Migrate to Maplibre GL with WebGL-based rendering

package.json

@@ -10,6 +10,8 @@
   },
   "dependencies": {
     "@turf/along": "^6.3.0",
+    "@turf/bearing": "^6.5.0",
+    "@turf/clone": "^6.5.0",
     "@turf/helpers": "^6.3.0",
     "@turf/length": "^6.3.0",
     "@turf/projection": "^6.3.0",
@@ -19,7 +21,7 @@
     "csv-parse": "^4.15.4",
     "dijkstrajs": "^1.0.1",
     "express": "^4.17.1",
-    "ol": "^6.5.0",
+    "maplibre-gl": "^2.1.9",
     "unzip-stream": "^0.3.1",
     "vue": "^3.0.5"
   },

src/data/simulation.js

@@ -1,5 +1,6 @@
 import axios from "axios";
 import turfAlong from "@turf/along";
+import turfBearing from "@turf/bearing";
 import * as turfProjection from "@turf/projection";
 import * as routing from "./routing.js";
 import network from "./network.json";
@@ -21,188 +22,208 @@ const minSpeed = 10 / 3600;
 // Normal speed of a vehicle
 const normSpeed = (2 * maxSpeed + minSpeed) / 3;
 
-/** Simulate the evolution of a vehicle course in the network. */
+/**
+ * GeoJSON feature representing a vehicle course with simulation of the
+ * vehicle’s movement along the course.
+ */
 class Course {
     constructor(id) {
+        this.type = "Feature";
+
+        // Current vehicle position (latitude and longitude)
+        this.geometry = {};
+        this.geometry.type = "Point";
+        this.geometry.coordinates = [0, 0];
+
+        this.properties = {};
+
         // Unique identifier of this course
-        this.id = id;
+        this.properties.id = id;
 
         // Line on which this vehicle operates
-        this.line = null;
+        this.properties.line = null;
 
         // Line direction of this course
-        this.direction = null;
+        this.properties.direction = null;
 
         // Stop to which this course is headed
-        this.finalStop = null;
+        this.properties.finalStop = null;
 
         // Previous stops that this course left (stop id/timestamp pairs)
-        this.prevPassings = [];
+        this.properties.prevPassings = [];
 
         // Next stops that this course will leave (stop id/timestamp pairs)
-        this.nextPassings = [];
+        this.properties.nextPassings = [];
 
         // Stop that this course just left or will leave
-        this.departureStop = null;
+        this.properties.departureStop = null;
 
         // Time at which the last stop was left or will be left (timestamp)
-        this.departureTime = 0;
+        this.properties.departureTime = 0;
 
         // Next stop that this course will reach
-        this.arrivalStop = null;
+        this.properties.arrivalStop = null;
 
         // Time at which the next stop will be left (timestamp)
-        this.arrivalTime = 0;
+        this.properties.arrivalTime = 0;
 
         // Route between the current departure and arrival stops
-        this.segment = null;
+        this.properties.segment = null;
 
         // Distance already travelled between the two stops (meters)
-        this.traveledDistance = 0;
+        this.properties.traveledDistance = 0;
 
         // Current vehicle speed (meters per millisecond)
-        this.speed = 0;
-
-        // Current vehicle latitude and longitude
-        this.position = [0, 0];
+        this.properties.speed = 0;
 
         // Current vehicle bearing (clockwise degrees from north)
-        this.angle = 0;
+        this.properties.bearing = 0;
     }
 
     /** Find a route between the current departure and arrival stops. */
     updateSegment() {
-        if (this.departureStop === null || this.arrivalStop === null) {
-            this.segment = null;
+        const props = this.properties;
+
+        if (props.departureStop === null || props.arrivalStop === null) {
+            props.segment = null;
             return;
         }
 
-        const name = `${this.departureStop}-${this.arrivalStop}`;
+        const name = `${props.departureStop}-${props.arrivalStop}`;
 
-        if (!(this.departureStop in network.stops)) {
-            console.warn(`Unknown stop: ${this.departureStop}`);
-            this.segment = null;
+        if (!(props.departureStop in network.stops)) {
+            console.warn(`Unknown stop: ${props.departureStop}`);
+            props.segment = null;
             return;
         }
 
-        if (!(this.arrivalStop in network.stops)) {
-            console.warn(`Unknown stop: ${this.arrivalStop}`);
-            this.segment = null;
+        if (!(props.arrivalStop in network.stops)) {
+            console.warn(`Unknown stop: ${props.arrivalStop}`);
+            props.segment = null;
             return;
         }
 
         // Compute a custom route between two stops
-        this.segment = routing.findSegment(this.departureStop, this.arrivalStop);
+        props.segment = routing.findSegment(
+            props.departureStop,
+            props.arrivalStop,
+        );
 
-        if (this.segment === null) {
-            console.warn(`No route from ${this.departureStop} \
-to ${this.arrivalStop}`);
+        if (props.segment === null) {
+            console.warn(`No route from ${props.departureStop} \
+to ${props.arrivalStop}`);
         }
     }
 
