength
+                    );
                 }
                 return false;
             }),
             emptyFunction,
             action((e, doubleTap) => {
-                if (doubleTap) {
-                    this.props.setStartTrim(0);
-                }
+                doubleTap && (this._trimStart = this.clipStart);
             })
         );
     }
 
+    // for dragging trim end handle
     @action
     trimRight = (e: React.PointerEvent): void => {
         const rect = this._timeline?.getBoundingClientRect();
@@ -328,32 +366,64 @@ export class CollectionStackedTimeline extends CollectionSubView<
             e,
             action((e, [], []) => {
                 if (rect && this.props.isContentActive()) {
-                    this.props.setEndTrim(Math.max(
+                    this._trimEnd = Math.max(
                         Math.min(
-                            this.trimEnd + (e.movementX / rect.width) * this.duration,
-                            this.duration
+                            this.trimEnd + (e.movementX / rect.width) * this.clipDuration,
+                            this.clipEnd
                         ),
-                        this.trimStart + this.minLength
-                    ));
+                        this.trimStart + this.minTrimLength
+                    );
                 }
                 return false;
             }),
             emptyFunction,
             action((e, doubleTap) => {
-                if (doubleTap) {
-                    this.props.setEndTrim(this.duration);
-                }
+                doubleTap && (this._trimEnd = this.clipEnd);
             })
         );
     }
 
+
+    // for rendering scrolling when timeline zoomed
+    @action
+    setScroll = (e: React.UIEvent) => {
+        e.stopPropagation();
+        this._scroll = this._timelineWrapper!.scrollLeft;
+    }
+
+    // smooth scrolls to time like when following links overflowed due to zoom
+    @action
+    scrollToTime = (time: number) => {
+        if (this._timelineWrapper) {
+            if (time > this.toTimeline(this._scroll + this.props.PanelWidth(), this.timelineContentWidth)) {
+                this._scroll = Math.min(this._scroll + this.props.PanelWidth(), this.timelineContentWidth - this.props.PanelWidth());
+                smoothScrollHorizontal(200, this._timelineWrapper, this._scroll);
+            }
+            else if (time < this.toTimeline(this._scroll, this.timelineContentWidth)) {
+                this._scroll = time / this.timelineContentWidth * this.clipDuration;
+                smoothScrollHorizontal(200, this._timelineWrapper, this._scroll);
+            }
+        }
+    }
+
+
+    // handles dragging and dropping markers in timeline
     @action
     internalDocDrop(e: Event, de: DragManager.DropEvent, docDragData: DragManager.DocumentDragData, xp: number) {
         if (!de.embedKey && this.props.layerProvider?.(this.props.Document) !== false && this.props.Document._isGroup) return false;
         if (!super.onInternalDrop(e, de)) return false;
 
-
         // determine x coordinate of drop and assign it to the documents being dragged  --- see internalDocDrop of collectionFreeFormView.tsx for how it's done when dropping onto a 2D freeform view
+        const localPt = this.props.ScreenToLocalTransform().transformPoint(de.x, de.y);
+        const x = localPt[0] - docDragData.offset[0];
+        const timelinePt = this.toTimeline(x + this._scroll, this.timelineContentWidth);
+        docDragData.droppedDocuments.forEach(drop => {
+            const anchorEnd = this.anchorEnd(drop);
+            if (anchorEnd !== undefined) {
+                Doc.SetInPlace(drop, drop._timecodeToHide === undefined ? this.props.endTag : "timecodeToHide", timelinePt + anchorEnd - this.anchorStart(drop), false);
+            }
+            Doc.SetInPlace(drop, drop._timecodeToShow === undefined ? this.props.startTag : "timecodeToShow", timelinePt, false);
+        });
 
         return true;
     }
@@ -363,6 +433,8 @@ export class CollectionStackedTimeline extends CollectionSubView<
         return false;
     }
 
