/** * @name MarkerManager * @version 1.1 * @copyright (c) 2007 Google Inc. * @author Doug Ricket, others * * @fileoverview Marker manager is an interface between the map and the user, * designed to manage adding and removing many points when the viewport changes. *

* How it Works:
* The MarkerManager places its markers onto a grid, similar to the map tiles. * When the user moves the viewport, it computes which grid cells have * entered or left the viewport, and shows or hides all the markers in those * cells. * (If the users scrolls the viewport beyond the markers that are loaded, * no markers will be visible until the EVENT_moveend * triggers an update.) * In practical consequences, this allows 10,000 markers to be distributed over * a large area, and as long as only 100-200 are visible in any given viewport, * the user will see good performance corresponding to the 100 visible markers, * rather than poor performance corresponding to the total 10,000 markers. * Note that some code is optimized for speed over space, * with the goal of accommodating thousands of markers. */ /* * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /** * @name MarkerManagerOptions * @class This class represents optional arguments to the {@link MarkerManager} * constructor. * @property {Number} [maxZoom] Sets the maximum zoom level monitored by a * marker manager. If not given, the manager assumes the maximum map zoom * level. This value is also used when markers are added to the manager * without the optional {@link maxZoom} parameter. * @property {Number} [borderPadding] Specifies, in pixels, the extra padding * outside the map's current viewport monitored by a manager. Markers that * fall within this padding are added to the map, even if they are not fully * visible. * @property {Boolean} [trackMarkers=false] Indicates whether or not a marker * manager should track markers' movements. If you wish to move managed * markers using the {@link setPoint}/{@link setLatLng} methods, * this option should be set to {@link true}. */ /** * Creates a new MarkerManager that will show/hide markers on a map. * * @constructor * @param {Map} map The map to manage. * @param {Object} opt_opts A container for optional arguments: * {Number} maxZoom The maximum zoom level for which to create tiles. * {Number} borderPadding The width in pixels beyond the map border, * where markers should be display. * {Boolean} trackMarkers Whether or not this manager should track marker * movements. */ function MarkerManager(map, opt_opts) { var me = this; me.map_ = map; me.mapZoom_ = map.getZoom(); me.projection_ = map.getCurrentMapType().getProjection(); opt_opts = opt_opts || {}; me.tileSize_ = MarkerManager.DEFAULT_TILE_SIZE_; var mapTypes = map.getMapTypes(); var mapMaxZoom = mapTypes[0].getMaximumResolution(); for (var i = 0; i < mapTypes.length; i++) { var mapTypeMaxZoom = mapTypes[i].getMaximumResolution(); if (mapTypeMaxZoom > mapMaxZoom) { mapMaxZoom = mapTypeMaxZoom; } } me.maxZoom_ = opt_opts.maxZoom || mapMaxZoom; me.trackMarkers_ = opt_opts.trackMarkers; me.show_ = opt_opts.show || true; var padding; if (typeof opt_opts.borderPadding === "number") { padding = opt_opts.borderPadding; } else { padding = MarkerManager.DEFAULT_BORDER_PADDING_; } // The padding in pixels beyond the viewport, where we will pre-load markers. me.swPadding_ = new GSize(-padding, padding); me.nePadding_ = new GSize(padding, -padding); me.borderPadding_ = padding; me.gridWidth_ = []; me.grid_ = []; me.grid_[me.maxZoom_] = []; me.numMarkers_ = []; me.numMarkers_[me.maxZoom_] = 0; GEvent.bind(map, "moveend", me, me.onMapMoveEnd_); // NOTE: These two closures provide easy access to the map. // They are used as callbacks, not as methods. me.removeOverlay_ = function (marker) { map.removeOverlay(marker); me.shownMarkers_--; }; me.addOverlay_ = function (marker) { if (me.show_) { map.addOverlay(marker); me.shownMarkers_++; } }; me.resetManager_(); me.shownMarkers_ = 0; me.shownBounds_ = me.getMapGridBounds_(); } // Static constants: MarkerManager.DEFAULT_TILE_SIZE_ = 1024; MarkerManager.DEFAULT_BORDER_PADDING_ = 100; MarkerManager.MERCATOR_ZOOM_LEVEL_ZERO_RANGE = 256; /** * Initializes MarkerManager arrays for all zoom levels * Called by constructor and by clearAllMarkers */ MarkerManager.prototype.resetManager_ = function () { var me = this; var mapWidth = MarkerManager.MERCATOR_ZOOM_LEVEL_ZERO_RANGE; for (var zoom = 0; zoom <= me.maxZoom_; ++zoom) { me.grid_[zoom] = []; me.numMarkers_[zoom] = 0; me.gridWidth_[zoom] = Math.ceil(mapWidth / me.tileSize_); mapWidth <<= 1; } }; /** * Removes all markers in the manager, and * removes any visible markers from the map. */ MarkerManager.prototype.clearMarkers = function () { var me = this; me.processAll_(me.shownBounds_, me.removeOverlay_); me.resetManager_(); }; /** * Gets the tile coordinate for a given latlng point. * * @param {LatLng} latlng The geographical point. * @param {Number} zoom The zoom level. * @param {GSize} padding The padding used to shift the pixel coordinate. * Used for expanding a bounds to include an extra padding * of pixels surrounding the bounds. * @return {GPoint} The point in tile coordinates. * */ MarkerManager.prototype.getTilePoint_ = function (latlng, zoom, padding) { var pixelPoint = this.projection_.fromLatLngToPixel(latlng, zoom); return new GPoint( Math.floor((pixelPoint.x + padding.width) / this.tileSize_), Math.floor((pixelPoint.y + padding.height) / this.tileSize_)); }; /** * Finds the appropriate place to add the marker to the grid. * Optimized for speed; does not actually add the marker to the map. * Designed for batch-processing thousands of markers. * * @param {Marker} marker The marker to add. * @param {Number} minZoom The minimum zoom for displaying the marker. * @param {Number} maxZoom The maximum zoom for displaying the marker. */ MarkerManager.prototype.addMarkerBatch_ = function (marker, minZoom, maxZoom) { var mPoint = marker.getPoint(); marker.MarkerManager_minZoom = minZoom; // Tracking markers is expensive, so we do this only if the // user explicitly requested it when creating marker manager. if (this.trackMarkers_) { GEvent.bind(marker, "changed", this, this.onMarkerMoved_); } var gridPoint = this.getTilePoint_(mPoint, maxZoom, GSize.ZERO); for (var zoom = maxZoom; zoom >= minZoom; zoom--) { var cell = this.getGridCellCreate_(gridPoint.x, gridPoint.y, zoom); cell.push(marker); gridPoint.x = gridPoint.x >> 1; gridPoint.y = gridPoint.y >> 1; } }; /** * Returns whether or not the given point is visible in the shown bounds. This * is a helper method that takes care of the corner case, when shownBounds have * negative minX value. * * @param {Point} point a point on a grid. * @return {Boolean} Whether or not the given point is visible in the currently * shown bounds. */ MarkerManager.prototype.isGridPointVisible_ = function (point) { var me = this; var vertical = me.shownBounds_.minY <= point.y && point.y <= me.shownBounds_.maxY; var minX = me.shownBounds_.minX; var horizontal = minX <= point.x && point.x <= me.shownBounds_.maxX; if (!horizontal && minX < 0) { // Shifts the negative part of the rectangle. As point.x is always less // than grid width, only test shifted minX .. 