     /** Merge passings data received from the server. */
     receiveData(data) {
-        this.line = data.line;
-        this.direction = data.direction;
-        this.finalStop = data.finalStopId;
+        const props = this.properties;
+
+        props.line = data.line;
+        props.direction = data.direction;
+        props.finalStop = data.finalStopId;
 
         const passings = Object.assign(
-            Object.fromEntries(this.nextPassings),
+            Object.fromEntries(props.nextPassings),
             Object.fromEntries(data.passings),
         );
 
         // Remove older passings from next passings
-        for (let [stop, _] of this.prevPassings) {
+        for (let [stop, _] of props.prevPassings) {
             delete passings[stop];
         }
 
         // Update departure time if still announced
-        if (this.departureStop !== null) {
-            if (this.departureStop in passings) {
-                this.departureTime = passings[this.departureStop];
-                delete passings[this.departureStop];
+        if (props.departureStop !== null) {
+            if (props.departureStop in passings) {
+                props.departureTime = passings[props.departureStop];
+                delete passings[props.departureStop];
             }
         }
 
         // Update arrival time
-        if (this.arrivalStop !== null) {
-            if (this.arrivalStop in passings) {
+        if (props.arrivalStop !== null) {
+            if (props.arrivalStop in passings) {
                 // Use announced time if available
-                this.arrivalTime = passings[this.arrivalStop];
-                delete passings[this.arrivalStop];
+                props.arrivalTime = passings[props.arrivalStop];
+                delete passings[props.arrivalStop];
             } else {
                 // Otherwise, arrive using a normal speed from current position
-                const segment = this.segment;
-                const distance = segment.properties.length - this.traveledDistance;
+                const segment = props.segment;
+                const distance = segment.properties.length - props.traveledDistance;
                 const time = Math.floor(distance / normSpeed);
-                this.arrivalTime = Date.now() + time;
+                props.arrivalTime = Date.now() + time;
             }
         }
 
-        this.nextPassings = Object.entries(passings).sort(
+        props.nextPassings = Object.entries(passings).sort(
             ([, time1], [, time2]) => time1 - time2
         );
     }
 
     /** Update the vehicle state. */
     update() {
+        const props = this.properties;
         const now = Date.now();
 
         // When initializing, use the first available passing as start
-        if (this.departureStop === null) {
-            if (this.nextPassings.length > 0) {
-                const [stopId, time] = this.nextPassings.shift();
-                this.departureStop = stopId;
-                this.departureTime = time;
+        if (props.departureStop === null) {
+            if (props.nextPassings.length > 0) {
+                const [stopId, time] = props.nextPassings.shift();
+                props.departureStop = stopId;
+                props.departureTime = time;
                 this.updateSegment();
             }
         }
 
         // …and the second one as the arrival
-        if (this.arrivalStop === null) {
-            if (this.nextPassings.length > 0) {
-                const [stopId, time] = this.nextPassings.shift();
-                this.arrivalStop = stopId;
-                this.arrivalTime = time;
+        if (props.arrivalStop === null) {
+            if (props.nextPassings.length > 0) {
+                const [stopId, time] = props.nextPassings.shift();
+                props.arrivalStop = stopId;
+                props.arrivalTime = time;
                 this.updateSegment();
             }
         }
 
-        if (this.segment !== null) {
-            const segment = this.segment;
-            const distance = segment.properties.length - this.traveledDistance;
-            const duration = this.arrivalTime - stopTime - now;
+        if (props.segment !== null) {
+            const segment = props.segment;
+            const distance = segment.properties.length - props.traveledDistance;
+            const duration = props.arrivalTime - stopTime - now;
 
             // Arrive to the next stop
             if (distance === 0) {
-                this.prevPassings.push([this.departureStop, this.departureTime]);
-                this.departureStop = this.arrivalStop;
-                this.departureTime = this.arrivalTime;
+                props.prevPassings.push([
+                    props.departureStop,
+                    props.departureTime
+                ]);
+                props.departureStop = props.arrivalStop;
+                props.departureTime = props.arrivalTime;
 
-                if (this.nextPassings.length > 0) {
-                    const [stopId, time] = this.nextPassings.shift();
-                    this.arrivalStop = stopId;
-                    this.arrivalTime = time;
+                if (props.nextPassings.length > 0) {
+                    const [stopId, time] = props.nextPassings.shift();
+                    props.arrivalStop = stopId;
+                    props.arrivalTime = time;
                 } else {
-                    this.arrivalStop = null;
-                    this.arrivalTime = 0;
+                    props.arrivalStop = null;
+                    props.arrivalTime = 0;
                 }
 
-                this.traveledDistance = 0;
+                props.traveledDistance = 0;
                 this.updateSegment();
             }
 
-            if (this.departureTime > now) {
+            if (props.departureTime > now) {
                 // Wait for departure
-                this.speed = 0;
+                props.speed = 0;
             } else {
-                if (this.traveledDistance === 0 && this.speed === 0) {
+                if (props.traveledDistance === 0 && props.speed === 0) {
                     // We’re late, record the actual departure time
-                    this.departureTime = now;
+                    props.departureTime = now;
                 }
 
                 // Update current speed to arrive on time if possible
-                this.speed = Course.computeSpeed(distance, duration);
+                props.speed = Course.computeSpeed(distance, duration);
             }
         }
 
@@ -211,44 +232,49 @@ to ${this.arrivalStop}`);
 