+
+    // creates marker on timeline
     @undoBatch
     @action
     static createAnchor(
@@ -385,10 +457,11 @@ export class CollectionStackedTimeline extends CollectionSubView<
             hideLinkButton: true,
             annotationOn: rootDoc,
             _timelineLabel: true,
+            borderRounding: anchorEndTime === undefined ? "100%" : undefined
         });
         Doc.GetProto(anchor)[startTag] = anchorStartTime;
         Doc.GetProto(anchor)[endTag] = anchorEndTime;
-        if (Cast(dataDoc[fieldKey], listSpec(Doc), null) !== undefined) {
+        if (Cast(dataDoc[fieldKey], listSpec(Doc), null)) {
             Cast(dataDoc[fieldKey], listSpec(Doc), []).push(anchor);
         } else {
             dataDoc[fieldKey] = new List<Doc>([anchor]);
@@ -396,13 +469,17 @@ export class CollectionStackedTimeline extends CollectionSubView<
         return anchor;
     }
 
+
     @action
     playOnClick = (anchorDoc: Doc, clientX: number) => {
         const seekTimeInSeconds = this.anchorStart(anchorDoc) - 0.25;
         const endTime = this.anchorEnd(anchorDoc);
         if (this.layoutDoc.autoPlayAnchors) {
             if (this.props.playing()) this.props.Pause();
-            else this.props.playFrom(seekTimeInSeconds, endTime);
+            else {
+                this.props.playFrom(seekTimeInSeconds, endTime);
+                this.scrollToTime(seekTimeInSeconds);
+            }
         } else {
             if (
                 seekTimeInSeconds < NumCast(this.layoutDoc._currentTimecode) &&
@@ -415,6 +492,7 @@ export class CollectionStackedTimeline extends CollectionSubView<
                 }
             } else {
                 this.props.playFrom(seekTimeInSeconds, endTime);
+                this.scrollToTime(seekTimeInSeconds);
             }
         }
         return { select: true };
@@ -454,11 +532,11 @@ export class CollectionStackedTimeline extends CollectionSubView<
         m: Doc,
         placed: { anchorStartTime: number; anchorEndTime: number; level: number }[]
     ) => {
-        const timelineContentWidth = this.props.PanelWidth();
+        const timelineContentWidth = this.timelineContentWidth;
         const x1 = this.anchorStart(m);
         const x2 = this.anchorEnd(
             m,
-            x1 + (10 / timelineContentWidth) * this.duration
+            x1 + (10 / timelineContentWidth) * this.clipDuration
         );
         let max = 0;
         const overlappedLevels = new Set(
@@ -483,15 +561,20 @@ export class CollectionStackedTimeline extends CollectionSubView<
         return level;
     }
 
