SGH / COMPONENTS

  <!-- Copyright (c) 2015 Google Inc. All rights reserved. -->
  
  <link rel="import" href="../polymer/polymer.html">
  <link rel="import" href="../google-apis/google-maps-api.html">
  <link rel="import" href="google-map-point.html">
  
  <!--
  The `google-map-poly` element represents a series of connected line segments (aka a polyline) which
  may also be closed to form a polygon (provided there are at least three points). It is used as a
  child of `google-map` and will contain at least two `google-map-point` child elements.
  
  <b>Example</b>—a simple line:
  
      <google-map latitude="37.77493" longitude="-122.41942">
        <google-map-poly>
          <google-map-point latitude="37.77493" longitude="-122.41942"></google-map-point>
          <google-map-point latitude="38.77493" longitude="-123.41942"></google-map-point>
        </google-map-poly>
      </google-map>
  
  <b>Example</b>—a semi-translucent blue triangle:
  
      <google-map latitude="37.77493" longitude="-122.41942">
        <google-map-poly closed fill-color="blue" fill-opacity=".5">
          <google-map-point latitude="36.77493" longitude="-121.41942"></google-map-point>
          <google-map-point latitude="38.77493" longitude="-122.41942"></google-map-point>
          <google-map-point latitude="36.77493" longitude="-123.41942"></google-map-point>
        </google-map-poly>
      </google-map>
  -->
  
  <dom-module id="google-map-poly">
    <style>
      :host {
        display: none;
      }
    </style>
    <template>
      <content id="points" select="google-map-point"></content>
    </template>
  </polymer-element>
  
  <script>
    Polymer({
      is: 'google-map-poly',
  
      /**
       * Fired when the `path` property is built based on child `google-map-point` elements, either
       * initially or when they are changed.
       * @event google-map-poly-path-built
       * @param {MVCArray.<LatLng>} path The poly path.
       */
      /**
       * Fired when the user finishes adding vertices to the poly. The host component can use the
       * provided path to rebuild its list of points.
       * @event google-map-poly-path-updated
       * @param {MVCArray.<LatLng>} path The poly path.
       */
      /**
       * Fired when the DOM `click` event is fired on the poly. Requires the clickEvents attribute to
       * be true.
       * @event google-map-poly-click
       * @param {google.maps.PolyMouseEvent} event The poly event.
       */
      /**
       * Fired when the DOM `dblclick` event is fired on the poly. Requires the clickEvents attribute
       * to be true.
       * @event google-map-poly-dblclick
       * @param {google.maps.PolyMouseEvent} event The poly event.
       */
      /**
       * Fired repeatedly while the user drags the poly. Requires the dragEvents attribute to be true.
       * @event google-map-poly-drag
       * @param {google.maps.MouseEvent} event The mouse event.
       */
      /**
       * Fired when the user stops dragging the poly. Requires the dragEvents attribute to be true.
       * @event google-map-poly-dragend
       * @param {google.maps.MouseEvent} event The mouse event.
       */
      /**
       * Fired when the user starts dragging the poly. Requires the dragEvents attribute to be true.
       * @event google-map-poly-dragstart
       * @param {google.maps.MouseEvent} event The mouse event.
       */
      /**
       * Fired when the DOM `mousedown` event is fired on the poly. Requires the mouseEvents attribute
       * to be true.
       * @event google-map-poly-mousedown
       * @param {google.maps.PolyMouseEvent} event The poly event.
       */
      /**
       * Fired when the DOM `mousemove` event is fired on the poly. Requires the mouseEvents attribute
       * to be true.
       * @event google-map-poly-mousemove
       * @param {google.maps.PolyMouseEvent} event The poly event.
       */
      /**
       * Fired on poly mouseout. Requires the mouseEvents attribute to be true.
       * @event google-map-poly-mouseout
       * @param {google.maps.PolyMouseEvent} event The poly event.
       */
      /**
       * Fired on poly mouseover. Requires the mouseEvents attribute to be true.
       * @event google-map-poly-mouseover
       * @param {google.maps.PolyMouseEvent} event The poly event.
       */
      /**
       * Fired when the DOM `mouseup` event is fired on the poly. Requires the mouseEvents attribute
       * to be true.
       * @event google-map-poly-mouseup
       * @param {google.maps.PolyMouseEvent} event The poly event.
       */
      /**
       * Fired when the poly is right-clicked on. Requires the clickEvents attribute to be true.
       * @event google-map-poly-rightclick
       * @param {google.maps.PolyMouseEvent} event The poly event.
       */
      properties: {
        /**
         * A Google Maps polyline or polygon object (depending on value of "closed" attribute).
         * @type google.maps.Polyline|google.maps.Polygon
         */
        poly: {
          type: Object,
          readOnly: true
        },
  