     /** Integrate the current vehicle speed and update distance. */
     move(time) {
-        if (this.segment === null) {
+        const props = this.properties;
+        const segment = props.segment;
+
+        if (props.segment === null) {
             return;
         }
 
-        if (this.speed > 0) {
-            this.traveledDistance = Math.min(
-                this.traveledDistance + this.speed * time,
-                this.segment.properties.length,
+        if (props.speed > 0) {
+            props.traveledDistance = Math.min(
+                props.traveledDistance + props.speed * time,
+                segment.properties.length,
             );
         }
 
-        // Compute updated position and angle based on a small step
+        // Compute angle based on a small step along the segment
         let positionBehind;
-        let positionInFront;
+        let positionAhead;
 
-        if (this.traveledDistance < angleStep / 2) {
-            positionBehind = this.traveledDistance;
-            positionInFront = angleStep;
+        if (props.traveledDistance < angleStep / 2) {
+            positionBehind = props.traveledDistance;
+            positionAhead = angleStep;
         } else {
-            positionBehind = this.traveledDistance - angleStep / 2;
-            positionInFront = this.traveledDistance + angleStep / 2;
+            positionBehind = props.traveledDistance - angleStep / 2;
+            positionAhead = props.traveledDistance + angleStep / 2;
         }
 
         const positions = [
             positionBehind,
-            this.traveledDistance,
-            positionInFront,
-        ].map(distance => turfProjection.toMercator(turfAlong(
-            this.segment,
+            props.traveledDistance,
+            positionAhead,
+        ].map(distance => turfAlong(
+            props.segment,
             distance / 1000
-        )).geometry.coordinates);
+        ));
 
-        this.angle = Math.atan2(
-            positions[0][1] - positions[2][1],
-            positions[2][0] - positions[0][0]
-        );
+        this.geometry.coordinates = positions[1].geometry.coordinates;
+        props.bearing = turfBearing(positions[0], positions[2]);
+    }
 
-        this.position = positions[1];
+    /** Check if a course is finished. */
+    isFinished() {
+        const props = this.properties;
+        return props.departureStop === props.finalStop;
     }
 
     /**
@@ -291,7 +317,7 @@ const updateData = async courses => {
 
     // Remove stale courses
     for (const id of Object.keys(courses)) {
-        if (courses[id].departureStop === courses[id].finalStop) {
+        if (courses[id].isFinished()) {
             delete courses[id];
         }
     }

src/front/index.js

@@ -12,11 +12,10 @@ window.__network = network;
 // Create display panel
 const panel = document.querySelector("#panel");
 
-const displayTime = date => [
-    date.getHours(),
-    date.getMinutes(),
-    date.getSeconds()
-].map(number => number.toString().padStart(2, "0")).join(":");
+const timeFormat = new Intl.DateTimeFormat("fr-FR", {
+    timeZone: "Europe/Paris",
+    timeStyle: "medium",
+});
 
 const timeToHTML = time => {
     const delta = Math.ceil((time - Date.now()) / 1000);
@@ -31,10 +30,22 @@ const timeToHTML = time => {
 };
 
 setInterval(() => {
+    const vehicleCount = Object.values(coursesSimulation.courses).length;
+    const movingVehicles = Object.values(coursesSimulation.courses).filter(
+        course => course.properties.speed > 0
+    ).length;
+
     let html = `
         <dl>
-            <dt>Heure actuelle</dt>
-            <dd>${displayTime(new Date())}</dd>
+            <dt>Heure locale</dt>
+            <dd>${timeFormat.format(Date.now())}</dd>
+        </dl>
+        <dl>
+            <dt>Véhicules sur la carte</dt>
+            <dd>
+                ${movingVehicles} en mouvement,
+                ${vehicleCount - movingVehicles} à l’arrêt
+            </dd>
         </dl>
     `;
 
@@ -48,7 +59,7 @@ setInterval(() => {
         const passingsToHTML = passings => passings.map(([stopId, time]) => `
             <tr>
                 <td>${stopToHTML(stopId)}</td>
-                <td>${displayTime(new Date(time))}</td>
+                <td>${timeFormat.format(time)}</td>
             </tr>
         `).join("\n");
 
@@ -107,7 +118,7 @@ setInterval(() => {
 }, 1000);
 
 // Create the network and courses map
-map.create(/* map = */ "map", coursesSimulation, courses => {
+window.__map = map.create(/* map = */ "map", coursesSimulation, courses => {
     const index = courses.indexOf(selectedCourse);
 
     if (courses.length === 0) {

src/front/map/common.js

@@ -1,5 +1,14 @@
 import color from "color";
 
