Add GPX trail maps to blog posts

This adds a trail flow block so posts can include attached GPX files as
interactive maps with route display, elevation charts, activity
summaries, and start/finish markers.

The trail assets are loaded only when needed, keeping the shared
templates clean while vendoring the Leaflet dependencies required for
offline, self-hosted map rendering.

1 files changed, 347 insertions, 0 deletions

diff --git a/assets/static/vendor/leaflet-elevation/libs/leaflet-gpxgroup.js b/assets/static/vendor/leaflet-elevation/libs/leaflet-gpxgroup.js
new file mode 100644
index 0000000..c7a9dd6
--- /dev/null
+++ b/assets/static/vendor/leaflet-elevation/libs/leaflet-gpxgroup.js
@@ -0,0 +1,347 @@
+/*
+ * https://github.com/adoroszlai/joebed/tree/gh-pages
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014- Doroszlai Attila, 2019- Raruto
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+L.Mixin.Selectable = {
+  includes: L.Mixin.Events,
+
+  setSelected: function(s) {
+    var selected = !!s;
+    if (this._selected !== selected) {
+      this._selected = selected;
+      this.fire('selected');
+    }
+  },
+
+  isSelected: function() {
+    return !!this._selected;
+  },
+};
+
+L.Mixin.Selection = {
+  includes: L.Mixin.Events,
+
+  getSelection: function() {
+    return this._selected;
+  },
+
+  setSelection: function(item) {
+    if (this._selected === item) {
+      if (item !== null) {
+        item.setSelected(!item.isSelected());
+        if (!item.isSelected()) {
+          this._selected = null;
+        }
+      }
+    } else {
+      if (this._selected) {
+        this._selected.setSelected(false);
+      }
+      this._selected = item;
+      if (this._selected) {
+        this._selected.setSelected(true);
+      }
+    }
+    this.fire('selection_changed');
+  },
+};
+
+L.Control.LayersLegend = L.Control.Layers.extend({
+  _onInputClick: function() {
+    this._handlingClick = true;
+
+    this._layerControlInputs.reduceRight((_,input) => {
+      if (input.checked) {
+        this._map.fireEvent("legend_selected", {
+          layer: this._getLayer(input.layerId).layer,
+          input: input,
+        }, true);
+      return input;
+     }
+    }, 0);
+
+    this._handlingClick = false;
+
+    this._refocusOnMap();
+  }
+});
+
+L.control.layersLegend = (baseLayers, overlays, options) => new L.Control.LayersLegend(baseLayers, overlays, options);
+
+L.GeoJSON.include(L.Mixin.Selectable);
+
+L.GpxGroup = L.Class.extend({
+  options: {
+    highlight: {
+      color: '#ff0',
+      opacity: 1,
+    },
+    points: [],
+    points_options: {
+      icon: {
+        iconUrl: '../images/elevation-poi.png',
+        iconSize: [12, 12],
+      }
+    },
+    flyToBounds: true,
+    legend: false,
+    legend_options: {
+      position: "topright",
+      collapsed: false,
+    },
+    elevation: true,
+    elevation_options: {
+      theme: 'yellow-theme',
+      detached: true,
+      elevationDiv: '#elevation-div',
+    },
+    distanceMarkers: true,
+    distanceMarkers_options: {
+      lazy: true
+    },
+  },
+
+  initialize: function(tracks, options) {
+
+    L.Util.setOptions(this, options);
+
+    this._count       = 0;
+    this._loadedCount = 0;
+    this._tracks      = tracks;
+    this._layers      = L.featureGroup();
+    this._markers     = L.featureGroup();
+    this._elevation   = L.control.elevation(this.options.elevation_options);
+    this._legend      = L.control.layersLegend(null, null, this.options.legend_options);
+
+    this.options.points.forEach((poi) => 
+      L
+        .marker(poi.latlng, { icon: L.icon(this.options.points_options.icon) })
+        .bindTooltip(poi.name, { direction: 'auto' }).addTo(this._markers)
+    );
+
+  },
+
+  getBounds: function() {
+    return this._layers.getBounds();
+  },
+
+  addTo: function(map) {
+    this._layers.addTo(map);
+    this._markers.addTo(map);
+
+    this._map = map;
+
+    this.on('selection_changed', this._onSelectionChanged, this);
+    this._map.on('legend_selected', this._onLegendSelected, this);
+    this._tracks.forEach(this.addTrack, this);
+
+  },
+
+  addTrack: function(track) {
+    if (track instanceof Object) {
+      this._loadGeoJSON(track);
+    } else {
+      fetch(track)
+        .then(response => response.ok && response.text())
+        .then(text => this._elevation._parseFromString(text))
+        .then(geojson => this._loadGeoJSON(geojson, track.split('/').pop().split('#')[0].split('?')[0]));
+    }
+  },
+
+  _loadGeoJSON: function(geojson, fallbackName) {
+    if (geojson) {
+      geojson.name = geojson.name || (geojson[0] && geojson[0].properties.name) || fallbackName;
+      this._loadRoute(geojson);
+    }
+  },
+
+  _loadRoute: function(data) {
+    if (!data) return;
+
+    var line_style = {
+      color: this._uniqueColors(this._tracks.length)[this._count++],
+      opacity: 0.75,
+      weight: 5,
+      distanceMarkers: this.options.distanceMarkers_options,
+    };
+
+    var route = L.geoJson(data, {
+      name: data.name || '',
+      style: (feature) => line_style,