+
     dictationHeightPercent = 50;
-    dictationHeight = () =>
-        (this.props.PanelHeight() * (100 - this.dictationHeightPercent)) / 100
-    timelineContentHeight = () =>
-        (this.props.PanelHeight() * this.dictationHeightPercent) / 100
-    dictationScreenToLocalTransform = () =>
-        this.props
-            .ScreenToLocalTransform()
-            .translate(0, -this.timelineContentHeight())
+    dictationHeight = () => (this.props.PanelHeight() * (100 - this.dictationHeightPercent)) / 100;
+
+    @computed get timelineContentHeight() { return this.props.PanelHeight() * this.dictationHeightPercent / 100; }
+    @computed get timelineContentWidth() { return this.props.PanelWidth() * this.zoomFactor - 4 };  // subtract size of container border
+
+    dictationScreenToLocalTransform = () => this.props.ScreenToLocalTransform().translate(0, -this.timelineContentHeight);
+
+    isContentActive = () => this.props.isSelected() || this.props.isContentActive();
+
+    currentTimecode = () => this.currentTime;
+
+
     @computed get renderDictation() {
         const dictation = Cast(this.dataDoc[this.props.dictationKey], Doc, null);
         return !dictation ? null : (
@@ -499,7 +582,7 @@ export class CollectionStackedTimeline extends CollectionSubView<
                 style={{
                     position: "absolute",
                     height: "100%",
-                    top: this.timelineContentHeight(),
+                    top: this.timelineContentHeight,
                     background: Colors.LIGHT_BLUE,
                 }}
             >
@@ -528,23 +611,22 @@ export class CollectionStackedTimeline extends CollectionSubView<
             </div>
         );
     }
-    @computed get renderAudioWaveform() {
-        return !this.props.mediaPath ? null : (
-            <div className="collectionStackedTimeline-waveform">
-                <AudioWaveform
-                    duration={this.duration}
-                    mediaPath={this.props.mediaPath}
-                    layoutDoc={this.layoutDoc}
-                    PanelHeight={this.timelineContentHeight}
-                    trimming={this.props.trimming}
-                />
-            </div>
+
+    // renders selection region on timeline
+    @computed get selectionContainer() {
+        const markerEnd = CollectionStackedTimeline.SelectingRegion === this ? this.currentTime : this._markerEnd;
+        return markerEnd === undefined ? null : (
+            <div
+                className="collectionStackedTimeline-selector"
+                style={{
+                    left: `${((Math.min(this._markerStart, markerEnd) - this.trimStart) / this.trimDuration) * 100}%`,
+                    width: `${(Math.abs(this._markerStart - markerEnd) / this.trimDuration) * 100}%`,
+                }}
+            />
         );
     }
 