+/** Make a value scale according to the zoom level. */
+export const scaleZoom = value => [
+    "interpolate",
+    ["exponential", 2],
+    ["zoom"],
+    10, value,
+    24, ["*", value, ["^", 2, 6]]
+];
+
 /**
  * Turn the main color of a line into a color suitable for using as a border.
  * @param {string} mainColor Original color.
@@ -40,9 +49,9 @@ export const cacheStyle = (createStyle, cacheKey = x => x) => {
 
 export const sizes = {
     segmentOuter: 8,
-    segmentInner: 6,
-    stopRadius: 6,
-    stopBorder: 1.5,
+    segmentInner: 12,
+    stopOuter: 8,
+    stopInner: 6,
     courseSize: 15,
     courseOuterBorder: 13,
     courseBorder: 10,

src/front/map/courses.js

@@ -1,139 +0,0 @@
-import { getVectorContext } from "ol/render";
-import Point from "ol/geom/Point";
-import { fromExtent } from 'ol/geom/Polygon';
-import { Style, Icon } from "ol/style";
-import { sizes, cacheStyle, makeBorderColor, makeCourseColor } from "./common";
-import network from "../../data/network.json";
-
-const courseStyle = cacheStyle(
-    lineColor => {
-        const icon = window.document.createElement("canvas");
-
-        const shapeSize = sizes.courseSize;
-        const iconSize = sizes.courseSize + sizes.courseOuterBorder;
-
-        icon.width = iconSize;
-        icon.height = iconSize;
-
-        const cx = icon.width / 2;
-        const cy = icon.height / 2;
-
-        const iconCtx = icon.getContext("2d");
-
-        for (const [color, size] of [
-            [makeBorderColor(lineColor), sizes.courseOuterBorder],
-            [lineColor, sizes.courseBorder],
-            [makeCourseColor(lineColor), sizes.courseInnerBorder]
-        ]) {
-            iconCtx.fillStyle = color;
-            iconCtx.strokeStyle = color;
-            iconCtx.lineWidth = size;
-            iconCtx.lineJoin = "round";
-            iconCtx.miterLimit = 200000;
-
-            iconCtx.beginPath();
-            iconCtx.moveTo(cx - 0.5 * shapeSize, cy - 0.3 * shapeSize);
-            iconCtx.lineTo(cx + 0.5 * shapeSize, cy);
-            iconCtx.lineTo(cx - 0.5 * shapeSize, cy + 0.3 * shapeSize);
-            iconCtx.closePath();
-            iconCtx.stroke();
-            iconCtx.fill();
-        }
-
-        return new Style({
-            image: new Icon({
-                img: icon,
-                imgSize: [icon.width, icon.height]
-            })
-        });
-    },
-);
-
-export const setupCoursesAnimation = (
-    map, coursesSimulation, stopsLayer, onClick
-) => {
-    const view = map.getView();
-
-    // Draw courses directly on the map
-    map.on("postcompose", ev => {
-        coursesSimulation.update();
-
-        // The normal way to access a layer’s vector context is through the
-        // `postrender` event of that layer. However, `postrender` is not
-        // triggered when no feature of the layer is inside the current
-        // bounding box, but we want to draw vehicles in between stops even
-        // if no stop is visible. This hack listens to the global `postcompose`
-        // event, which is always triggered at every frame, and reconstructs
-        // the stops layer’s vector context from internal variables
-        /* eslint-disable no-underscore-dangle */
-        if (stopsLayer.renderer_) {
-            ev.context = stopsLayer.renderer_.context;
-            ev.inversePixelTransform =
-                stopsLayer.renderer_.inversePixelTransform;
-            /* eslint-enable no-underscore-dangle */
-
-            const ctx = getVectorContext(ev);
-            const bbox = fromExtent(map.getView().calculateExtent());
-            bbox.scale(1.05);
-
-            for (const course of Object.values(coursesSimulation.courses)) {
-                if (!bbox.intersectsCoordinate(course.position)) {
-                    continue;
-                }
-
-                const point = new Point(course.position);
-                const color = network.lines[course.line].color;
-                const style = courseStyle(color);
-
-                style.getImage().setRotation(
-                    view.getRotation() +
-                    course.angle
-                );
-
-                ctx.setStyle(style);
-                ctx.drawGeometry(point);
-            }
-        }
-
-        map.render();
-    });
-
-    map.on("singleclick", ev => {
-        const mousePixel = map.getPixelFromCoordinate(ev.coordinate);
-        const maxDistance = sizes.courseSize + sizes.courseInnerBorder;
-        const clicked = [];
-
-        for (const course of Object.values(coursesSimulation.courses)) {
-            const coursePixel = map.getPixelFromCoordinate(course.position);
-            const dx = mousePixel[0] - coursePixel[0];
-            const dy = mousePixel[1] - coursePixel[1];
-            const distance = dx * dx + dy * dy;
-
-            if (distance <= maxDistance * maxDistance) {
-                clicked.push(course.id);
-            }
-        }
-
-        // Sort selected courses in increasing departing/arrival time
-        clicked.sort((id1, id2) => {
-            const course1 = coursesSimulation.courses[id1];
-            const course2 = coursesSimulation.courses[id2];
-
-            const time1 = (
-                course1.state === "moving"
-                ? course1.arrivalTime
-                : course1.departureTime
-            );
-
-            const time2 = (
-                course2.state === "moving"
-                ? course2.arrivalTime
-                : course2.departureTime
-            );
-
-            return time1 - time2;
-        });
-
-        onClick(clicked);
-    });
-};

src/front/map/index.js

@@ -1,31 +1,48 @@
-import "ol/ol.css";
+import "maplibre-gl/dist/maplibre-gl.css";
+import { Map, NavigationControl } from "maplibre-gl";
 
