More trip planner testing with colors
[busui.git] / labs / openlayers / lib / OpenLayers / Projection.js
blob:a/labs/openlayers/lib/OpenLayers/Projection.js -> blob:b/labs/openlayers/lib/OpenLayers/Projection.js
--- a/labs/openlayers/lib/OpenLayers/Projection.js
+++ b/labs/openlayers/lib/OpenLayers/Projection.js
@@ -1,1 +1,179 @@
+/* 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/Util.js
+ */
+
+/**
+ * Class: OpenLayers.Projection
+ * Class for coordinate transforms between coordinate systems.
+ *     Depends on the proj4js library. If proj4js is not available, 
+ *     then this is just an empty stub.
+ */
+OpenLayers.Projection = OpenLayers.Class({
+
+    /**
+     * Property: proj
+     * {Object} Proj4js.Proj instance.
+     */
+    proj: null,
+    
+    /**
+     * Property: projCode
+     * {String}
+     */
+    projCode: null,
+
+    /**
+     * Constructor: OpenLayers.Projection
+     * This class offers several methods for interacting with a wrapped 
+     *     pro4js projection object. 
+     *
+     * Parameters:
+     * projCode - {String} A string identifying the Well Known Identifier for
+     *    the projection.
+     * options - {Object} An optional object to set additional properties
+     *     on the layer.
+     *
+     * Returns:
+     * {<OpenLayers.Projection>} A projection object.
+     */
+    initialize: function(projCode, options) {
+        OpenLayers.Util.extend(this, options);
+        this.projCode = projCode;
+        if (window.Proj4js) {
+            this.proj = new Proj4js.Proj(projCode);
+        }
+    },
+    
+    /**
+     * APIMethod: getCode
+     * Get the string SRS code.
+     *
+     * Returns:
+     * {String} The SRS code.
+     */
+    getCode: function() {
+        return this.proj ? this.proj.srsCode : this.projCode;
+    },
+   
+    /**
+     * APIMethod: getUnits
+     * Get the units string for the projection -- returns null if 
+     *     proj4js is not available.
+     *
+     * Returns:
+     * {String} The units abbreviation.
+     */
+    getUnits: function() {
+        return this.proj ? this.proj.units : null;
+    },
+
+    /**
+     * Method: toString
+     * Convert projection to string (getCode wrapper).
+     *
+     * Returns:
+     * {String} The projection code.
+     */
+    toString: function() {
+        return this.getCode();
+    },
+
+    /**
+     * Method: equals
+     * Test equality of two projection instances.  Determines equality based
+     *     soley on the projection code.
+     *
+     * Returns:
+     * {Boolean} The two projections are equivalent.
+     */
+    equals: function(projection) {
+        if (projection && projection.getCode) {
+            return this.getCode() == projection.getCode();
+        } else {
+            return false;
+        }    
+    },
+
+    /* Method: destroy
+     * Destroy projection object.
+     */
+    destroy: function() {
+        delete this.proj;
+        delete this.projCode;
+    },
+    
+    CLASS_NAME: "OpenLayers.Projection" 
+});     
+
+/**
+ * Property: transforms
+ * Transforms is an object, with from properties, each of which may
+ * have a to property. This allows you to define projections without 
+ * requiring support for proj4js to be included.
+ *
+ * This object has keys which correspond to a 'source' projection object.  The
+ * keys should be strings, corresponding to the projection.getCode() value.
+ * Each source projection object should have a set of destination projection
+ * keys included in the object. 
+ * 
+ * Each value in the destination object should be a transformation function,
+ * where the function is expected to be passed an object with a .x and a .y
+ * property.  The function should return the object, with the .x and .y
+ * transformed according to the transformation function.
+ *
+ * Note - Properties on this object should not be set directly.  To add a
+ *     transform method to this object, use the <addTransform> method.  For an
+ *     example of usage, see the OpenLayers.Layer.SphericalMercator file.
+ */
+OpenLayers.Projection.transforms = {};
+
+/**
+ * APIMethod: addTransform
+ * Set a custom transform method between two projections.  Use this method in
+ *     cases where the proj4js lib is not available or where custom projections
+ *     need to be handled.
+ *
+ * Parameters:
+ * from - {String} The code for the source projection
+ * to - {String} the code for the destination projection
+ * method - {Function} A function that takes a point as an argument and
+ *     transforms that point from the source to the destination projection
+ *     in place.  The original point should be modified.
+ */
+OpenLayers.Projection.addTransform = function(from, to, method) {
+    if(!OpenLayers.Projection.transforms[from]) {
+        OpenLayers.Projection.transforms[from] = {};
+    }
+    OpenLayers.Projection.transforms[from][to] = method;
+};
+
+/**
+ * APIMethod: transform
+ * Transform a point coordinate from one projection to another.  Note that
+ *     the input point is transformed in place.
+ * 
+ * Parameters:
+ * point - {{OpenLayers.Geometry.Point> | Object} An object with x and y
+ *     properties representing coordinates in those dimensions.
+ * sourceProj - {OpenLayers.Projection} Source map coordinate system
+ * destProj - {OpenLayers.Projection} Destination map coordinate system
+ *
+ * Returns:
+ * point - {object} A transformed coordinate.  The original point is modified.
+ */
+OpenLayers.Projection.transform = function(point, source, dest) {
+    if (source.proj && dest.proj) {
+        point = Proj4js.transform(source.proj, dest.proj, point);
+    } else if (source && dest && 
+               OpenLayers.Projection.transforms[source.getCode()] && 
+               OpenLayers.Projection.transforms[source.getCode()][dest.getCode()]) {
+        OpenLayers.Projection.transforms[source.getCode()][dest.getCode()](point); 
+    }
+    return point;
+};
+