-    currentTimecode = () => this.currentTime;
     render() {
-        const timelineContentWidth = this.props.PanelWidth();
         const overlaps: {
             anchorStartTime: number;
             anchorEndTime: number;
@@ -555,117 +637,133 @@ export class CollectionStackedTimeline extends CollectionSubView<
             anchor,
         }));
         const maxLevel = overlaps.reduce((m, o) => Math.max(m, o.level), 0) + 2;
-        const isActive =
-            this.props.isContentActive() || this.props.isSelected(false);
         return (<div ref={this.createDashEventsTarget} style={{ pointerEvents: SnappingManager.GetIsDragging() ? "all" : undefined }}>
-            <div
-                className="collectionStackedTimeline"
-                ref={(timeline: HTMLDivElement | null) => (this._timeline = timeline)}
-                onClick={(e) => isActive && StopEvent(e)}
-                onPointerDown={(e) => isActive && this.onPointerDownTimeline(e)}
-            >
-                {drawAnchors.map((d) => {
-
-                    const start = this.anchorStart(d.anchor);
-                    const end = this.anchorEnd(
-                        d.anchor,
-                        start + (10 / timelineContentWidth) * this.duration
-                    );
-                    const left = this.props.trimming ?
-                        (start / this.duration) * timelineContentWidth
-                        : (start - this.trimStart) / this.props.trimDuration * timelineContentWidth;
-                    const top = (d.level / maxLevel) * this.timelineContentHeight();
-                    const timespan = end - start;
-                    const width = (timespan / this.props.trimDuration) * timelineContentWidth;
-                    const height = this.timelineContentHeight() / maxLevel;
-                    return this.props.Document.hideAnchors ? null : (
-                        <div
-                            className={"collectionStackedTimeline-marker-timeline"}
-                            key={d.anchor[Id]}
-                            style={{
-                                left,
-                                top,
-                                width: `${width}px`,
-                                height: `${height}px`,
-                            }}
-                            onClick={(e) => {
-                                this.props.playFrom(start, this.anchorEnd(d.anchor));
-                                e.stopPropagation();
-                            }}
-                        >
-                            <StackedTimelineAnchor
-                                {...this.props}
-                                mark={d.anchor}
-                                rangeClickScript={this.rangeClickScript}
-                                rangePlayScript={this.rangePlayScript}
-                                left={left}
-                                top={top}
-                                width={width}
-                                height={height}
-                                toTimeline={this.toTimeline}
-                                layoutDoc={this.layoutDoc}
-                                currentTimecode={this.currentTimecode}
-                                _timeline={this._timeline}
-                                stackedTimeline={this}
-                                trimStart={this.trimStart}
-                                trimEnd={this.trimEnd}
-                            />
-                        </div>
-                    );
-                })}
-                {!this.props.trimming && this.selectionContainer}
-                {this.renderAudioWaveform}
-                {this.renderDictation}
-
+            <div className="timeline-container"
+                style={{ width: this.props.PanelWidth() }}
+                onWheel={e => e.stopPropagation()}
+                onScroll={this.setScroll}
+                ref={wrapper => this._timelineWrapper = wrapper}>
                 <div
-                    className="collectionStackedTimeline-current"
-                    style={{
-                        left: this.props.trimming
-                            ? `${(this.currentTime / this.duration) * 100}%`
-                            : `${(this.currentTime - this.trimStart) / (this.trimEnd - this.trimStart) * 100}%`,
-                    }}
-                />
-
-                {this.props.trimming && (
-                    <>
-                        <div
-                            className="collectionStackedTimeline-trim-shade"
-                            style={{ width: `${(this.trimStart / this.duration) * 100}%` }}
-                        ></div>
-
-                        <div
-                            className="collectionStackedTimeline-trim-controls"
-                            style={{
-                                left: `${(this.trimStart / this.duration) * 100}%`,
-                                width: `${((this.trimEnd - this.trimStart) / this.duration) * 100
-                                    }%`,
-                            }}
-                        >
+                    className="collectionStackedTimeline"
+                    ref={(timeline: HTMLDivElement | null) => (this._timeline = timeline)}
+                    onClick={(e) => this.isContentActive() && StopEvent(e)}
+                    onPointerDown={(e) => this.isContentActive() && this.onPointerDownTimeline(e)}
+                    style={{ width: this.timelineContentWidth }}>
+
+                    {drawAnchors.map((d) => {
+                        const start = this.anchorStart(d.anchor);
+                        const end = this.anchorEnd(
+                            d.anchor,
+                            start + (10 / this.timelineContentWidth) * this.clipDuration
+                        );
+                        if (end < this.clipStart || start > this.clipEnd) return (null);
+                        const left = Math.max((start - this.clipStart) / this.clipDuration * this.timelineContentWidth, 0);
+                        const top = (d.level / maxLevel) * this.props.PanelHeight();
+                        const timespan = Math.max(0, Math.min(end - this.clipStart, this.clipEnd)) - Math.max(0, start - this.clipStart);
+                        const width = (timespan / this.clipDuration) * this.timelineContentWidth;
+                        const height = this.props.PanelHeight() / maxLevel;
+                        return this.props.Document.hideAnchors ? null : (
                             <div
-                                className="collectionStackedTimeline-trim-handle"
-                                onPointerDown={this.trimLeft}
-                            ></div>
+                                className={"collectionStackedTimeline-marker-timeline"}
+                                key={d.anchor[Id]}
+                                style={{
+                                    left,
+                                    top,
+                                    width: `${width}px`,
+                                    height: `${height}px`,
+                                }}
+                                onClick={(e) => {
+                                    this.props.playFrom(start, this.anchorEnd(d.anchor));
+                                    e.stopPropagation();
+                                }}
+                            >
+                                <StackedTimelineAnchor
+                                    {...this.props}
+                                    mark={d.anchor}
+                                    rangeClickScript={this.rangeClickScript}
+                                    rangePlayScript={this.rangePlayScript}
+                                    left={left - this._scroll}
+                                    top={top}
+                                    width={width}
+                                    height={height}
+                                    toTimeline={this.toTimeline}
+                                    layoutDoc={this.layoutDoc}
+                                    // isDocumentActive={this.props.childDocumentsActive ? this.props.isDocumentActive : this.isContentActive}
+                                    currentTimecode={this.currentTimecode}
+                                    _timeline={this._timeline}
+                                    stackedTimeline={this}
+                                    trimStart={this.trimStart}
+                                    trimEnd={this.trimEnd}
+                                />
+                            </div>
+                        );
+                    })}
+                    {!this.IsTrimming && this.selectionContainer}
+                    <AudioWaveform
+                        rawDuration={this.props.rawDuration}
+                        duration={this.clipDuration}
+                        mediaPath={this.props.mediaPath}
+                        layoutDoc={this.layoutDoc}
+                        clipStart={this.clipStart}
+                        clipEnd={this.clipEnd}
+                        zoomFactor={this.zoomFactor}
+                        PanelHeight={this.timelineContentHeight}
+                        PanelWidth={this.timelineContentWidth}
+                    />
+                    {this.renderDictation}
+
+                    <div
+                        className="collectionStackedTimeline-current"
+                        style={{
+                            left: `${((this.currentTime - this.clipStart) / this.clipDuration) * 100}%`,
+                        }}
+                    />
+
+                    {this.IsTrimming !== TrimScope.None && (
+                        <>
                             <div
-                                className="collectionStackedTimeline-trim-handle"
-                                onPointerDown={this.trimRight}
+                                className="collectionStackedTimeline-trim-shade"
+                                style={{ width: `${((this.trimStart - this.clipStart) / this.clipDuration) * 100}%` }}
                             ></div>
-                        </div>
 