-import { Map, View } from "ol";
-import * as proj from "ol/proj";
-import { getLayers as getTilesLayers } from "./tiles";
-import { getLayers as getNetworkLayers } from "./network";
-import { setupCoursesAnimation } from "./courses";
+import * as network from "./network";
+import * as vehicles from "./vehicles";
+import style from "./assets/style.json";
 
-export const create = (target, coursesSimulation, onClick) => {
-    const view = new View({
-        center: proj.fromLonLat([3.88, 43.605]),
-        zoom: 14,
-        maxZoom: 22,
-        constrainResolution: true
-    });
+const mapId = "c1309cde-1b6e-4c9b-8b65-48512757d354";
+const mapKey = "6T8Cb9oYBFeDjDhpmNmd";
 
-    const tilesLayers = getTilesLayers();
-    const networkLayers = getNetworkLayers();
-    const stopsLayer = networkLayers[2];
+style.sources.openmaptiles.url = style.sources.openmaptiles.url.replace("{key}", mapKey);
+style.glyphs = style.glyphs.replace("{key}", mapKey);
 
+const bounds = [
+    "3.660507202148437", "43.49552248630757",
+    "4.092750549316406", "43.73736766145917",
+];
+
+export const create = (target, simulation, onClick) => {
     const map = new Map({
-        target,
-        layers: [...tilesLayers, ...networkLayers],
-        view
+        container: target,
+        style,
+        bounds,
+
+        maplibreLogo: true,
+        maxPitch: 70,
     });
 
-    setupCoursesAnimation(map, coursesSimulation, stopsLayer, onClick);
-    map.render();
+    map.addControl(new NavigationControl());
+
+    const animate = () => {
+        simulation.update();
+        vehicles.update(map, simulation.courses);
+        requestAnimationFrame(animate);
+    };
+
+    map.on("load", () => {
+        network.addLayers(map);
+        vehicles.addLayers(map);
+
+        // Move 3D buildings to the front of custom layers
+        map.moveLayer("building-3d");
+
+        animate();
+    });
 
     return map;
 };

src/front/map/network.js

@@ -1,146 +1,170 @@
+import * as turfHelpers from "@turf/helpers";
+import turfClone from "@turf/clone";
+
 import network from "../../data/network.json";
 import * as routing from "../../data/routing.js";
-import { cacheStyle, makeBorderColor, sizes } from "./common";
+import { makeBorderColor, scaleZoom } from "./common";
 
-import GeoJSON from "ol/format/GeoJSON";
-import VectorImageLayer from "ol/layer/VectorImage";
-import VectorSource from "ol/source/Vector";
+const MIN_ZOOM_SEGMENTS = 9;
+const MIN_ZOOM_STOPS = 11;
+const MAX_ZOOM = 22;
 
-import { Style, Fill, Stroke, Circle } from "ol/style";
+const BORDER_SIZE = 3;
+const SEGMENT_SIZE = 6;
+const STOP_SIZE = 12;
 
-const geojsonReader = new GeoJSON({ featureProjection: "EPSG:3857" });
-
-// Style used for the border of line segments
-const segmentBorderStyle = cacheStyle(
-    color => new Style({
-        stroke: new Stroke({
-            color: makeBorderColor(color),
-            width: sizes.segmentOuter
-        })
-    }),
-    feature => feature.get("colors")[0],
+/** Compute a line offset to share a line span with other adjacent lines. */
+const getOffset = (size, index, count) => (
+    -size / 2
+    + size / count / 2
+    + index * size / count
 );
 
-// Style used for the inner part of line segments
-const segmentInnerStyle = cacheStyle(
-    color => new Style({
-        stroke: new Stroke({
-            color,
-            width: sizes.segmentInner
-        })
-    }),
-    feature => feature.get("colors")[0],
-);
+/** Get the collection of line segments. */
+const getSegments = () => {
+    // Aggregate segments spanning multiple routes
+    const groupedSegments = {};
 
-// Style used for line stops
-const stopStyle = cacheStyle(
-    color => new Style({
-        image: new Circle({
-            fill: new Fill({ color }),
-            stroke: new Stroke({
-                color: makeBorderColor(color),
-                width: sizes.stopBorder
-            }),
-            radius: sizes.stopRadius
-        })
-    }),
-    feature => feature.get("colors")[0],
-);
+    for (const [lineRef, line] of Object.entries(network.lines)) {
+        for (const route of line.routes) {
+            for (let i = 0; i + 1 < route.stops.length; ++i) {
+                const stop1 = network.stops[route.stops[i]].id;
+                const stop2 = network.stops[route.stops[i + 1]].id;
 
-/**
- * Order for features related to a network line inside the same layer.
- * @param {Feature} feature1 First feature to order.
- * @param {Feature} feature2 Second feature to order.
- * @returns {number} -1 if `feature1` comes before `feature2`, 1 if
- * `feature2` comes before `feature1`, 0 if the order is irrelevant.
- */
-const lineFeaturesOrder = (feature1, feature2) => {
-    // Place features with no lines attributed on the background
-    const lines1 = feature1.get("lines");
+                const waypoints = routing.findPath(stop1, stop2);
 
-    if (lines1.length === 0) {
-        return -1;
-    }
+                for (let j = 0; j + 1 < waypoints.length; ++j) {
+                    const point1 = waypoints[j];
+                    const point2 = waypoints[j + 1];
+                    const id = `${point1}-${point2}`;
 
