markerclusterer.js 19.5 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735
/**
 * @name MarkerClusterer
 * @version 1.0
 * @author Xiaoxi Wu
 * @copyright (c) 2009 Xiaoxi Wu
 * @fileoverview
 * This javascript library creates and manages per-zoom-level 
 * clusters for large amounts of markers (hundreds or thousands).
 * This library was inspired by the <a href="http://www.maptimize.com">
 * Maptimize</a> hosted clustering solution.
 * <br /><br/>
 * <b>How it works</b>:<br/>
 * The <code>MarkerClusterer</code> will group markers into clusters according to
 * their distance from a cluster's center. When a marker is added,
 * the marker cluster will find a position in all the clusters, and 
 * if it fails to find one, it will create a new cluster with the marker.
 * The number of markers in a cluster will be displayed
 * on the cluster marker. When the map viewport changes,
 * <code>MarkerClusterer</code> will destroy the clusters in the viewport 
 * and regroup them into new clusters.
 *
 */

/*
 * 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 MarkerClustererOptions
 * @class This class represents optional arguments to the {@link MarkerClusterer}
 * constructor.
 * @property {Number} [maxZoom] The max zoom level monitored by a
 * marker cluster. If not given, the marker cluster assumes the maximum map
 * zoom level. When maxZoom is reached or exceeded all markers will be shown
 * without cluster.
 * @property {Number} [gridSize=60] The grid size of a cluster in pixel. Each
 * cluster will be a square. If you want the algorithm to run faster, you can set
 * this value larger.
 * @property {Array of MarkerStyleOptions} [styles]
 * Custom styles for the cluster markers.
 * The array should be ordered according to increasing cluster size,
 * with the style for the smallest clusters first, and the style for the
 * largest clusters last.
 */

/**
 * @name MarkerStyleOptions
 * @class An array of these is passed into the {@link MarkerClustererOptions}
 * styles option.
 * @property {String} [url] Image url.
 * @property {Number} [height] Image height.
 * @property {Number} [height] Image width.
 * @property {Array of Number} [opt_anchor] Anchor for label text, like [24, 12]. 
 *    If not set, the text will align center and middle.
 * @property {String} [opt_textColor="black"] Text color.
 */

/**
 * Creates a new MarkerClusterer to cluster markers on the map.
 *
 * @constructor
 * @param {GMap2} map The map that the markers should be added to.
 * @param {Array of GMarker} opt_markers Initial set of markers to be clustered.
 * @param {MarkerClustererOptions} opt_opts A container for optional arguments.
 */
function MarkerClusterer(map, opt_markers, opt_opts) {
	// private members
	var clusters_ = [];
	var map_ = map;
	var maxZoom_ = null;
	var me_ = this;
	var gridSize_ = 60;
	var sizes = [53, 56, 66, 78, 90];
	var styles_ = [];
	var leftMarkers_ = [];
	var mcfn_ = null;

	var i = 0;
	for (i = 1; i <= 5; ++i) {
		styles_.push({
			'url': "http://gmaps-utility-library.googlecode.com/svn/trunk/markerclusterer/images/m" + i + ".png",
			'height': sizes[i - 1],
			'width': sizes[i - 1]
		});
	}

	if (typeof opt_opts === "object" && opt_opts !== null) {
		if (typeof opt_opts.gridSize === "number" && opt_opts.gridSize > 0) {
			gridSize_ = opt_opts.gridSize;
		}
		if (typeof opt_opts.maxZoom === "number") {
			maxZoom_ = opt_opts.maxZoom;
		}
		if (typeof opt_opts.styles === "object" && opt_opts.styles !== null && opt_opts.styles.length !== 0) {
			styles_ = opt_opts.styles;
		}
	}

	/**
	 * When we add a marker, the marker may not in the viewport of map, then we don't deal with it, instead
	 * we add the marker into a array called leftMarkers_. When we reset MarkerClusterer we should add the
	 * leftMarkers_ into MarkerClusterer.
	 */
	function addLeftMarkers_() {
		if (leftMarkers_.length === 0) {
			return;
		}
		var leftMarkers = [];
		for (i = 0; i < leftMarkers_.length; ++i) {
			me_.addMarker(leftMarkers_[i], true, null, null, true);
		}
		leftMarkers_ = leftMarkers;
	}

	/**
	 * Get cluster marker images of this marker cluster. Mostly used by {@link Cluster}
	 * @private
	 * @return {Array of String}
	 */
	this.getStyles_ = function () {
		return styles_;
	};