0 part of the shown bounds. var width = me.gridWidth_[me.shownBounds_.z]; horizontal = minX + width <= point.x && point.x <= width - 1; } return vertical && horizontal; }; /** * Reacts to a notification from a marker that it has moved to a new location. * It scans the grid all all zoom levels and moves the marker from the old grid * location to a new grid location. * * @param {Marker} marker The marker that moved. * @param {LatLng} oldPoint The old position of the marker. * @param {LatLng} newPoint The new position of the marker. */ MarkerManager.prototype.onMarkerMoved_ = function (marker, oldPoint, newPoint) { // NOTE: We do not know the minimum or maximum zoom the marker was // added at, so we start at the absolute maximum. Whenever we successfully // remove a marker at a given zoom, we add it at the new grid coordinates. var me = this; var zoom = me.maxZoom_; var changed = false; var oldGrid = me.getTilePoint_(oldPoint, zoom, GSize.ZERO); var newGrid = me.getTilePoint_(newPoint, zoom, GSize.ZERO); while (zoom >= 0 && (oldGrid.x !== newGrid.x || oldGrid.y !== newGrid.y)) { var cell = me.getGridCellNoCreate_(oldGrid.x, oldGrid.y, zoom); if (cell) { if (me.removeFromArray_(cell, marker)) { me.getGridCellCreate_(newGrid.x, newGrid.y, zoom).push(marker); } } // For the current zoom we also need to update the map. Markers that no // longer are visible are removed from the map. Markers that moved into // the shown bounds are added to the map. This also lets us keep the count // of visible markers up to date. if (zoom === me.mapZoom_) { if (me.isGridPointVisible_(oldGrid)) { if (!me.isGridPointVisible_(newGrid)) { me.removeOverlay_(marker); changed = true; } } else { if (me.isGridPointVisible_(newGrid)) { me.addOverlay_(marker); changed = true; } } } oldGrid.x = oldGrid.x >> 1; oldGrid.y = oldGrid.y >> 1; newGrid.x = newGrid.x >> 1; newGrid.y = newGrid.y >> 1; --zoom; } if (changed) { me.notifyListeners_(); } }; /** * Removes marker from the manager and from the map * (if it's currently visible). * @param {GMarker} marker The marker to delete. */ MarkerManager.prototype.removeMarker = function (marker) { var me = this; var zoom = me.maxZoom_; var changed = false; var point = marker.getPoint(); var grid = me.getTilePoint_(point, zoom, GSize.ZERO); while (zoom >= 0) { var cell = me.getGridCellNoCreate_(grid.x, grid.y, zoom); if (cell) { me.removeFromArray_(cell, marker); } // For the current zoom we also need to update the map. Markers that no // longer are visible are removed from the map. This also lets us keep the count // of visible markers up to date. if (zoom === me.mapZoom_) { if (me.isGridPointVisible_(grid)) { me.removeOverlay_(marker); changed = true; } } grid.x = grid.x >> 1; grid.y = grid.y >> 1; --zoom; } if (changed) { me.notifyListeners_(); } me.numMarkers_[marker.MarkerManager_minZoom]--; }; /** * Add many markers at once. * Does not actually update the map, just the internal grid. * * @param {Array of Marker} markers The markers to add. * @param {Number} minZoom The minimum zoom level to display the markers. * @param {Number} opt_maxZoom The maximum zoom level to display the markers. */ MarkerManager.prototype.addMarkers = function (markers, minZoom, opt_maxZoom) { var maxZoom = this.getOptMaxZoom_(opt_maxZoom); for (var i = markers.length - 1; i >= 0; i--) { this.addMarkerBatch_(markers[i], minZoom, maxZoom); } this.numMarkers_[minZoom] += markers.length; }; /** * Returns the value of the optional maximum zoom. This method is defined so * that we have just one place where optional maximum zoom is calculated. * * @param {Number} opt_maxZoom The optinal maximum zoom. * @return The maximum zoom. */ MarkerManager.prototype.getOptMaxZoom_ = function (opt_maxZoom) { return opt_maxZoom || this.maxZoom_; }; /** * Calculates the total number of markers potentially visible at a given * zoom level. * * @param {Number} zoom The zoom level to check. */ MarkerManager.prototype.getMarkerCount = function (zoom) { var total = 0; for (var z = 0; z <= zoom; z++) { total += this.numMarkers_[z]; } return total; }; /** * Returns a marker given latitude, longitude and zoom. If the marker does not * exist, the method will return a new marker. If a new