        /**
         * An array of the Google Maps LatLng objects that define the poly shape.
         * @type MVCArray.<LatLng>
         */
        path: {
          type: Object,
          readOnly: true
        },
  
        /**
         * The Google map object.
         * @type google.maps.Map
         */
        map: {
          type: Object,
          observer: '_mapChanged'
        },
  
        /**
         * When true, the poly will generate mouse events.
         */
        clickable: {
          type: Boolean,
          value: false,
          observer: '_clickableChanged'
        },
  
        /**
         * When true, the google-map-poly-*click events will be automatically registered.
         */
         clickEvents: {
           type: Boolean,
           value: false,
           observer: '_clickEventsChanged'
         },
  
        /**
         * When true, the path will be closed by connecting the last point to the first one and
         * treating the poly as a polygon.
         */
        closed: {
          type: Boolean,
          value: false,
          observer: '_closedChanged'
        },
  
        /**
         * When true, the poly may be dragged to a new position.
         */
        draggable: {
          type: Boolean,
          value: false,
        },
  
        /**
         * When true, the google-map-poly-drag* events will be automatically registered.
         */
        dragEvents: {
          type: Boolean,
          value: false,
          observer: '_dragEventsChanged'
        },
  
        /**
         * When true, the poly's vertices may be individually moved or new ones added.
         */
        editable: {
          type: Boolean,
          value: false,
          observer: '_editableChanged'
        },
  
        /**
         * When true, indicates that the user has begun editing the poly path (adding vertices).
         */
        editing: {
          type: Boolean,
          value: false,
          notify: true,
          readOnly: true
        },
  
        /**
         * If the path is closed, the polygon fill color. All CSS3 colors are supported except for
         * extended named colors.
         */
        fillColor: {
          type: String,
          value: '',
          observer: '_fillColorChanged'
        },
  
        /**
         * If the path is closed, the polygon fill opacity (between 0.0 and 1.0).
         */
        fillOpacity: {
          type: Number,
          value: 0,
          observer: '_fillOpacityChanged'
        },
  
        /**
         * When true, the poly's edges are interpreted as geodesic and will follow the curvature of
         * the Earth. When not set, the poly's edges are rendered as straight lines in screen space.
         * Note that the poly of a geodesic poly may appear to change when dragged, as the dimensions
         * are maintained relative to the surface of the earth.
         */
        geodesic: {
          type: Boolean,
          value: false,
          observer: '_geodesicChanged'
        },
  
        /**
         * If the path is not closed, the icons to be rendered along the polyline.
         */
        icons: {
          type: Array,
          value: null,
          observer: '_iconsChanged'
        },
  
        /**
         * When true, the google-map-poly-mouse* events will be automatically registered.
         */
         mouseEvents: {
           type: Boolean,
           value: false,
           observer: '_mouseEventsChanged'
         },
  
        /**
         * The color to draw the poly's stroke with. All CSS3 colors are supported except for extended
         * named colors.
         */
        strokeColor: {
          type: String,
          value: 'black',
          observer: '_strokeColorChanged'
        },
  
