Merge pull request #813 from Turbo87/encoded-polyline
Format: Added EncodedPolyline class. Merging this as a first step towards support for alternative geometry encodings. See #813 for TBDs.
This commit is contained in:
ahocevar
@@ -306,6 +306,7 @@
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"OpenLayers/Format/GML/v2.js",
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"OpenLayers/Format/GML/v3.js",
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"OpenLayers/Format/Atom.js",
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"OpenLayers/Format/EncodedPolyline.js",
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"OpenLayers/Format/KML.js",
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"OpenLayers/Format/GeoRSS.js",
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"OpenLayers/Format/WFS.js",
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254
lib/OpenLayers/Format/EncodedPolyline.js
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254
lib/OpenLayers/Format/EncodedPolyline.js
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@@ -0,0 +1,254 @@
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/* Copyright (c) 2006-2012 by OpenLayers Contributors (see authors.txt for
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* full list of contributors). Published under the 2-clause BSD license.
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* See license.txt in the OpenLayers distribution or repository for the
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* full text of the license. */
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/**
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* @requires OpenLayers/Format.js
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* @requires OpenLayers/Feature/Vector.js
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*/
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/**
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* Class: OpenLayers.Format.EncodedPolyline
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* Class for reading and writing encoded polylines. Create a new instance
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* with the <OpenLayers.Format.EncodedPolyline> constructor.
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*
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* Inherits from:
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* - <OpenLayers.Format>
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*/
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OpenLayers.Format.EncodedPolyline = OpenLayers.Class(OpenLayers.Format, {
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/**
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* APIProperty: geometryType
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* {String} Geometry type to output. One of: linestring (default),
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* linearring, point, multipoint or polygon. If the geometryType is
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* point, only the first point of the string is returned.
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*/
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geometryType: "linestring",
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/**
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* Constructor: OpenLayers.Format.EncodedPolyline
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* Create a new parser for encoded polylines
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*
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* Parameters:
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* options - {Object} An optional object whose properties will be set on
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* this instance
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*
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* Returns:
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* {<OpenLayers.Format.EncodedPolyline>} A new encoded polylines parser.
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*/
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initialize: function(options) {
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OpenLayers.Format.prototype.initialize.apply(this, [options]);
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},
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/**
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* APIMethod: read
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* Deserialize an encoded polyline string and return a vector feature.
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*
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* Parameters:
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* encoded - {String} An encoded polyline string
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*
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* Returns:
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* {<OpenLayers.Feature.Vector>} A vector feature with a linestring.
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*/
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read: function(encoded) {
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var geomType;
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if (this.geometryType == "linestring")
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geomType = OpenLayers.Geometry.LineString;
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else if (this.geometryType == "linearring")
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geomType = OpenLayers.Geometry.LinearRing;
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else if (this.geometryType == "multipoint")
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geomType = OpenLayers.Geometry.MultiPoint;
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else if (this.geometryType != "point" && this.geometryType != "polygon")
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return null;
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var points = this.decode(encoded, 2);
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var pointGeometries = new Array();
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for (i in points) {
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var point = points[i];
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pointGeometries.push(
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new OpenLayers.Geometry.Point(point[1] * 1e-5, point[0] * 1e-5)
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);
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}
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if (this.geometryType == "point")
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return new OpenLayers.Feature.Vector(
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pointGeometries[0]
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);
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if (this.geometryType == "polygon")
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return new OpenLayers.Feature.Vector(
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new OpenLayers.Geometry.Polygon([
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new OpenLayers.Geometry.LinearRing(pointGeometries)
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])
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);
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return new OpenLayers.Feature.Vector(
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new geomType(pointGeometries)
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);
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},
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/**
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* APIMethod: decode
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* Deserialize an encoded string and return an array of n-dimensional
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* points.
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*
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* Parameters:
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* encoded - {String} An encoded string
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* dims - {int} The dimension of the points that are returned
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*
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* Returns:
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* {Array(Array(int))} An array containing n-dimensional arrays of
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* coordinates.