-    const lines2 = feature2.get("lines");
-
-    if (lines2.length === 0) {
-        return 1;
-    }
-
-    // Draw lines with a lower numeric value first
-    return Math.max(...lines2) - Math.max(...lines1);
-};
-
-/**
- * Create the list of layers for displaying the transit network.
- * @returns {Array.<Layer>} List of map layers.
- */
-export const getLayers = () => {
-    const segmentsSource = new VectorSource();
-    const stopsSource = new VectorSource();
-
-    // Turn GeoJSON stops list into a vector source
-    const readStops = hash => Object.values(hash).map(json => {
-        json.properties.lines = json.properties.routes.map(([lineRef]) => lineRef);
-
-        if (json.properties.lines.length >= 1) {
-            json.properties.colors = json.properties.lines.map(
-                lineRef => network.lines[lineRef].color
-            );
-        } else {
-            json.properties.colors = ["#FFFFFF"];
-        }
-
-        return geojsonReader.readFeature(json);
-    });
-
-    stopsSource.addFeatures(readStops(network.stops));
-
-    // Link stops with segments
-    const makeSegments = function* (lines) {
-        for (const [lineRef, line] of Object.entries(network.lines)) {
-            for (const route of line.routes) {
-                for (let i = 0; i + 1 < route.stops.length; ++i) {
-                    const stop1 = network.stops[route.stops[i]].id;
-                    const stop2 = network.stops[route.stops[i + 1]].id;
-
-                    const segment = routing.findSegment(stop1, stop2);
-                    segment.properties.lines = [lineRef];
-                    segment.properties.colors = [line.color];
-
-                    yield geojsonReader.readFeature(segment);
+                    if (id in groupedSegments) {
+                        groupedSegments[id].properties.lines.add(lineRef);
+                    } else {
+                        groupedSegments[id] = (
+                            turfClone(network.navigation[point1][point2])
+                        );
+                        groupedSegments[id].properties.lines = new Set();
+                        groupedSegments[id].properties.lines.add(lineRef);
+                    }
                 }
             }
         }
-    };
+    }
 
-    segmentsSource.addFeatures([...makeSegments(network.lines)]);
+    const segments = [];
 
-    // Background layer on which the darker borders of line segments are drawn
-    const segmentsBorderLayer = new VectorImageLayer({
-        source: segmentsSource,
-        renderOrder: lineFeaturesOrder,
-        style: segmentBorderStyle,
-        imageRatio: 2,
-    });
+    for (const segment of Object.values(groupedSegments)) {
+        const lines = [...segment.properties.lines];
+        lines.sort();
+        const count = lines.length;
 
-    // Foreground layer on which the lighter inner part of line segments are
-    // drawn. The two layers are separated so that forks blend nicely together
-    const segmentsInnerLayer = new VectorImageLayer({
-        source: segmentsSource,
-        renderOrder: lineFeaturesOrder,
-        style: segmentInnerStyle,
-        imageRatio: 2,
-    });
+        // Duplicate and offset segments for each route
+        for (const [index, line] of lines.entries()) {
+            const feature = turfClone(segment);
+            const props = feature.properties;
+            delete props.lines;
+            props.line = line;
 
-    const stopsLayer = new VectorImageLayer({
-        source: stopsSource,
-        renderOrder: lineFeaturesOrder,
-        style: stopStyle,
-        imageRatio: 2,
-        minZoom: 13,
-    });
+            props.innerSize = SEGMENT_SIZE / count;
+            props.innerColor = network.lines[line].color;
+            props.innerOffset = getOffset(SEGMENT_SIZE, index, count);
 