        /**
         * The stroke opacity (between 0.0 and 1.0).
         */
        strokeOpacity: {
          type: Number,
          value: 1,
          observer: '_strokeOpacityChanged'
        },
  
        /**
         * The stroke position (center, inside, or outside).
         */
        strokePosition: {
          type: String,
          value: 'center',
          observer: '_strokePositionChanged'
        },
  
        /**
         * The stroke width in pixels.
         */
        strokeWeight: {
          type: Number,
          value: 3,
          observer: '_strokeWeightChanged'
        },
  
        /**
         * The Z-index relative to other objects on the map.
         */
        zIndex: {
          type: Number,
          value: 0,
          observer: '_zIndexChanged'
        }
      },
  
      // Lifecycle event handlers.
  
      detached: function() {
        this.poly.setMap(null);
        if (this._pointsObserver) {
          this._pointsObserver.disconnect();
          this._pointsObserver = null;
        }
        for (var name in this._listeners) {
          this._clearListener(name);
        }
      },
  
      attached: function() {
        // If element is added back to DOM, put it back on the map.
        this.poly && this.poly.setMap(this.map);
      },
  
      // Attribute/property change watchers.
  
      attributeChanged: function(attrName, oldVal, newVal) {
        if (!this.poly) {
          return;
        }
  
        // Cannot use *Changed watchers for native properties.
        switch (attrName) {
          case 'hidden':
            this.poly.setVisible(!this.hidden);
            break;
          case 'draggable':
            this.poly.setDraggable(this.draggable);
            break;
        }
      },
  
      _clickableChanged: function() {
        this.poly && this.poly.set('clickable', this.clickable);
      },
  
      _clickEventsChanged: function() {
        if (this.poly) {
          if (this.clickEvents) {
            this._forwardEvent('click');
            this._forwardEvent('dblclick');
            this._forwardEvent('rightclick');
          } else {
            this._clearListener('click');
            this._clearListener('dblclick');
            this._clearListener('rightclick');
          }
        }
      },
  
      _closedChanged: function() {
        this._mapChanged();
      },
  
      _dragEventsChanged: function() {
        if (this.poly) {
          if (this.clickEvents) {
            this._forwardEvent('drag');
            this._forwardEvent('dragend');
            this._forwardEvent('dragstart');
          } else {
            this._clearListener('drag');
            this._clearListener('dragend');
            this._clearListener('dragstart');
          }
        }
      },
  
      _editableChanged: function() {
        this.poly && this.poly.setEditable(this.editable);
      },
  
      _fillColorChanged: function() {
        this.poly && this.poly.set('fillColor', this.fillColor);
      },
  
      _fillOpacityChanged: function() {
        this.poly && this.poly.set('fillOpacity', this.fillOpacity);
      },
  
      _geodesicChanged: function() {
        this.poly && this.poly.set('geodesic', this.geodesic);
      },
  
      _iconsChanged: function() {
        this.poly && this.poly.set('icons', this.icons);
      },
  
      _mapChanged: function() {
        // Poly will be rebuilt, so disconnect existing one from old map and listeners.
        if (this.poly) {
          this.poly.setMap(null);
          google.maps.event.clearInstanceListeners(this.poly);
        }
  
        if (this.map && this.map instanceof google.maps.Map) {
          this._createPoly();
        }
      },
  
      _mouseEventsChanged: function() {
        if (this.poly) {
          if (this.mouseEvents) {
            this._forwardEvent('mousedown');
            this._forwardEvent('mousemove');
            this._forwardEvent('mouseout');
            this._forwardEvent('mouseover');
            this._forwardEvent('mouseup');
          } else {
            this._clearListener('mousedown');
            this._clearListener('mousemove');
            this._clearListener('mouseout');
            this._clearListener('mouseover');
            this._clearListener('mouseup');
          }
        }
      },
  
      _strokeColorChanged: function() {
        this.poly && this.poly.set('strokeColor', this.strokeColor);
      },
  
      _strokeOpacityChanged: function() {
        this.poly && this.poly.set('strokeOpacity', this.strokeOpacity);
      },
  
      _strokePositionChanged: function() {
        this.poly && this.poly.set('strokePosition', this._convertStrokePosition());
      },
  
      _strokeWeightChanged: function() {
        this.poly && this.poly.set('strokeWeight', this.strokeWeight);
      },
  
      _zIndexChanged: function() {
        this.poly && this.poly.set('zIndex', this.zIndex);
      },
  
      // Helper logic.
  