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*/
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decode: function(encoded, dims) {
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var points = new Array();
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var point = new Array(dims);
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// Reset the point array
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for (var i = 0; i < point.length; ++i)
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point[i] = 0;
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for (var i = 0; i < encoded.length;) {
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for (var dim = 0; dim < dims; ++dim) {
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var result = 0;
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var shift = 0;
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var b;
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do {
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b = encoded.charCodeAt(i++) - 63;
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result |= (b & 0x1f) << shift;
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shift += 5;
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} while (b >= 0x20);
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point[dim] += ((result & 1) ? ~(result >> 1) : (result >> 1));
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}
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points.push(point.slice(0));
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}
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return points;
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},
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/**
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* APIMethod: write
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* Serialize a feature or array of features into a WKT string.
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*
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* Parameters:
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* features - {<OpenLayers.Feature.Vector>|Array} A feature or array of
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* features
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*
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* Returns:
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* {String} The WKT string representation of the input geometries
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*/
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write: function(features) {
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var feature;
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if (features.constructor == Array)
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feature = features[0];
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else
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feature = features;
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var geometry = feature.geometry;
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var type = geometry.CLASS_NAME.split('.')[2].toLowerCase();
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var pointGeometries;
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if (type == "point")
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pointGeometries = new Array(geometry);
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else if (type == "linestring" ||
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type == "linearring" ||
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type == "multipoint")
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pointGeometries = geometry.components;
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else if (type == "polygon")
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pointGeometries = geometry.components[0].components;
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else
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return null;
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var points = new Array();
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for (var i in pointGeometries) {
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var pointGeometry = pointGeometries[i];
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var point = [Math.round(pointGeometry.y * 1e5),
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Math.round(pointGeometry.x * 1e5)];
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points.push(point);
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}
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var result = this.encode(points, 2);
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return result;
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},
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/**
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* APIMethod: encode
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* Serialize an array of n-dimensional points and return an encoded string
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*
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* Parameters:
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* points - {Array(Array(int))} An array containing n-dimensional
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* arrays of coordinates
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* dims - {int} The dimension of the points that should be read
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*
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* Returns:
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* {String} An encoded string
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*/
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encode: function (points, dims) {
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var encoded_points = "";
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var lastPoint = new Array(dims);
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for (var i = 0; i < lastPoint.length; ++i)
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lastPoint[i] = 0;
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for (var i = 0; i < points.length; i++) {
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var point = points[i];
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for (var dim = 0; dim < lastPoint.length; ++dim) {
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var delta = point[dim] - lastPoint[dim];
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encoded_points += this.encodeSignedNumber(delta);
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}
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lastPoint = point;
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}
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return encoded_points;
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},
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/**
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* Method: encodeSignedNumber
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* Encode one single signed integer and return an encoded string
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*
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* Parameters:
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* num - {int} A signed integer that should be encoded
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*
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* Returns:
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* {String} An encoded string
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*/
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encodeSignedNumber: function (num) {
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var sgn_num = num << 1;
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if (num < 0)
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sgn_num = ~(sgn_num);
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return this.encodeNumber(sgn_num);
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},
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/**
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* Method: encodeNumber
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* Encode one single unsigned integer and return an encoded string
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*
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* encodeSignedNumber should be used instead of using this method directly!
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*
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* Parameters:
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* num - {int} An unsigned integer that should be encoded
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*
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* Returns:
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* {String} An encoded string
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*/
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encodeNumber: function (num) {
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var encodeString = "";
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var value;
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while (num >= 0x20) {
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value = (0x20 | (num & 0x1f)) + 63;
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encodeString += (String.fromCharCode(value));
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num >>= 5;
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}
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value = num + 63;
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encodeString += (String.fromCharCode(value));
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return encodeString;
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},
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CLASS_NAME: "OpenLayers.Format.EncodedPolyline"
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});
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