realistic timestamps option

gpx/src/gpx.ts

@@ -350,6 +350,15 @@ export class GPXFile extends GPXTreeNode<Track>{
         });
     }
 
+    createArtificialTimestamps(startTime: Date, totalTime: number, trackIndex?: number, segmentIndex?: number) {
+        let lastPoint = undefined;
+        this.trk.forEach((track, index) => {
+            if (trackIndex === undefined || trackIndex === index) {
+                track.createArtificialTimestamps(startTime, totalTime, lastPoint, segmentIndex);
+            }
+        });
+    }
+
     setStyle(style: LineStyleExtension) {
         this.trk.forEach((track) => {
             track.setStyle(style);
@@ -581,6 +590,17 @@ export class Track extends GPXTreeNode<TrackSegment> {
         });
     }
 
+    createArtificialTimestamps(startTime: Date, totalTime: number, lastPoint: TrackPoint | undefined, segmentIndex?: number) {
+        this.trkseg.forEach((segment, index) => {
+            if (segmentIndex === undefined || segmentIndex === index) {
+                segment.createArtificialTimestamps(startTime, totalTime, lastPoint);
+                if (segment.trkpt.length > 0) {
+                    lastPoint = segment.trkpt[segment.trkpt.length - 1];
+                }
+            }
+        });
+    }
+
     setStyle(style: LineStyleExtension, force: boolean = true) {
         if (!this.extensions) {
             this.extensions = {};
@@ -944,6 +964,14 @@ export class TrackSegment extends GPXTreeLeaf {
             this.trkpt = freeze(trkpt); // Pre-freeze the array, faster as well
         }
     }
+
+    createArtificialTimestamps(startTime: Date, totalTime: number, lastPoint: TrackPoint | undefined) {
+        let og = getOriginal(this); // Read as much as possible from the original object because it is faster
+        let slope = og._computeSlope();
+        let trkpt = withArtificialTimestamps(og.trkpt, totalTime, lastPoint, startTime, slope);
+        this.trkpt = freeze(trkpt); // Pre-freeze the array, faster as well
+    }
+
     setHidden(hidden: boolean) {
         this._data.hidden = hidden;
     }
@@ -1442,6 +1470,30 @@ function withShiftedAndCompressedTimestamps(points: TrackPoint[], speed: number,
     });
 }
 
+function withArtificialTimestamps(points: TrackPoint[], totalTime: number, lastPoint: TrackPoint | undefined, startTime: Date, slope: number[]): TrackPoint[] {
+    let weight = [];
+    let totalWeight = 0;
+
+    for (let i = 0; i < points.length - 1; i++) {
+        let dist = distance(points[i].getCoordinates(), points[i + 1].getCoordinates());
+        let w = dist * (0.5 + 1 / (1 + Math.exp(- 0.2 * slope[i])));
+        weight.push(w);
+        totalWeight += w;
+    }
+
+    let last = lastPoint;
+    return points.map((point, i) => {
+        let pt = point.clone();
+        if (i === 0) {
+            pt.time = lastPoint?.time ?? startTime;
+        } else {
+            pt.time = new Date(last.time.getTime() + totalTime * 1000 * weight[i - 1] / totalWeight);
+        }
+        last = pt;
+        return pt;
+    });
+}
+
 function getTimestamp(a: TrackPoint, b: TrackPoint, speed: number): Date {
     let dist = distance(a.getCoordinates(), b.getCoordinates()) / 1000;
     return new Date(a.time.getTime() + 1000 * 3600 * dist / speed);

website/src/lib/components/toolbar/tools/Time.svelte

@@ -33,6 +33,7 @@
     let endTime: string | undefined = undefined;
     let movingTime: number | undefined = undefined;
     let speed: number | undefined = undefined;
+    let artificial = false;
 
     function toCalendarDate(date: Date): CalendarDate {
         return new CalendarDate(date.getFullYear(), date.getMonth() + 1, date.getDate());
@@ -281,8 +282,8 @@
             />
         </div>
         {#if $gpxStatistics.global.time.moving === 0 || $gpxStatistics.global.time.moving === undefined}
-			<div class="mt-0.5 flex flex-row gap-1 items-center hidden">
+            <div class="mt-0.5 flex flex-row gap-1 items-center">
-				<Checkbox id="artificial-time" disabled={!canUpdate} />
+                <Checkbox id="artificial-time" bind:checked={artificial} disabled={!canUpdate} />
                 <Label for="artificial-time">
                     {$_('toolbar.time.artificial')}
                 </Label>
@@ -296,7 +297,11 @@
             class="grow"
             on:click={() => {
                 let effectiveSpeed = getSpeed();
-				if (startDate === undefined || startTime === undefined || effectiveSpeed === undefined) {
+                if (
+                    startDate === undefined ||
+                    startTime === undefined ||
+                    effectiveSpeed === undefined
+                ) {
                     return;
                 }
 
@@ -316,15 +321,42 @@
                 let fileId = item.getFileId();
                 dbUtils.applyToFile(fileId, (file) => {
                     if (item instanceof ListFileItem) {
-						file.changeTimestamps(getDate(startDate, startTime), effectiveSpeed, ratio);
+                        if (artificial) {
+                            file.createArtificialTimestamps(
+                                getDate(startDate, startTime),
+                                movingTime
+                            );
+                        } else {
+                            file.changeTimestamps(
+                                getDate(startDate, startTime),
+                                effectiveSpeed,
+                                ratio
+                            );
+                        }
                     } else if (item instanceof ListTrackItem) {
+                        if (artificial) {
+                            file.createArtificialTimestamps(
+                                getDate(startDate, startTime),
+                                movingTime,
+                                item.getTrackIndex()
+                            );
+                        } else {
                             file.changeTimestamps(
                                 getDate(startDate, startTime),
                                 effectiveSpeed,
                                 ratio,
                                 item.getTrackIndex()
                             );
+                        }
                     } else if (item instanceof ListTrackSegmentItem) {
+                        if (artificial) {
+                            file.createArtificialTimestamps(
+                                getDate(startDate, startTime),
+                                movingTime,
+                                item.getTrackIndex(),
+                                item.getSegmentIndex()
+                            );
+                        } else {
                             file.changeTimestamps(
                                 getDate(startDate, startTime),
                                 effectiveSpeed,
@@ -333,6 +365,7 @@
                                 item.getSegmentIndex()
                             );
                         }
+                    }
                 });
             }}
         >