/* Copyright (c) 2006-2007 MetaCarta, Inc., published under the BSD license. * See http://svn.openlayers.org/trunk/openlayers/release-license.txt  * for the full text of the license. *//** * Class: OpenLayers.Icon *  * The icon represents a graphical icon on the screen.  Typically used in * conjunction with a <OpenLayers.Marker> to represent markers on a screen. * * An icon has a url, size and position.  It also contains an offset which  * allows the center point to be represented correctly.  This can be * provided either as a fixed offset or a function provided to calculate * the desired offset.  *  */OpenLayers.Icon = OpenLayers.Class({        /**      * Property: url      * {String}  image url     */    url: null,        /**      * Property: size      * {<OpenLayers.Size>}      */    size: null,    /**      * Property: offset      * {<OpenLayers.Pixel>} distance in pixels to offset the image when being rendered     */    offset: null,            /**      * Property: calculateOffset      * {<OpenLayers.Pixel>} Function to calculate the offset (based on the size)      */    calculateOffset: null,            /**      * Property: imageDiv      * {DOMElement}      */    imageDiv: null,    /**      * Property: px      * {<OpenLayers.Pixel>}      */    px: null,        /**      * Constructor: OpenLayers.Icon     * Creates an icon, which is an image tag in a div.       *     * url - {String}      * size - {<OpenLayers.Size>}      * calculateOffset - {Function}      */    initialize: function(url, size, offset, calculateOffset) {        this.url = url;        this.size = (size) ? size : new OpenLayers.Size(20,20);        this.offset = offset ? offset : new OpenLayers.Pixel(-(this.size.w/2), -(this.size.h/2));        this.calculateOffset = calculateOffset;        var id = OpenLayers.Util.createUniqueID("OL_Icon_");        this.imageDiv = OpenLayers.Util.createAlphaImageDiv(id);    },        /**      * Method: destroy     * Nullify references and remove event listeners to prevent circular      * references and memory leaks     */    destroy: function() {        OpenLayers.Event.stopObservingElement(this.imageDiv.firstChild);         this.imageDiv.innerHTML = "";        this.imageDiv = null;    },    /**      * Method: clone     *      * Returns:     * {<OpenLayers.Icon>} A fresh copy of the icon.     */    clone: function() {        return new OpenLayers.Icon(this.url,                                    this.size,                                    this.offset,                                    this.calculateOffset);    },        /**     * Method: setSize     *      * size - {<OpenLayers.Size>}      */    setSize: function(size) {        if (size != null) {            this.size = size;        }        this.draw();    },    /**      * Method: draw     * Move the div to the given pixel.     *      * Parameters:     * px - {<OpenLayers.Pixel>}      *      * Returns:     * {DOMElement} A new DOM Image of this icon set at the location passed-in     */    draw: function(px) {        OpenLayers.Util.modifyAlphaImageDiv(this.imageDiv,                                             null,                                             null,                                             this.size,                                             this.url,                                             "absolute");        this.moveTo(px);        return this.imageDiv;    },         /**      * Method: setOpacity     * Change the icon's opacity     *     * Parameters:     * opacity - {float}      */    setOpacity: function(opacity) {        OpenLayers.Util.modifyAlphaImageDiv(this.imageDiv, null, null, null,                                             null, null, null, null, opacity);    },        /**     * Method: moveTo     * move icon to passed in px.     *     * Parameters:     * px - {<OpenLayers.Pixel>}      */    moveTo: function (px) {        //if no px passed in, use stored location        if (px != null) {            this.px = px;        }        if (this.imageDiv != null) {            if (this.px == null) {                this.display(false);            } else {                if (this.calculateOffset) {                    this.offset = this.calculateOffset(this.size);                  }                var offsetPx = this.px.offset(this.offset);                OpenLayers.Util.modifyAlphaImageDiv(this.imageDiv, null, offsetPx);            }        }    },        /**      * Method: display     * Hide or show the icon     *     * Parameters:     * display - {Boolean}      */    display: function(display) {        this.imageDiv.style.display = (display) ? "" : "none";     },    CLASS_NAME: "OpenLayers.Icon"});