feat: add shared MapLibre GL utilities (journey line, markers)

themes/intotheeast/js/maplibre-utils.js

@@ -0,0 +1,109 @@
+/* Shared MapLibre GL utilities — loaded by map.html.twig, dailies.html.twig, home.html.twig */
+(function (global) {
+  var ACCENT      = '#2A8C73';
+  var ACCENT_DIM  = '#155244';
+  var MAP_STYLE   = 'https://basemaps.cartocdn.com/gl/dark-matter-gl-style/style.json';
+
+  /* Build a GeoJSON LineString feature */
+  function lineFeature(coords) {
+    return { type: 'Feature', properties: {}, geometry: { type: 'LineString', coordinates: coords } };
+  }
+
+  /*
+   * Progressively draw the journey line using a requestAnimationFrame loop.
+   * coords: [[lng, lat], ...] in chronological order.
+   * sourceId: the MapLibre source id to update each frame.
+   */
+  function animateJourneyLine(map, coords, sourceId) {
+    if (coords.length < 2) return;
+
+    /* Cumulative Euclidean distance between waypoints */
+    var segDist = [0];
+    for (var i = 1; i < coords.length; i++) {
+      var dx = coords[i][0] - coords[i - 1][0];
+      var dy = coords[i][1] - coords[i - 1][1];
+      segDist.push(segDist[i - 1] + Math.sqrt(dx * dx + dy * dy));
+    }
+    var totalDist = segDist[segDist.length - 1];
+    var DURATION  = 5000;
+    var startTime = performance.now();
+
+    function frame(now) {
+      if (!map.getSource(sourceId)) return; /* map was removed */
+      var t      = Math.min((now - startTime) / DURATION, 1);
+      var eased  = 1 - Math.pow(1 - t, 3); /* ease-out cubic */
+      var target = eased * totalDist;
+
+      var animCoords = [coords[0]];
+      for (var j = 1; j < coords.length; j++) {
+        if (segDist[j] <= target) {
+          animCoords.push(coords[j]);
+        } else {
+          var frac = (target - segDist[j - 1]) / (segDist[j] - segDist[j - 1]);
+          animCoords.push([
+            coords[j - 1][0] + (coords[j][0] - coords[j - 1][0]) * frac,
+            coords[j - 1][1] + (coords[j][1] - coords[j - 1][1]) * frac
+          ]);
+          break;
+        }
+      }
+
+      map.getSource(sourceId).setData(lineFeature(animCoords));
+      if (t < 1) requestAnimationFrame(frame);
+    }
+
+    requestAnimationFrame(frame);
+  }
+
+  /*
+   * Add a journey line source + two layers (glow + main) to a loaded map,
+   * then animate or draw instantly based on prefers-reduced-motion.
+   */
+  function addJourneyLine(map, coords, sourceId) {
+    if (coords.length < 2) return;
+
+    map.addSource(sourceId, { type: 'geojson', data: lineFeature([coords[0]]) });
+
+    map.addLayer({
+      id: sourceId + '-glow', type: 'line', source: sourceId,
+      layout: { 'line-join': 'round', 'line-cap': 'round' },
+      paint:  { 'line-color': ACCENT, 'line-width': 6, 'line-opacity': 0.18 }
+    });
+
+    map.addLayer({
+      id: sourceId + '-line', type: 'line', source: sourceId,
+      layout: { 'line-join': 'round', 'line-cap': 'round' },
+      paint:  { 'line-color': ACCENT, 'line-width': 2.5, 'line-opacity': 0.85 }
+    });
+
+    var reducedMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
+    if (reducedMotion) {
+      map.getSource(sourceId).setData(lineFeature(coords));
+    } else {
+      animateJourneyLine(map, coords, sourceId);
+    }
+  }
+
+  /*
+   * Return a styled <div> element for a map marker dot.
+   * isLatest: make it larger with a teal ring.
+   */
+  function createDotMarker(isLatest) {
+    var el   = document.createElement('div');
+    var size = isLatest ? 18 : 12;
+    var bg   = isLatest ? ACCENT_DIM : ACCENT;
+    var ring = isLatest ? ',0 0 0 4px rgba(42,140,115,0.25)' : '';
+    el.style.cssText = [
+      'width:' + size + 'px',
+      'height:' + size + 'px',
+      'background:' + bg,
+      'border:2px solid #fff',
+      'border-radius:50%',
+      'box-shadow:0 1px 4px rgba(0,0,0,0.4)' + ring,
+      'cursor:pointer'
+    ].join(';');
+    return el;
+  }
+
+  global.MapUtils = { MAP_STYLE: MAP_STYLE, ACCENT: ACCENT, addJourneyLine: addJourneyLine, createDotMarker: createDotMarker };
+})(window);