marker is created, * it will NOT be added to the manager. * * @param {Number} lat - the latitude of a marker. * @param {Number} lng - the longitude of a marker. * @param {Number} zoom - the zoom level * @return {GMarker} marker - the marker found at lat and lng */ MarkerManager.prototype.getMarker = function(lat, lng, zoom) { var me = this; var mPoint = new GLatLng(lat, lng); var gridPoint = me.getTilePoint_(mPoint, zoom, GSize.ZERO); var marker = new GMarker(mPoint); var cellArray = me.getGridCellNoCreate_(gridPoint.x, gridPoint.y, zoom); if(cellArray != undefined){ for (var i = 0; i < cellArray.length; i++) { if(lat == cellArray[i].getLatLng().lat() && lng == cellArray[i].getLatLng().lng()) { marker = cellArray[i]; } } } return marker; }; /** * Add a single marker to the map. * * @param {Marker} marker The marker to add. * @param {Number} minZoom The minimum zoom level to display the marker. * @param {Number} opt_maxZoom The maximum zoom level to display the marker. */ MarkerManager.prototype.addMarker = function (marker, minZoom, opt_maxZoom) { var me = this; var maxZoom = this.getOptMaxZoom_(opt_maxZoom); me.addMarkerBatch_(marker, minZoom, maxZoom); var gridPoint = me.getTilePoint_(marker.getPoint(), me.mapZoom_, GSize.ZERO); if (me.isGridPointVisible_(gridPoint) && minZoom <= me.shownBounds_.z && me.shownBounds_.z <= maxZoom) { me.addOverlay_(marker); me.notifyListeners_(); } this.numMarkers_[minZoom]++; }; /** * Returns true if this bounds (inclusively) contains the given point. * @param {Point} point The point to test. * @return {Boolean} This Bounds contains the given Point. */ GBounds.prototype.containsPoint = function (point) { var outer = this; return (outer.minX <= point.x && outer.maxX >= point.x && outer.minY <= point.y && outer.maxY >= point.y); }; /** * Get a cell in the grid, creating it first if necessary. * * Optimization candidate * * @param {Number} x The x coordinate of the cell. * @param {Number} y The y coordinate of the cell. * @param {Number} z The z coordinate of the cell. * @return {Array} The cell in the array. */ MarkerManager.prototype.getGridCellCreate_ = function (x, y, z) { var grid = this.grid_[z]; if (x < 0) { x += this.gridWidth_[z]; } var gridCol = grid[x]; if (!gridCol) { gridCol = grid[x] = []; return (gridCol[y] = []); } var gridCell = gridCol[y]; if (!gridCell) { return (gridCol[y] = []); } return gridCell; }; /** * Get a cell in the grid, returning undefined if it does not exist. * * NOTE: Optimized for speed -- otherwise could combine with getGridCellCreate_. * * @param {Number} x The x coordinate of the cell. * @param {Number} y The y coordinate of the cell. * @param {Number} z The z coordinate of the cell. * @return {Array} The cell in the array. */ MarkerManager.prototype.getGridCellNoCreate_ = function (x, y, z) { var grid = this.grid_[z]; if (x < 0) { x += this.gridWidth_[z]; } var gridCol = grid[x]; return gridCol ? gridCol[y] : undefined; }; /** * Turns at geographical bounds into a grid-space bounds. * * @param {LatLngBounds} bounds The geographical bounds. * @param {Number} zoom The zoom level of the bounds. * @param {GSize} swPadding The padding in pixels to extend beyond the * given bounds. * @param {GSize} nePadding The padding in pixels to extend beyond the * given bounds. * @return {GBounds} The bounds in grid space. */ MarkerManager.prototype.getGridBounds_ = function (bounds, zoom, swPadding, nePadding) { zoom = Math.min(zoom, this.maxZoom_); var bl = bounds.getSouthWest(); var tr = bounds.getNorthEast(); var sw = this.getTilePoint_(bl, zoom, swPadding); var ne = this.getTilePoint_(tr, zoom, nePadding); var gw = this.gridWidth_[zoom]; // Crossing the prime meridian requires correction of bounds. if (tr.lng() < bl.lng() || ne.x < sw.x) { sw.x -= gw; } if (ne.x - sw.x + 1 >= gw) { // Computed