| /* 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" | |
| }); | |