--- a/labs/openlayers/lib/OpenLayers/Control/ScaleLine.js +++ b/labs/openlayers/lib/OpenLayers/Control/ScaleLine.js @@ -1,1 +1,224 @@ - +/* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for + * full list of contributors). Published under the Clear BSD license. + * See http://svn.openlayers.org/trunk/openlayers/license.txt for the + * full text of the license. */ + +/** + * @requires OpenLayers/Control.js + */ + +/** + * Class: OpenLayers.Control.ScaleLine + * The ScaleLine displays a small line indicator representing the current + * map scale on the map. By default it is drawn in the lower left corner of + * the map. + * + * Inherits from: + * - <OpenLayers.Control> + * + * Is a very close copy of: + * - <OpenLayers.Control.Scale> + */ +OpenLayers.Control.ScaleLine = OpenLayers.Class(OpenLayers.Control, { + + /** + * Property: maxWidth + * {Integer} Maximum width of the scale line in pixels. Default is 100. + */ + maxWidth: 100, + + /** + * Property: topOutUnits + * {String} Units for zoomed out on top bar. Default is km. + */ + topOutUnits: "km", + + /** + * Property: topInUnits + * {String} Units for zoomed in on top bar. Default is m. + */ + topInUnits: "m", + + /** + * Property: bottomOutUnits + * {String} Units for zoomed out on bottom bar. Default is mi. + */ + bottomOutUnits: "mi", + + /** + * Property: bottomInUnits + * {String} Units for zoomed in on bottom bar. Default is ft. + */ + bottomInUnits: "ft", + + /** + * Property: eTop + * {DOMElement} + */ + eTop: null, + + /** + * Property: eBottom + * {DOMElement} + */ + eBottom:null, + + /** + * APIProperty: geodesic + * {Boolean} Use geodesic measurement. Default is false. The recommended + * setting for maps in EPSG:4326 is false, and true EPSG:900913. If set to + * true, the scale will be calculated based on the horizontal size of the + * pixel in the center of the map viewport. + */ + geodesic: false, + + /** + * Constructor: OpenLayers.Control.ScaleLine + * Create a new scale line control. + * + * Parameters: + * options - {Object} An optional object whose properties will be used + * to extend the control. + */ + initialize: function(options) { + OpenLayers.Control.prototype.initialize.apply(this, [options]); + }, + + /** + * Method: draw + * + * Returns: + * {DOMElement} + */ + draw: function() { + OpenLayers.Control.prototype.draw.apply(this, arguments); + if (!this.eTop) { + // stick in the top bar + this.eTop = document.createElement("div"); + this.eTop.className = this.displayClass + "Top"; + var theLen = this.topInUnits.length; + this.div.appendChild(this.eTop); + if((this.topOutUnits == "") || (this.topInUnits == "")) { + this.eTop.style.visibility = "hidden"; + } else { + this.eTop.style.visibility = "visible"; + } + + // and the bottom bar + this.eBottom = document.createElement("div"); + this.eBottom.className = this.displayClass + "Bottom"; + this.div.appendChild(this.eBottom); + if((this.bottomOutUnits == "") || (this.bottomInUnits == "")) { + this.eBottom.style.visibility = "hidden"; + } else { + this.eBottom.style.visibility = "visible"; + } + } + this.map.events.register('moveend', this, this.update); + this.update(); + return this.div; + }, + + /** + * Method: getBarLen + * Given a number, round it down to the nearest 1,2,5 times a power of 10. + * That seems a fairly useful set of number groups to use. + * + * Parameters: + * maxLen - {float} the number we're rounding down from + * + * Returns: + * {Float} the rounded number (less than or equal to maxLen) + */ + getBarLen: function(maxLen) { + // nearest power of 10 lower than maxLen + var digits = parseInt(Math.log(maxLen) / Math.log(10)); + var pow10 = Math.pow(10, digits); + + // ok, find first character + var firstChar = parseInt(maxLen / pow10); + + // right, put it into the correct bracket + var barLen; + if(firstChar > 5) { + barLen = 5; + } else if(firstChar > 2) { + barLen = 2; + } else { + barLen = 1; + } + + // scale it up the correct power of 10 + return barLen * pow10; + }, + + /** + * Method: update + * Update the size of the bars, and the labels they contain. + */ + update: function() { + var res = this.map.getResolution(); + if (!res) { + return; + } + + var curMapUnits = this.map.getUnits(); + var inches = OpenLayers.INCHES_PER_UNIT; + + // convert maxWidth to map units + var maxSizeData = this.maxWidth * res * inches[curMapUnits]; + var geodesicRatio = 1; + if(this.geodesic === true) { + var maxSizeGeodesic = (this.map.getGeodesicPixelSize().w || + 0.000001) * this.maxWidth; + var maxSizeKilometers = maxSizeData / inches["km"]; + geodesicRatio = maxSizeGeodesic / maxSizeKilometers; + maxSizeData *= geodesicRatio; + } + + // decide whether to use large or small scale units + var topUnits; + var bottomUnits; + if(maxSizeData > 100000) { + topUnits = this.topOutUnits; + bottomUnits = this.bottomOutUnits; + } else { + topUnits = this.topInUnits; + bottomUnits = this.bottomInUnits; + } + + // and to map units units + var topMax = maxSizeData / inches[topUnits]; + var bottomMax = maxSizeData / inches[bottomUnits]; + + // now trim this down to useful block length + var topRounded = this.getBarLen(topMax); + var bottomRounded = this.getBarLen(bottomMax); + + // and back to display units + topMax = topRounded / inches[curMapUnits] * inches[topUnits]; + bottomMax = bottomRounded / inches[curMapUnits] * inches[bottomUnits]; + + // and to pixel units + var topPx = topMax / res / geodesicRatio; + var bottomPx = bottomMax / res / geodesicRatio; + + // now set the pixel widths + // and the values inside them + + if (this.eBottom.style.visibility == "visible"){ + this.eBottom.style.width = Math.round(bottomPx) + "px"; + this.eBottom.innerHTML = bottomRounded + " " + bottomUnits ; + } + + if (this.eTop.style.visibility == "visible"){ + this.eTop.style.width = Math.round(topPx) + "px"; + this.eTop.innerHTML = topRounded + " " + topUnits; + } + + }, + + CLASS_NAME: "OpenLayers.Control.ScaleLine" +}); + +