grid bounds are larger than the world; truncate. sw.x = 0; ne.x = gw - 1; } var gridBounds = new GBounds([sw, ne]); gridBounds.z = zoom; return gridBounds; }; /** * Gets the grid-space bounds for the current map viewport. * * @return {Bounds} The bounds in grid space. */ MarkerManager.prototype.getMapGridBounds_ = function () { var me = this; return me.getGridBounds_(me.map_.getBounds(), me.mapZoom_, me.swPadding_, me.nePadding_); }; /** * Event listener for map:movend. * NOTE: Use a timeout so that the user is not blocked * from moving the map. * */ MarkerManager.prototype.onMapMoveEnd_ = function () { var me = this; me.objectSetTimeout_(this, this.updateMarkers_, 0); }; /** * Call a function or evaluate an expression after a specified number of * milliseconds. * * Equivalent to the standard window.setTimeout function, but the given * function executes as a method of this instance. So the function passed to * objectSetTimeout can contain references to this. * objectSetTimeout(this, function () { alert(this.x) }, 1000); * * @param {Object} object The target object. * @param {Function} command The command to run. * @param {Number} milliseconds The delay. * @return {Boolean} Success. */ MarkerManager.prototype.objectSetTimeout_ = function (object, command, milliseconds) { return window.setTimeout(function () { command.call(object); }, milliseconds); }; /** * Is this layer visible? * * Returns visibility setting * * @return {Boolean} Visible */ MarkerManager.prototype.visible = function () { return this.show_ ? true : false; }; /** * Returns true if the manager is hidden. * Otherwise returns false. * @return {Boolean} Hidden */ MarkerManager.prototype.isHidden = function () { return !this.show_; }; /** * Shows the manager if it's currently hidden. */ MarkerManager.prototype.show = function () { this.show_ = true; this.refresh(); }; /** * Hides the manager if it's currently visible */ MarkerManager.prototype.hide = function () { this.show_ = false; this.refresh(); }; /** * Toggles the visibility of the manager. */ MarkerManager.prototype.toggle = function () { this.show_ = !this.show_; this.refresh(); }; /** * Refresh forces the marker-manager into a good state. *
    *
  1. If never before initialized, shows all the markers.
  2. *
  3. If previously initialized, removes and re-adds all markers.
  4. *
*/ MarkerManager.prototype.refresh = function () { var me = this; if (me.shownMarkers_ > 0) { me.processAll_(me.shownBounds_, me.removeOverlay_); } // An extra check on me.show_ to increase performance (no need to processAll_) if (me.show_) { me.processAll_(me.shownBounds_, me.addOverlay_); } me.notifyListeners_(); }; /** * After the viewport may have changed, add or remove markers as needed. */ MarkerManager.prototype.updateMarkers_ = function () { var me = this; me.mapZoom_ = this.map_.getZoom(); var newBounds = me.getMapGridBounds_(); // If the move does not include new grid sections, // we have no work to do: if (newBounds.equals(me.shownBounds_) && newBounds.z === me.shownBounds_.z) { return; } if (newBounds.z !== me.shownBounds_.z) { me.processAll_(me.shownBounds_, me.removeOverlay_); if (me.show_) { // performance me.processAll_(newBounds, me.addOverlay_); } } else { // Remove markers: me.rectangleDiff_(me.shownBounds_, newBounds, me.removeCellMarkers_); // Add markers: if (me.show_) { // performance me.rectangleDiff_(newBounds, me.shownBounds_, me.addCellMarkers_); } } me.shownBounds_ = newBounds; me.notifyListeners_(); }; /** * Notify listeners when the state of what is displayed changes. */ MarkerManager.prototype.notifyListeners_ = function () { GEvent.trigger(this, "changed", this.shownBounds_, this.shownMarkers_); }; /** * Process all markers in the bounds provided, using a callback. * * @param {Bounds} bounds The bounds in grid