	/**
	 * Remove all markers from MarkerClusterer.
	 */
	this.clearMarkers = function () {
		for (var i = 0; i < clusters_.length; ++i) {
			if (typeof clusters_[i] !== "undefined" && clusters_[i] !== null) {
				clusters_[i].clearMarkers();
			}
		}
		clusters_ = [];
		leftMarkers_ = [];
		GEvent.removeListener(mcfn_);
	};

	/**
	 * Check a marker, whether it is in current map viewport.
	 * @private
	 * @return {Boolean} if it is in current map viewport
	 */
	function isMarkerInViewport_(marker) {
		return map_.getBounds().containsLatLng(marker.getLatLng());
	}

	/**
	 * When reset MarkerClusterer, there will be some markers get out of its cluster.
	 * These markers should be add to new clusters.
	 * @param {Array of GMarker} markers Markers to add.
	 */
	function reAddMarkers_(markers) {
		var len = markers.length;
		var clusters = [];
		for (var i = len - 1; i >= 0; --i) {
			me_.addMarker(markers[i].marker, true, markers[i].isAdded, clusters, true);
		}
		addLeftMarkers_();
	}

	/**
	 * Add a marker.
	 * @private
	 * @param {GMarker} marker Marker you want to add
	 * @param {Boolean} opt_isNodraw Whether redraw the cluster contained the marker
	 * @param {Boolean} opt_isAdded Whether the marker is added to map. Never use it.
	 * @param {Array of Cluster} opt_clusters Provide a list of clusters, the marker
	 *     cluster will only check these cluster where the marker should join.
	 */
	this.addMarker = function (marker, opt_isNodraw, opt_isAdded, opt_clusters, opt_isNoCheck) {
		if (opt_isNoCheck !== true) {
			if (!isMarkerInViewport_(marker)) {
				leftMarkers_.push(marker);
				return;
			}
		}

		var isAdded = opt_isAdded;
		var clusters = opt_clusters;
		var pos = map_.fromLatLngToDivPixel(marker.getLatLng());

		if (typeof isAdded !== "boolean") {
			isAdded = false;
		}
		if (typeof clusters !== "object" || clusters === null) {
			clusters = clusters_;
		}

		var length = clusters.length;
		var cluster = null;
		for (var i = length - 1; i >= 0; i--) {
			cluster = clusters[i];
			var center = cluster.getCenter();
			if (center === null) {
				continue;
			}
			center = map_.fromLatLngToDivPixel(center);

			// Found a cluster which contains the marker.
			if (pos.x >= center.x - gridSize_ && pos.x <= center.x + gridSize_ &&
					pos.y >= center.y - gridSize_ && pos.y <= center.y + gridSize_) {
				cluster.addMarker({
					'isAdded': isAdded,
					'marker': marker
				});
				if (!opt_isNodraw) {
					cluster.redraw_();
				}
				return;
			}
		}

		// No cluster contain the marker, create a new cluster.
		cluster = new Cluster(this, map);
		cluster.addMarker({
			'isAdded': isAdded,
			'marker': marker
		});
		if (!opt_isNodraw) {
			cluster.redraw_();
		}

		// Add this cluster both in clusters provided and clusters_
		clusters.push(cluster);
		if (clusters !== clusters_) {
			clusters_.push(cluster);
		}
	};

	/**
	 * Remove a marker.
	 *
	 * @param {GMarker} marker The marker you want to remove.
	 */

	this.removeMarker = function (marker) {
		for (var i = 0; i < clusters_.length; ++i) {
			if (clusters_[i].remove(marker)) {
				clusters_[i].redraw_();
				return;
			}
		}
	};

	/**
	 * Redraw all clusters in viewport.
	 */
	this.redraw_ = function () {
		var clusters = this.getClustersInViewport_();
		for (var i = 0; i < clusters.length; ++i) {
			clusters[i].redraw_(true);
		}
	};

	/**
	 * Get all clusters in viewport.
	 * @return {Array of Cluster}
	 */
	this.getClustersInViewport_ = function () {
		var clusters = [];
		var curBounds = map_.getBounds();
		for (var i = 0; i < clusters_.length; i ++) {
			if (clusters_[i].isInBounds(curBounds)) {
				clusters.push(clusters_[i]);
			}
		}
		return clusters;
	};

	/**
	 * Get max zoom level.
	 * @private
	 * @return {Number}
	 */
	this.getMaxZoom_ = function () {
		return maxZoom_;
	};

