--- a/labs/openlayers/lib/OpenLayers/Control/Measure.js +++ b/labs/openlayers/lib/OpenLayers/Control/Measure.js @@ -1,1 +1,322 @@ - +/* 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 + * @requires OpenLayers/Feature/Vector.js + */ + +/** + * Class: OpenLayers.Control.Measure + * Allows for drawing of features for measurements. + * + * Inherits from: + * - <OpenLayers.Control> + */ +OpenLayers.Control.Measure = OpenLayers.Class(OpenLayers.Control, { + + /** + * Constant: EVENT_TYPES + * {Array(String)} Supported application event types. Register a listener + * for a particular event with the following syntax: + * (code) + * control.events.register(type, obj, listener); + * (end) + * + * Listeners will be called with a reference to an event object. The + * properties of this event depends on exactly what happened. + * + * Supported control event types (in addition to those from <OpenLayers.Control>): + * measure - Triggered when a measurement sketch is complete. Listeners + * will receive an event with measure, units, order, and geometry + * properties. + * measurepartial - Triggered when a new point is added to the + * measurement sketch. Listeners receive an event with measure, + * units, order, and geometry. + */ + EVENT_TYPES: ['measure', 'measurepartial'], + + /** + * APIProperty: handlerOptions + * {Object} Used to set non-default properties on the control's handler + */ + handlerOptions: null, + + /** + * Property: callbacks + * {Object} The functions that are sent to the handler for callback + */ + callbacks: null, + + /** + * Property: displaySystem + * {String} Display system for output measurements. Supported values + * are 'english', 'metric', and 'geographic'. Default is 'metric'. + */ + displaySystem: 'metric', + + /** + * Property: geodesic + * {Boolean} Calculate geodesic metrics instead of planar metrics. This + * requires that geometries can be transformed into Geographic/WGS84 + * (if that is not already the map projection). Default is false. + */ + geodesic: false, + + /** + * Property: displaySystemUnits + * {Object} Units for various measurement systems. Values are arrays + * of unit abbreviations (from OpenLayers.INCHES_PER_UNIT) in decreasing + * order of length. + */ + displaySystemUnits: { + geographic: ['dd'], + english: ['mi', 'ft', 'in'], + metric: ['km', 'm'] + }, + + /** + * Property: delay + * {Number} Number of milliseconds between clicks before the event is + * considered a double-click. The "measurepartial" event will not + * be triggered if the sketch is completed within this time. This + * is required for IE where creating a browser reflow (if a listener + * is modifying the DOM by displaying the measurement values) messes + * with the dblclick listener in the sketch handler. + */ + partialDelay: 300, + + /** + * Property: delayedTrigger + * {Number} Timeout id of trigger for measurepartial. + */ + delayedTrigger: null, + + /** + * APIProperty: persist + * {Boolean} Keep the temporary measurement sketch drawn after the + * measurement is complete. The geometry will persist until a new + * measurement is started, the control is deactivated, or <cancel> is + * called. + */ + persist: false, + + /** + * Constructor: OpenLayers.Control.Measure + * + * Parameters: + * handler - {<OpenLayers.Handler>} + * options - {Object} + */ + initialize: function(handler, options) { + // concatenate events specific to measure with those from the base + this.EVENT_TYPES = + OpenLayers.Control.Measure.prototype.EVENT_TYPES.concat( + OpenLayers.Control.prototype.EVENT_TYPES + ); + OpenLayers.Control.prototype.initialize.apply(this, [options]); + this.callbacks = OpenLayers.Util.extend( + {done: this.measureComplete, point: this.measurePartial}, + this.callbacks + ); + + // let the handler options override, so old code that passes 'persist' + // directly to the handler does not need an update + this.handlerOptions = OpenLayers.Util.extend( + {persist: this.persist}, this.handlerOptions + ); + this.handler = new handler(this, this.callbacks, this.handlerOptions); + }, + + /** + * APIMethod: cancel + * Stop the control from measuring. If <persist> is true, the temporary + * sketch will be erased. + */ + cancel: function() { + this.handler.cancel(); + }, + + /** + * Method: updateHandler + * + * Parameters: + * handler - {Function} One of the sketch handler constructors. + * options - {Object} Options for the handler. + */ + updateHandler: function(handler, options) { + var active = this.active; + if(active) { + this.deactivate(); + } + this.handler = new handler(this, this.callbacks, options); + if(active) { + this.activate(); + } + }, + + /** + * Method: measureComplete + * Called when the measurement sketch is done. + * + * Parameters: + * geometry - {<OpenLayers.Geometry>} + */ + measureComplete: function(geometry) { + if(this.delayedTrigger) { + window.clearTimeout(this.delayedTrigger); + } + this.measure(geometry, "measure"); + }, + + /** + * Method: measurePartial + * Called each time a new point is added to the measurement sketch. + * + * Parameters: + * point - {<OpenLayers.Geometry.Point>} The last point added. + * geometry - {<OpenLayers.Geometry>} The sketch geometry. + */ + measurePartial: function(point, geometry) { + if (geometry.getLength() > 0) { + geometry = geometry.clone(); + this.delayedTrigger = window.setTimeout( + OpenLayers.Function.bind(function() { + this.measure(geometry, "measurepartial"); + }, this), + this.partialDelay + ); + } + }, + + /** + * Method: measure + * + * Parameters: + * geometry - {<OpenLayers.Geometry>} + * eventType - {String} + */ + measure: function(geometry, eventType) { + var stat, order; + if(geometry.CLASS_NAME.indexOf('LineString') > -1) { + stat = this.getBestLength(geometry); + order = 1; + } else { + stat = this.getBestArea(geometry); + order = 2; + } + this.events.triggerEvent(eventType, { + measure: stat[0], + units: stat[1], + order: order, + geometry: geometry + }); + }, + + /** + * Method: getBestArea + * Based on the <displaySystem> returns the area of a geometry. + * + * Parameters: + * geometry - {<OpenLayers.Geometry>} + * + * Returns: + * {Array([Float, String])} Returns a two item array containing the + * area and the units abbreviation. + */ + getBestArea: function(geometry) { + var units = this.displaySystemUnits[this.displaySystem]; + var unit, area; + for(var i=0, len=units.length; i<len; ++i) { + unit = units[i]; + area = this.getArea(geometry, unit); + if(area > 1) { + break; + } + } + return [area, unit]; + }, + + /** + * Method: getArea + * + * Parameters: + * geometry - {<OpenLayers.Geometry>} + * units - {String} Unit abbreviation + * + * Returns: + * {Float} The geometry area in the given units. + */ + getArea: function(geometry, units) { + var area, geomUnits; + if(this.geodesic) { + area = geometry.getGeodesicArea(this.map.getProjectionObject()); + geomUnits = "m"; + } else { + area = geometry.getArea(); + geomUnits = this.map.getUnits(); + } + var inPerDisplayUnit = OpenLayers.INCHES_PER_UNIT[units]; + if(inPerDisplayUnit) { + var inPerMapUnit = OpenLayers.INCHES_PER_UNIT[geomUnits]; + area *= Math.pow((inPerMapUnit / inPerDisplayUnit), 2); + } + return area; + }, + + /** + * Method: getBestLength + * Based on the <displaySystem> returns the length of a geometry. + * + * Parameters: + * geometry - {<OpenLayers.Geometry>} + * + * Returns: + * {Array([Float, String])} Returns a two item array containing the + * length and the units abbreviation. + */ + getBestLength: function(geometry) { + var units = this.displaySystemUnits[this.displaySystem]; + var unit, length; + for(var i=0, len=units.length; i<len; ++i) { + unit = units[i]; + length = this.getLength(geometry, unit); + if(length > 1) { + break; + } + } + return [length, unit]; + }, + + /** + * Method: getLength + * + * Parameters: + * geometry - {<OpenLayers.Geometry>} + * units - {String} Unit abbreviation + * + * Returns: + * {Float} The geometry length in the given units. + */ + getLength: function(geometry, units) { + var length, geomUnits; + if(this.geodesic) { + length = geometry.getGeodesicLength(this.map.getProjectionObject()); + geomUnits = "m"; + } else { + length = geometry.getLength(); + geomUnits = this.map.getUnits(); + } + var inPerDisplayUnit = OpenLayers.INCHES_PER_UNIT[units]; + if(inPerDisplayUnit) { + var inPerMapUnit = OpenLayers.INCHES_PER_UNIT[geomUnits]; + length *= (inPerMapUnit / inPerDisplayUnit); + } + return length; + }, + + CLASS_NAME: "OpenLayers.Control.Measure" +}); +