space. * @param {Function} callback The function to call for each marker. */ MarkerManager.prototype.processAll_ = function (bounds, callback) { for (var x = bounds.minX; x <= bounds.maxX; x++) { for (var y = bounds.minY; y <= bounds.maxY; y++) { this.processCellMarkers_(x, y, bounds.z, callback); } } }; /** * Process all markers in the grid cell, using a callback. * * @param {Number} x The x coordinate of the cell. * @param {Number} y The y coordinate of the cell. * @param {Number} z The z coordinate of the cell. * @param {Function} callback The function to call for each marker. */ MarkerManager.prototype.processCellMarkers_ = function (x, y, z, callback) { var cell = this.getGridCellNoCreate_(x, y, z); if (cell) { for (var i = cell.length - 1; i >= 0; i--) { callback(cell[i]); } } }; /** * Remove all markers in a grid cell. * * @param {Number} x The x coordinate of the cell. * @param {Number} y The y coordinate of the cell. * @param {Number} z The z coordinate of the cell. */ MarkerManager.prototype.removeCellMarkers_ = function (x, y, z) { this.processCellMarkers_(x, y, z, this.removeOverlay_); }; /** * Add all markers in a grid cell. * * @param {Number} x The x coordinate of the cell. * @param {Number} y The y coordinate of the cell. * @param {Number} z The z coordinate of the cell. */ MarkerManager.prototype.addCellMarkers_ = function (x, y, z) { this.processCellMarkers_(x, y, z, this.addOverlay_); }; /** * Use the rectangleDiffCoords_ function to process all grid cells * that are in bounds1 but not bounds2, using a callback, and using * the current MarkerManager object as the instance. * * Pass the z parameter to the callback in addition to x and y. * * @param {Bounds} bounds1 The bounds of all points we may process. * @param {Bounds} bounds2 The bounds of points to exclude. * @param {Function} callback The callback function to call * for each grid coordinate (x, y, z). */ MarkerManager.prototype.rectangleDiff_ = function (bounds1, bounds2, callback) { var me = this; me.rectangleDiffCoords_(bounds1, bounds2, function (x, y) { callback.apply(me, [x, y, bounds1.z]); }); }; /** * Calls the function for all points in bounds1, not in bounds2 * * @param {Bounds} bounds1 The bounds of all points we may process. * @param {Bounds} bounds2 The bounds of points to exclude. * @param {Function} callback The callback function to call * for each grid coordinate. */ MarkerManager.prototype.rectangleDiffCoords_ = function (bounds1, bounds2, callback) { var minX1 = bounds1.minX; var minY1 = bounds1.minY; var maxX1 = bounds1.maxX; var maxY1 = bounds1.maxY; var minX2 = bounds2.minX; var minY2 = bounds2.minY; var maxX2 = bounds2.maxX; var maxY2 = bounds2.maxY; var x, y; for (x = minX1; x <= maxX1; x++) { // All x in R1 // All above: for (y = minY1; y <= maxY1 && y < minY2; y++) { // y in R1 above R2 callback(x, y); } // All below: for (y = Math.max(maxY2 + 1, minY1); // y in R1 below R2 y <= maxY1; y++) { callback(x, y); } } for (y = Math.max(minY1, minY2); y <= Math.min(maxY1, maxY2); y++) { // All y in R2 and in R1 // Strictly left: for (x = Math.min(maxX1 + 1, minX2) - 1; x >= minX1; x--) { // x in R1 left of R2 callback(x, y); } // Strictly right: for (x = Math.max(minX1, maxX2 + 1); // x in R1 right of R2 x <= maxX1; x++) { callback(x, y); } } }; /** * Removes value from array. O(N). * * @param {Array} array The array to modify. * @param {any} value The value to remove. * @param {Boolean} opt_notype Flag to disable type checking in equality. * @return {Number} The number of instances of value that were removed. */ MarkerManager.prototype.removeFromArray_ = function (array, value, opt_notype) { var shift = 0; for (var i = 0; i < array.length; ++i) { if (array[i] === value || (opt_notype && array[i] === value)) { array.splice(i--, 1); shift++; } } return shift; };