+      distanceMarkers: line_style.distanceMarkers,
+      originalStyle: line_style,
+      filter: feature => feature.geometry.type != "Point",
+    });
+
+    
+    this._elevation.import(this._elevation.__LGEOMUTIL).then(() => {
+      route.addTo(this._layers);
+
+      route.eachLayer((layer) => this._onEachRouteLayer(route, layer));
+      this._onEachRouteLoaded(route);
+    });
+
+  },
+
+  _onEachRouteLayer: function(route, layer) {
+    var polyline = layer;
+
+    route.on('selected', L.bind(this._onRouteSelected, this, route, polyline));
+
+    polyline.on('mouseover', L.bind(this._onRouteMouseOver, this, route, polyline));
+    polyline.on('mouseout', L.bind(this._onRouteMouseOut, this, route, polyline));
+    polyline.on('click', L.bind(this._onRouteClick, this, route, polyline));
+
+    polyline.bindTooltip(route.options.name, { direction: 'auto', sticky: true, });
+  },
+
+  _onEachRouteLoaded: function(route) {
+    if (this.options.legend) {
+      this._legend.addBaseLayer(route, '<svg id="legend_' + route._leaflet_id + '" width="25" height="10" version="1.1" xmlns="http://www.w3.org/2000/svg">' + '<line x1="0" x2="50" y1="5" y2="5" stroke="' + route.options.originalStyle.color + '" fill="transparent" stroke-width="5" /></svg>' + ' ' + route.options.name);
+    }
+    
+    this.fire('route_loaded', { route: route });
+
+    if (++this._loadedCount === this._tracks.length) {
+      this.fire('loaded');
+      if (this.options.flyToBounds) {
+        this._map.flyToBounds(this.getBounds(), { duration: 0.25, easeLinearity: 0.25, noMoveStart: true });
+      }
+      if (this.options.legend) {
+        this._legend.addTo(this._map);
+      }
+    }
+  },
+
+  highlight: function(route, polyline) {
+    polyline.setStyle(this.options.highlight);
+    if (this.options.distanceMarkers) {
+      polyline.addDistanceMarkers();
+    }
+  },
+
+  unhighlight: function(route, polyline) {
+    polyline.setStyle(route.options.originalStyle);
+    if (this.options.distanceMarkers) {
+      polyline.removeDistanceMarkers();
+    }
+  },
+
+  _onRouteMouseOver: function(route, polyline) {
+    if (!route.isSelected()) {
+      this.highlight(route, polyline);
+      if (this.options.legend) {
+        this.setSelection(route);
+        L.DomUtil.get('legend_' + route._leaflet_id).parentNode.previousSibling.click();
+      }
+    }
+    this.fire('route_mouseover', { route: route, polyline: polyline });
+  },
+
+  _onRouteMouseOut: function(route, polyline) {
+    if (!route.isSelected()) {
+      this.unhighlight(route, polyline);
+    }
+    this.fire('route_mouseout', { route: route, polyline: polyline });
+  },
+
+  _onRouteClick: function(route, polyline) {
+    this.setSelection(route);
+  },
+
+  _onRouteSelected: function(route, polyline) {
+    if (!route.isSelected()) {
+      this.unhighlight(route, polyline);
+    }
+  },
+
+  _onSelectionChanged: function(e) {
+    var elevation = this._elevation;
+    var eleDiv = elevation.getContainer();
+    var route = this.getSelection();
+
+    elevation.clear();
+
+    if (route && route.isSelected()) {
+      if (!eleDiv) {
+        elevation.addTo(this._map);
+      }
+      route.getLayers().forEach(function(layer) {
+        if (layer instanceof L.Polyline) {
+          elevation.addData(layer, false);
+          layer.bringToFront();
+        }
+      });
+    } else {
+      if (eleDiv) {
+        elevation.remove();
+      }
+    }
+  },
+
+  _onLegendSelected: function(e) {
+    var parent = e.input.closest('.leaflet-control-layers-list');
+    var route = e.layer;
+
+    if (!route.isSelected()) {
+      this.setSelection(route);
+      for (var i in route._layers) {
+        this.highlight(route, route._layers[i]);
+      }
+      this._map.flyToBounds(e.layer.getBounds());
+    }
+
+    parent.scroll({ top: (e.input.offsetTop - parent.offsetTop) || 0, behavior: 'smooth' });
+
+    this._layers.eachLayer(layer => {
+      var legend = L.DomUtil.get('legend_' + layer._leaflet_id);
+      legend.querySelector("line").style.stroke = layer.isSelected() ? this.options.highlight.color : "";
+      legend.parentNode.style.fontWeight = layer.isSelected() ? "700" : "";
+    });
+  },
+
+  _uniqueColors: function(count) {
+    return count === 1 ? ['#0000ff'] : new Array(count).fill(null).map((_,i) => this._hsvToHex(i * (1 / count), 1, 0.7));
+  },
+
+  _hsvToHex: function(h, s, v) {
+    var i = Math.floor(h * 6);
+    var f = h * 6 - i;
+    var p = v * (1 - s);
+    var q = v * (1 - f * s);
+    var t = v * (1 - (1 - f) * s);
+    var rgb = { 0: [v, t, p], 1: [q, v, p], 2: [p, v, t], 3: [p, q, v], 4: [t, p, v], 5: [v, p, q] }[i % 6];
+    return rgb.map(d => d * 255).reduce((hex, byte) => hex + ((byte >> 4) & 0x0F).toString(16) + (byte & 0x0F).toString(16), "#");
+  },
+
+  removeFrom: function(map) {
+    this._layers.removeFrom(map);
+  },
+
+});
+
+L.GpxGroup.include(L.Mixin.Events);
+L.GpxGroup.include(L.Mixin.Selection);
+
+L.gpxGroup = (tracks, options) => new L.GpxGroup(tracks, options);
\ No newline at end of file