-                        <div
-                            className="collectionStackedTimeline-trim-shade"
-                            style={{
-                                left: `${(this.trimEnd / this.duration) * 100}%`,
-                                width: `${((this.duration - this.trimEnd) / this.duration) * 100
-                                    }%`,
-                            }}
-                        ></div>
-                    </>
-                )}
+                            <div
+                                className="collectionStackedTimeline-trim-controls"
+                                style={{
+                                    left: `${((this.trimStart - this.clipStart) / this.clipDuration) * 100}%`,
+                                    width: `${((this.trimEnd - this.trimStart) / this.clipDuration) * 100}%`,
+                                }}
+                            >
+                                <div
+                                    className="collectionStackedTimeline-trim-handle"
+                                    onPointerDown={this.trimLeft}
+                                ></div>
+                                <div
+                                    className="collectionStackedTimeline-trim-handle"
+                                    onPointerDown={this.trimRight}
+                                ></div>
+                            </div>
+
+                            <div
+                                className="collectionStackedTimeline-trim-shade"
+                                style={{
+                                    left: `${((this.trimEnd - this.clipStart) / this.clipDuration) * 100}%`,
+                                    width: `${((this.clipEnd - this.trimEnd) / this.clipDuration) * 100}%`,
+                                }}
+                            ></div>
+                        </>
+                    )}
+                </div>
             </div>
-        </div>);
+        </div >);
     }
 }
 