-    return [segmentsBorderLayer, segmentsInnerLayer, stopsLayer];
+            props.outerSize = (SEGMENT_SIZE + BORDER_SIZE) / count;
+            props.outerColor = makeBorderColor(props.innerColor);
+            props.outerOffset = getOffset(SEGMENT_SIZE + BORDER_SIZE, index, count);
+
+            segments.push(feature);
+        }
+    }
+
+    return turfHelpers.featureCollection(segments);
+};
+
+/** Get the collection of stops. */
+const getStops = () => {
+    const stops = [];
+
+    for (const stop of Object.values(network.stops)) {
+        const lines = [...new Set(
+            stop.properties.routes.map(([lineRef]) => lineRef)
+        )];
+        lines.sort();
+        const count = lines.length;
+
+        // Duplicate and offset stops for each route
+        for (const [index, line] of lines.entries()) {
+            const feature = turfClone(stop);
+            const props = feature.properties;
+            props.line = line;
+
+            props.innerSize = (count - index) * STOP_SIZE / 2 / count;
+            props.innerColor = network.lines[line].color;
+
+            if (index === 0) {
+                props.outerSize = (STOP_SIZE + BORDER_SIZE) / 2;
+            } else {
+                props.outerSize = 0;
+            }
+
+            props.outerColor = makeBorderColor(props.innerColor);
+            stops.push(feature);
+        }
+    }
+
+    return turfHelpers.featureCollection(stops);
+};
+
+/**
+ * Add layers that display the transit network on the map.
+ * @param {Map} map The map to add the layers to.
+ */
+export const addLayers = map => {
+    map.addSource("lines", {
+        type: "geojson",
+        data: getSegments(),
+    });
+
+    map.addSource("stops", {
+        type: "geojson",
+        data: getStops(),
+    });
+
+    for (const lineRef of Object.keys(network.lines)) {
+        for (const kind of ["outer", "inner"]) {
+            map.addLayer({
+                id: `line-${lineRef}-${kind}`,
+                type: "line",
+                source: "lines",
+                filter: ["==", "line", lineRef],
+                minzoom: MIN_ZOOM_SEGMENTS,
+                layout: {
+                    "line-cap": "round",
+                    "line-join": "round",
+                },
+                paint: {
+                    "line-color": ["get", `${kind}Color`],
+                    "line-width": scaleZoom(["get", `${kind}Size`]),
+                    "line-offset": scaleZoom(["get", `${kind}Offset`]),
+                },
+            });
+        }
+    }
+
+    for (const lineRef of Object.keys(network.lines)) {
+        for (const kind of ["outer", "inner"]) {
+            map.addLayer({
+                id: `stops-${lineRef}-${kind}`,
+                type: "circle",
+                source: "stops",
+                filter: ["==", "line", lineRef],
+                minzoom: MIN_ZOOM_STOPS,
+                paint: {
+                    "circle-pitch-alignment": "map",
+                    "circle-color": ["get", `${kind}Color`],
+                    "circle-radius": scaleZoom(["get", `${kind}Size`]),
+                },
+            });
+        }
+    }
 };

src/front/map/tiles.js

@@ -1,23 +0,0 @@
-import TileLayer from "ol/layer/Tile";
-import XYZSource from "ol/source/XYZ";
-
-const mapboxToken = "pk.eyJ1IjoibWF0dGVvZGVsYWJyZSIsImEiOiJja2NxaTUyMmUwcmFhMn\
-h0NmFsdzQ3emxqIn0.cyxF0h36emIMTk3cc4VqUw";
-
-/**
- * Create the list of layers for displaying the background map.
- * @returns {Array.<Layer>} List of map layers.
- */
-export const getLayers = () => {
-    const backgroundSource = new XYZSource({
-        url: `https://api.mapbox.com/${[
-            "styles", "v1", "mapbox", "streets-v11",
-            "tiles", "512", "{z}", "{x}", "{y}"
-        ].join("/")}?access_token=${mapboxToken}`,
-        tileSize: [512, 512]
-    });
-
-    return [new TileLayer({
-        source: backgroundSource
-    })];
-};