	/**
	 * Get map object.
	 * @private
	 * @return {GMap2}
	 */
	this.getMap_ = function () {
		return map_;
	};

	/**
	 * Get grid size
	 * @private
	 * @return {Number}
	 */
	this.getGridSize_ = function () {
		return gridSize_;
	};

	/**
	 * Get total number of markers.
	 * @return {Number}
	 */
	this.getTotalMarkers = function () {
		var result = 0;
		for (var i = 0; i < clusters_.length; ++i) {
			result += clusters_[i].getTotalMarkers();
		}
		return result;
	};

	/**
	 * Get total number of clusters.
	 * @return {int}
	 */
	this.getTotalClusters = function () {
		return clusters_.length;
	};

	/**
	 * Collect all markers of clusters in viewport and regroup them.
	 */
	this.resetViewport = function () {
		var clusters = this.getClustersInViewport_();
		var tmpMarkers = [];
		var removed = 0;

		for (var i = 0; i < clusters.length; ++i) {
			var cluster = clusters[i];
			var oldZoom = cluster.getCurrentZoom();
			if (oldZoom === null) {
				continue;
			}
			var curZoom = map_.getZoom();
			if (curZoom !== oldZoom) {

				// If the cluster zoom level changed then destroy the cluster
				// and collect its markers.
				var mks = cluster.getMarkers();
				for (var j = 0; j < mks.length; ++j) {
					var newMarker = {
							'isAdded': false,
							'marker': mks[j].marker
					};
					tmpMarkers.push(newMarker);
				}
				cluster.clearMarkers();
				removed++;
				for (j = 0; j < clusters_.length; ++j) {
					if (cluster === clusters_[j]) {
						clusters_.splice(j, 1);
					}
				}
			}
		}

		// Add the markers collected into marker cluster to reset
		reAddMarkers_(tmpMarkers);
		this.redraw_();
	};


	/**
	 * Add a set of markers.
	 *
	 * @param {Array of GMarker} markers The markers you want to add.
	 */
	this.addMarkers = function (markers) {
		for (var i = 0; i < markers.length; ++i) {
			this.addMarker(markers[i], true);
		}
		this.redraw_();
	};

	// initialize
	if (typeof opt_markers === "object" && opt_markers !== null) {
		this.addMarkers(opt_markers);
	}

	// when map move end, regroup.
	mcfn_ = GEvent.addListener(map_, "moveend", function () {
		me_.resetViewport();
	});
}

/**
 * Create a cluster to collect markers.
 * A cluster includes some markers which are in a block of area.
 * If there are more than one markers in cluster, the cluster
 * will create a {@link ClusterMarker_} and show the total number
 * of markers in cluster.
 *
 * @constructor
 * @private
 * @param {MarkerClusterer} markerClusterer The marker cluster object
 */
function Cluster(markerClusterer) {
	var center_ = null;
	var markers_ = [];
	var markerClusterer_ = markerClusterer;
	var map_ = markerClusterer.getMap_();
	var clusterMarker_ = null;
	var zoom_ = map_.getZoom();

	/**
	 * Get markers of this cluster.
	 *
	 * @return {Array of GMarker}
	 */
	this.getMarkers = function () {
		return markers_;
	};

	/**
	 * If this cluster intersects certain bounds.
	 *
	 * @param {GLatLngBounds} bounds A bounds to test
	 * @return {Boolean} Is this cluster intersects the bounds
	 */
	this.isInBounds = function (bounds) {
		if (center_ === null) {
			return false;
		}

		if (!bounds) {
			bounds = map_.getBounds();
		}
		var sw = map_.fromLatLngToDivPixel(bounds.getSouthWest());
		var ne = map_.fromLatLngToDivPixel(bounds.getNorthEast());

		var centerxy = map_.fromLatLngToDivPixel(center_);
		var inViewport = true;
		var gridSize = markerClusterer.getGridSize_();
		if (zoom_ !== map_.getZoom()) {
			var dl = map_.getZoom() - zoom_;
			gridSize = Math.pow(2, dl) * gridSize;
		}
		if (ne.x !== sw.x && (centerxy.x + gridSize < sw.x || centerxy.x - gridSize > ne.x)) {
			inViewport = false;
		}
		if (inViewport && (centerxy.y + gridSize < ne.y || centerxy.y - gridSize > sw.y)) {
			inViewport = false;
		}
		return inViewport;
	};

	/**
	 * Get cluster center.
	 *
	 * @return {GLatLng}
	 */
	this.getCenter = function () {
		return center_;
	};