+
+/**
+ * StackedTimelineAnchor
+ * creates the anchors to display markers, links, and embedded documents on timeline
+ */
+
 interface StackedTimelineAnchorProps {
     mark: Doc;
     rangeClickScript: () => ScriptField;
@@ -681,6 +779,7 @@ interface StackedTimelineAnchorProps {
     endTag: string;
     renderDepth: number;
     layoutDoc: Doc;
+    isDocumentActive?: () => boolean;
     ScreenToLocalTransform: () => Transform;
     _timeline: HTMLDivElement | null;
     focus: DocFocusFunc;
@@ -690,14 +789,26 @@ interface StackedTimelineAnchorProps {
     trimStart: number;
     trimEnd: number;
 }
+
+
 @observer
 class StackedTimelineAnchor extends React.Component<StackedTimelineAnchorProps> {
     _lastTimecode: number;
     _disposer: IReactionDisposer | undefined;
+
     constructor(props: any) {
         super(props);
         this._lastTimecode = this.props.currentTimecode();
     }
+
+    // updates marker document title to reflect correct timecodes
+    computeTitle = () => {
+        const start = Math.max(NumCast(this.props.mark[this.props.startTag]), this.props.trimStart) - this.props.trimStart;
+        const end = Math.min(NumCast(this.props.mark[this.props.endTag]), this.props.trimEnd) - this.props.trimStart;
+        return `#${formatTime(start)}-${formatTime(end)}`;
+    }
+
+
     componentDidMount() {
         this._disposer = reaction(
             () => this.props.currentTimecode(),
@@ -718,6 +829,7 @@ class StackedTimelineAnchor extends React.Component<StackedTimelineAnchorProps>
                     // bcz: when should links be followed?  we don't want to move away from the video to follow a link but we can open it in a sidebar/etc.  But we don't know that upfront.
                     // for now, we won't follow any links when the lightbox is oepn to avoid "losing" the video.
                     /*(isDictation || !Doc.AreProtosEqual(LightboxView.LightboxDoc, this.props.layoutDoc))*/
+                    !this.props.layoutDoc.dontAutoFollowLinks &&
                     DocListCast(this.props.mark.links).length &&
                     time > NumCast(this.props.mark[this.props.startTag]) &&
                     time < NumCast(this.props.mark[this.props.endTag]) &&
@@ -735,9 +847,12 @@ class StackedTimelineAnchor extends React.Component<StackedTimelineAnchorProps>
             }
         );
     }
+
     componentWillUnmount() {
         this._disposer?.();
     }
+
+
     // starting the drag event for anchor resizing
     onAnchorDown = (e: React.PointerEvent, anchor: Doc, left: boolean): void => {
         this.props._timeline?.setPointerCapture(e.pointerId);
@@ -745,52 +860,59 @@ class StackedTimelineAnchor extends React.Component<StackedTimelineAnchorProps>
             const rect = (e.target as any).getBoundingClientRect();
             return this.props.toTimeline(e.clientX - rect.x, rect.width);
         };
-        const changeAnchor = (anchor: Doc, left: boolean, time: number) => {
-            const timelineOnly =
-                Cast(anchor[this.props.startTag], "number", null) !== undefined;
+        const changeAnchor = (anchor: Doc, left: boolean, time: number | undefined) => {
+            const timelineOnly = Cast(anchor[this.props.startTag], "number", null) !== undefined;
             if (timelineOnly) {
+                if (!left && time !== undefined && time <= NumCast(anchor[this.props.startTag])) time = undefined;
                 Doc.SetInPlace(
                     anchor,
                     left ? this.props.startTag : this.props.endTag,
                     time,
                     true
                 );
+                if (!left) Doc.SetInPlace(anchor, "borderRounding", time !== undefined ? undefined : "100%", true);
             }
             else {
-                left
-                    ? (anchor._timecodeToShow = time)
-                    : (anchor._timecodeToHide = time);
+                anchor[left ? "_timecodeToShow" : "_timecodeToHide"] = time;
             }
             return false;
         };
+        var undo: UndoManager.Batch | undefined;
+
         setupMoveUpEvents(
             this,
             e,
-            (e) => changeAnchor(anchor, left, newTime(e)),
+            (e) => {
+                if (!undo) undo = UndoManager.StartBatch("drag anchor");
+                this.props.setTime(newTime(e));
+                return changeAnchor(anchor, left, newTime(e));
+            },
             (e) => {
                 this.props.setTime(newTime(e));
                 this.props._timeline?.releasePointerCapture(e.pointerId);
+                undo?.end();
             },
             emptyFunction
         );
     }
 
-    @action
-    computeTitle = () => {
-        const start = Math.max(NumCast(this.props.mark[this.props.startTag]), this.props.trimStart) - this.props.trimStart;
-        const end = Math.min(NumCast(this.props.mark[this.props.endTag]), this.props.trimEnd) - this.props.trimStart;
-        return `#${formatTime(start)}-${formatTime(end)}`;
+
+    // context menu
+    contextMenuItems = () => {
+        const resetTitle = { script: ScriptField.MakeFunction(`self.title = "#" + formatToTime(self["${this.props.startTag}"]) + "-" + formatToTime(self["${this.props.endTag}"])`)!, icon: "folder-plus", label: "Reset Title" };
+        return [resetTitle];
     }
 