      _buildPathFromPoints: function() {
        this._points = Array.prototype.slice.call(Polymer.dom(this.$.points).getDistributedNodes());
  
        // Build path from current points (ignoring vertex insertions while doing so).
        this._building = true;
        this.path.clear();
        for (var i = 0, point; point = this._points[i]; ++i) {
          this.path.push(point.getPosition());
        }
        this._building = false;
  
        this.fire('google-map-poly-path-built', this.path);
  
        // Watch for future updates.
        if (this._pointsObserver) {
          return;
        }
        this._pointsObserver = new MutationObserver(this._buildPathFromPoints.bind(this));
        this._pointsObserver.observe(this, {
          childList: true
        });
      },
  
      _clearListener: function(name) {
        if (this._listeners[name]) {
          google.maps.event.removeListener(this._listeners[name]);
          this._listeners[name] = null;
        }
      },
  
      _convertStrokePosition: function() {
        return google.maps.StrokePosition && this.strokePosition ?
            google.maps.StrokePosition[this.strokePosition.toUpperCase()] : 0;
      },
  
      _createPoly: function() {
        // Build poly's path and register mutation listeners on first creation.
        if (!this.path) {
          this._setPath(new google.maps.MVCArray());
          google.maps.event.addListener(this.path, 'insert_at', this._startEditing.bind(this));
          google.maps.event.addListener(this.path, 'set_at', this._updatePoint.bind(this));
          this._buildPathFromPoints();
        }
  
        var options = {
          clickable: this.clickable || this.draggable,  // draggable must be clickable to work.
          draggable: this.draggable,
          editable: this.editable,
          geodesic: this.geodesic,
          map: this.map,
          path: this.path,
          strokeColor: this.strokeColor,
          strokeOpacity: this.strokeOpacity,
          strokePosition: this._convertStrokePosition(),
          strokeWeight: this.strokeWeight,
          visible: !this.hidden,
          zIndex: this.zIndex
        };
  
        if (this.closed) {
          options.fillColor = this.fillColor;
          options.fillOpacity = this.fillOpacity;
          this._setPoly(new google.maps.Polygon(options));
        } else {
          options.icons = this.icons;
          this._setPoly(new google.maps.Polyline(options));
        }
  
        this._listeners = {};
      },
  
      _forwardEvent: function(name) {
        this._listeners[name] = google.maps.event.addListener(this.poly, name, function(event) {
          this.fire('google-map-poly-' + name, event);
        }.bind(this));
      },
  
      _startEditing: function(index) {
        if (this._building) {
          // Ignore changes while building path.
          return;
        }
  
        // Signal start of editing when first vertex inserted, end when map clicked.
        if (!this.editing) {
          this._setEditing(true);
          // The poly path and google-map-point elements lose sync once the user starts adding points,
          // so invalidate the _points array.
          this._points = null;
          google.maps.event.addListenerOnce(this.map, 'click', function() {
            this._setEditing(false);
            this.fire('google-map-poly-path-updated', this.path);
          }.bind(this));
        }
      },
  
      _updatePoint: function(index, vertex) {
        // Ignore changes if path is out of sync with google-map-point elements.
        if (!this._points) {
          return;
        }
  
        // Update existing point so bound properties are updated. too.
        this._points[index].latitude = vertex.lat();
        this._points[index].longitude = vertex.lng();
      }
    });
  </script>