	/**
	 * Add a marker.
	 *
	 * @param {Object} marker An object of marker you want to add:
	 *   {Boolean} isAdded If the marker is added on map.
	 *   {GMarker} marker The marker you want to add.
	 */
	this.addMarker = function (marker) {
		if (center_ === null) {
			/*var pos = marker['marker'].getLatLng();
       pos = map.fromLatLngToContainerPixel(pos);
       pos.x = parseInt(pos.x - pos.x % (GRIDWIDTH * 2) + GRIDWIDTH);
       pos.y = parseInt(pos.y - pos.y % (GRIDWIDTH * 2) + GRIDWIDTH);
       center = map.fromContainerPixelToLatLng(pos);*/
			center_ = marker.marker.getLatLng();
		}
		markers_.push(marker);
	};

	/**
	 * Remove a marker from cluster.
	 *
	 * @param {GMarker} marker The marker you want to remove.
	 * @return {Boolean} Whether find the marker to be removed.
	 */
	this.removeMarker = function (marker) {
		for (var i = 0; i < markers_.length; ++i) {
			if (marker === markers_[i].marker) {
				if (markers_[i].isAdded) {
					map_.removeOverlay(markers_[i].marker);
				}
				markers_.splice(i, 1);
				return true;
			}
		}
		return false;
	};

	/**
	 * Get current zoom level of this cluster.
	 * Note: the cluster zoom level and map zoom level not always the same.
	 *
	 * @return {Number}
	 */
	this.getCurrentZoom = function () {
		return zoom_;
	};

	/**
	 * Redraw a cluster.
	 * @private
	 * @param {Boolean} isForce If redraw by force, no matter if the cluster is
	 *     in viewport.
	 */
	this.redraw_ = function (isForce) {
		if (!isForce && !this.isInBounds()) {
			return;
		}

		// Set cluster zoom level.
		zoom_ = map_.getZoom();
		var i = 0;
		var mz = markerClusterer.getMaxZoom_();
		if (mz === null) {
			mz = map_.getCurrentMapType().getMaximumResolution();
		}
		if (zoom_ >= mz || this.getTotalMarkers() === 1) {

			// If current zoom level is beyond the max zoom level or the cluster
			// have only one marker, the marker(s) in cluster will be showed on map.
			for (i = 0; i < markers_.length; ++i) {
				if (markers_[i].isAdded) {
					if (markers_[i].marker.isHidden()) {
						markers_[i].marker.show();
					}
				} else {
					map_.addOverlay(markers_[i].marker);
					markers_[i].isAdded = true;
				}
			}
			if (clusterMarker_ !== null) {
				clusterMarker_.hide();
			}
		} else {
			// Else add a cluster marker on map to show the number of markers in
			// this cluster.
			for (i = 0; i < markers_.length; ++i) {
				if (markers_[i].isAdded && (!markers_[i].marker.isHidden())) {
					markers_[i].marker.hide();
				}
			}
			if (clusterMarker_ === null) {
				clusterMarker_ = new ClusterMarker_(center_, this.getTotalMarkers(), markerClusterer_.getStyles_(), markerClusterer_.getGridSize_());
				map_.addOverlay(clusterMarker_);
			} else {
				if (clusterMarker_.isHidden()) {
					clusterMarker_.show();
				}
				clusterMarker_.redraw(true);
			}
		}
	};

	/**
	 * Remove all the markers from this cluster.
	 */
	this.clearMarkers = function () {
		if (clusterMarker_ !== null) {
			map_.removeOverlay(clusterMarker_);
		}
		for (var i = 0; i < markers_.length; ++i) {
			if (markers_[i].isAdded) {
				map_.removeOverlay(markers_[i].marker);
			}
		}
		markers_ = [];
	};

	/**
	 * Get number of markers.
	 * @return {Number}
	 */
	this.getTotalMarkers = function () {
		return markers_.length;
	};
}

/**
 * ClusterMarker_ creates a marker that shows the number of markers that
 * a cluster contains.
 *
 * @constructor
 * @private
 * @param {GLatLng} latlng Marker's lat and lng.
 * @param {Number} count Number to show.
 * @param {Array of Object} styles The image list to be showed:
 *   {String} url Image url.
 *   {Number} height Image height.
 *   {Number} width Image width.
 *   {Array of Number} anchor Text anchor of image left and top.
 *   {String} textColor text color.
 * @param {Number} padding Padding of marker center.
 */
function ClusterMarker_(latlng, count, styles, padding) {
	var index = 0;
	var dv = count;
	while (dv !== 0) {
		dv = parseInt(dv / 10, 10);
		index ++;
	}

	if (styles.length < index) {
		index = styles.length;
	}
	this.url_ = styles[index - 1].url;
	this.height_ = styles[index - 1].height;
	this.width_ = styles[index - 1].width;
	this.textColor_ = styles[index - 1].opt_textColor;
	this.anchor_ = styles[index - 1].opt_anchor;
	this.latlng_ = latlng;
	this.index_ = index;
	this.styles_ = styles;
	this.text_ = count;
	this.padding_ = padding;
}