+
+    // renders anchor LabelBox
     renderInner = computedFn(function (
         this: StackedTimelineAnchor,
         mark: Doc,
         script: undefined | (() => ScriptField),
         doublescript: undefined | (() => ScriptField),
-        x: number,
-        y: number,
-        width: number,
-        height: number
+        screenXf: () => Transform,
+        width: () => number,
+        height: () => number
     ) {
         const anchor = observable({ view: undefined as any });
         const focusFunc = (
@@ -809,63 +931,62 @@ class StackedTimelineAnchor extends React.Component<StackedTimelineAnchorProps>
                 <DocumentView
                     key="view"
                     {...OmitKeys(this.props, ["NativeWidth", "NativeHeight"]).omit}
-                    ref={action((r: DocumentView | null) => (anchor.view = r))}
+                    ref={action((r: DocumentView | null) => anchor.view = r)}
                     Document={mark}
                     DataDoc={undefined}
                     renderDepth={this.props.renderDepth + 1}
                     LayoutTemplate={undefined}
                     LayoutTemplateString={LabelBox.LayoutStringWithTitle(LabelBox, "data", this.computeTitle())}
-                    isDocumentActive={returnFalse}
-                    PanelWidth={() => width}
-                    PanelHeight={() => height}
-                    ScreenToLocalTransform={() =>
-                        this.props.ScreenToLocalTransform().translate(-x, -y)
-                    }
+                    isDocumentActive={this.props.isDocumentActive}
+                    PanelWidth={width}
+                    PanelHeight={height}
+                    fitWidth={returnTrue}
+                    ScreenToLocalTransform={screenXf}
                     focus={focusFunc}
                     rootSelected={returnFalse}
                     onClick={script}
-                    onDoubleClick={
-                        this.props.layoutDoc.autoPlayAnchors ? undefined : doublescript
-                    }
+                    onDoubleClick={this.props.layoutDoc.autoPlayAnchors ? undefined : doublescript}
                     ignoreAutoHeight={false}
                     hideResizeHandles={true}
                     bringToFront={emptyFunction}
+                    contextMenuItems={this.contextMenuItems}
                     scriptContext={this.props.stackedTimeline}
                 />
             ),
         };
     });
 
+    anchorScreenToLocalXf = () => this.props.ScreenToLocalTransform().translate(-this.props.left, -this.props.top);
+    width = () => this.props.width;
+    height = () => this.props.height;
+
     render() {
         const inner = this.renderInner(
             this.props.mark,
             this.props.rangeClickScript,
             this.props.rangePlayScript,
-            this.props.left,
-            this.props.top,
-            this.props.width,
-            this.props.height
+            this.anchorScreenToLocalXf,
+            this.width,
+            this.height
         );
         return (
             <>
                 {inner.view}
                 {!inner.anchor.view ||
                     !SelectionManager.IsSelected(inner.anchor.view) ? null : (
-                        <>
-                            <div
-                                key="left"
-                                className="collectionStackedTimeline-left-resizer"
-                                onPointerDown={(e) => this.onAnchorDown(e, this.props.mark, true)}
-                            />
-                            <div
-                                key="right"
-                                className="collectionStackedTimeline-resizer"
-                                onPointerDown={(e) =>
-                                    this.onAnchorDown(e, this.props.mark, false)
-                                }
-                            />
-                        </>
-                    )}
+                    <>
+                        <div
+                            key="left"
+                            className="collectionStackedTimeline-left-resizer"
+                            onPointerDown={(e) => this.onAnchorDown(e, this.props.mark, true)}
+                        />
+                        <div
+                            key="right"
+                            className="collectionStackedTimeline-resizer"
+                            onPointerDown={(e) => this.onAnchorDown(e, this.props.mark, false)}
+                        />
+                    </>
+                )}
             </>
         );
     }