src/front/map/vehicles.js

@@ -0,0 +1,233 @@
+// import { getVectorContext } from "ol/render";
+// import Point from "ol/geom/Point";
+// import { fromExtent } from 'ol/geom/Polygon';
+// import { Style, Icon } from "ol/style";
+import * as turfHelpers from "@turf/helpers";
+
+import { scaleZoom, makeBorderColor, makeCourseColor } from "./common";
+import network from "../../data/network.json";
+
+const VEHICLE_SIZE = 15;
+const VEHICLE_BORDER = 10;
+
+const makeVehicleIcon = size => {
+    const canvas = window.document.createElement("canvas");
+    const context = canvas.getContext("2d");
+
+    canvas.width = size;
+    canvas.height = size;
+
+    const cx = size / 2;
+    const cy = size / 2;
+
+    const iconSize = 0.4 * size;
+    const borderSize = 0.2 * size;
+
+    context.fillStyle = "black";
+    context.strokeStyle = "black";
+    context.lineWidth = borderSize;
+    context.lineJoin = "round";
+    context.miterLimit = 200000;
+
+    context.beginPath();
+    context.moveTo(cx - 0.3 * iconSize, cy + 0.5 * iconSize);
+    context.lineTo(cx, cy - 0.5 * iconSize);
+    context.lineTo(cx + 0.3 * iconSize, cy + 0.5 * iconSize);
+    context.closePath();
+    context.stroke();
+    context.fill();
+
+    return {
+        width: size,
+        height: size,
+        data: context.getImageData(0, 0, size, size).data,
+    };
+};
+
+/**
+ * Add layers that display the live vehicle positions on the map.
+ * @param {Map} map The map to add the layers to.
+ */
+export const addLayers = map => {
+    map.addImage("vehicle", makeVehicleIcon(128), {sdf: true});
+
+    map.addSource("vehicles", {
+        type: "geojson",
+        data: turfHelpers.featureCollection([]),
+    });
+
+    for (let [kind, factor] of [
+        ["outer", 0.3],
+        ["border", 0.25],
+        ["inner", 0.2],
+    ]) {
+        map.addLayer({
+            id: `vehicles-${kind}`,
+            type: "symbol",
+            source: "vehicles",
+            layout: {
+                "icon-image": "vehicle",
+                "icon-size": scaleZoom(factor),
+                "icon-allow-overlap": true,
+                "icon-rotation-alignment": "map",
+                "icon-rotate": ["get", "bearing"],
+            },
+            paint: {
+                "icon-color": ["get", `${kind}Color`],
+            },
+        });
+    }
+};
+
+/**
+ * Update the vehicle positions on the map.
+ * @param {Map} map The map to update.
+ * @param {Array<Object>} courses The active courses.
+ */
+export const update = (map, courses) => {
+    const features = Object.values(courses);
+
+    for (let course of features) {
+        const props = course.properties;
+        props.borderColor = network.lines[props.line].color;
+        props.innerColor = makeCourseColor(props.borderColor);
+        props.outerColor = makeBorderColor(props.borderColor);
+    }
+
+    map.getSource("vehicles").setData(
+        turfHelpers.featureCollection(Object.values(courses))
+    );
+};
+
+// const courseStyle = cacheStyle(
+//     lineColor => {
+//         const icon = window.document.createElement("canvas");
+
+//         const shapeSize = sizes.courseSize;
+//         const iconSize = sizes.courseSize + sizes.courseOuterBorder;
+
+//         icon.width = iconSize;
+//         icon.height = iconSize;
+
+//         const cx = icon.width / 2;
+//         const cy = icon.height / 2;
+
+//         const iconCtx = icon.getContext("2d");
+
+//         for (const [color, size] of [
+//             [makeBorderColor(lineColor), sizes.courseOuterBorder],
+//             [lineColor, sizes.courseBorder],
+//             [makeCourseColor(lineColor), sizes.courseInnerBorder]
+//         ]) {
+//             iconCtx.fillStyle = color;
+//             iconCtx.strokeStyle = color;
+//             iconCtx.lineWidth = size;
+//             iconCtx.lineJoin = "round";
+//             iconCtx.miterLimit = 200000;
+
+//             iconCtx.beginPath();
+//             iconCtx.moveTo(cx - 0.5 * shapeSize, cy - 0.3 * shapeSize);
+//             iconCtx.lineTo(cx + 0.5 * shapeSize, cy);
+//             iconCtx.lineTo(cx - 0.5 * shapeSize, cy + 0.3 * shapeSize);
+//             iconCtx.closePath();
+//             iconCtx.stroke();
+//             iconCtx.fill();
+//         }
+
+//         return new Style({
+//             image: new Icon({
+//                 img: icon,
+//                 imgSize: [icon.width, icon.height]
+//             })
+//         });
+//     },
+// );
+
+// export const setupCoursesAnimation = (
+//     map, coursesSimulation, stopsLayer, onClick
+// ) => {
+//     const view = map.getView();
+
+//     // Draw courses directly on the map
+//     map.on("postcompose", ev => {
+//         coursesSimulation.update();
+
+//         // The normal way to access a layer’s vector context is through the
+//         // `postrender` event of that layer. However, `postrender` is not
+//         // triggered when no feature of the layer is inside the current
+//         // bounding box, but we want to draw vehicles in between stops even
+//         // if no stop is visible. This hack listens to the global `postcompose`
+//         // event, which is always triggered at every frame, and reconstructs
+//         // the stops layer’s vector context from internal variables
+//         /* eslint-disable no-underscore-dangle */
+//         if (stopsLayer.renderer_) {
+//             ev.context = stopsLayer.renderer_.context;
+//             ev.inversePixelTransform =
+//                 stopsLayer.renderer_.inversePixelTransform;
+//             /* eslint-enable no-underscore-dangle */
+
+//             const ctx = getVectorContext(ev);
+//             const bbox = fromExtent(map.getView().calculateExtent());
+//             bbox.scale(1.05);
+
+//             for (const course of Object.values(coursesSimulation.courses)) {
+//                 if (!bbox.intersectsCoordinate(course.position)) {
+//                     continue;
+//                 }
+
+//                 const point = new Point(course.position);
+//                 const color = network.lines[course.line].color;
+//                 const style = courseStyle(color);
+
+//                 style.getImage().setRotation(
+//                     view.getRotation() +
+//                     course.angle
+//                 );
+
+//                 ctx.setStyle(style);
+//                 ctx.drawGeometry(point);
+//             }
+//         }
+
+//         map.render();
+//     });
+
+//     map.on("singleclick", ev => {
+//         const mousePixel = map.getPixelFromCoordinate(ev.coordinate);
+//         const maxDistance = sizes.courseSize + sizes.courseInnerBorder;
+//         const clicked = [];
+
+//         for (const course of Object.values(coursesSimulation.courses)) {
+//             const coursePixel = map.getPixelFromCoordinate(course.position);
+//             const dx = mousePixel[0] - coursePixel[0];
+//             const dy = mousePixel[1] - coursePixel[1];
+//             const distance = dx * dx + dy * dy;
+
+//             if (distance <= maxDistance * maxDistance) {
+//                 clicked.push(course.id);
+//             }
+//         }
+
+//         // Sort selected courses in increasing departing/arrival time
+//         clicked.sort((id1, id2) => {
+//             const course1 = coursesSimulation.courses[id1];
+//             const course2 = coursesSimulation.courses[id2];
+
+//             const time1 = (
+//                 course1.state === "moving"
+//                 ? course1.arrivalTime
+//                 : course1.departureTime
+//             );
+
+//             const time2 = (
+//                 course2.state === "moving"
+//                 ? course2.arrivalTime
+//                 : course2.departureTime
+//             );
+
+//             return time1 - time2;
+//         });
+
+//         onClick(clicked);
+//     });
+// };