//ClusterMarker_.prototype = new GOverlay();

/**
 * Initialize cluster marker.
 * @private
 */
ClusterMarker_.prototype.initialize = function (map) {
	this.map_ = map;
	var div = document.createElement("div");
	var latlng = this.latlng_;
	var pos = map.fromLatLngToDivPixel(latlng);
	pos.x -= parseInt(this.width_ / 2, 10);
	pos.y -= parseInt(this.height_ / 2, 10);
	var mstyle = "";
	if (document.all) {
		mstyle = 'filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale,src="' + this.url_ + '");';
	} else {
		mstyle = "background:url(" + this.url_ + ");";
	}
	if (typeof this.anchor_ === "object") {
		if (typeof this.anchor_[0] === "number" && this.anchor_[0] > 0 && this.anchor_[0] < this.height_) {
			mstyle += 'height:' + (this.height_ - this.anchor_[0]) + 'px;padding-top:' + this.anchor_[0] + 'px;';
		} else {
			mstyle += 'height:' + this.height_ + 'px;line-height:' + this.height_ + 'px;';
		}
		if (typeof this.anchor_[1] === "number" && this.anchor_[1] > 0 && this.anchor_[1] < this.width_) {
			mstyle += 'width:' + (this.width_ - this.anchor_[1]) + 'px;padding-left:' + this.anchor_[1] + 'px;';
		} else {
			mstyle += 'width:' + this.width_ + 'px;text-align:center;';
		}
	} else {
		mstyle += 'height:' + this.height_ + 'px;line-height:' + this.height_ + 'px;';
		mstyle += 'width:' + this.width_ + 'px;text-align:center;';
	}
	var txtColor = this.textColor_ ? this.textColor_ : 'black';

	div.style.cssText = mstyle + 'cursor:pointer;top:' + pos.y + "px;left:" +
	pos.x + "px;color:" + txtColor +  ";position:absolute;font-size:11px;" +
	'font-family:Arial,sans-serif;font-weight:bold';
	div.innerHTML = this.text_;
	map.getPane(G_MAP_MAP_PANE).appendChild(div);
	var padding = this.padding_;
	GEvent.addDomListener(div, "click", function () {
		var pos = map.fromLatLngToDivPixel(latlng);
		var sw = new GPoint(pos.x - padding, pos.y + padding);
		sw = map.fromDivPixelToLatLng(sw);
		var ne = new GPoint(pos.x + padding, pos.y - padding);
		ne = map.fromDivPixelToLatLng(ne);
		var zoom = map.getBoundsZoomLevel(new GLatLngBounds(sw, ne), map.getSize());
		map.setCenter(latlng, zoom);
	});
	this.div_ = div;
};

/**
 * Remove this overlay.
 * @private
 */
ClusterMarker_.prototype.remove = function () {
	this.div_.parentNode.removeChild(this.div_);
};

/**
 * Copy this overlay.
 * @private
 */
ClusterMarker_.prototype.copy = function () {
	return new ClusterMarker_(this.latlng_, this.index_, this.text_, this.styles_, this.padding_);
};

/**
 * Redraw this overlay.
 * @private
 */
ClusterMarker_.prototype.redraw = function (force) {
	if (!force) {
		return;
	}
	var pos = this.map_.fromLatLngToDivPixel(this.latlng_);
	pos.x -= parseInt(this.width_ / 2, 10);
	pos.y -= parseInt(this.height_ / 2, 10);
	this.div_.style.top =  pos.y + "px";
	this.div_.style.left = pos.x + "px";
};

/**
 * Hide this cluster marker.
 */
ClusterMarker_.prototype.hide = function () {
	this.div_.style.display = "none";
};

/**
 * Show this cluster marker.
 */
ClusterMarker_.prototype.show = function () {
	this.div_.style.display = "";
};

/**
 * Get whether the cluster marker is hidden.
 * @return {Boolean}
 */
ClusterMarker_.prototype.isHidden = function () {
	return this.div_.style.display === "none";
};