Files
openlayers/src/ol/geom/sharedvertices.js
2013-04-08 13:25:01 +02:00

163 lines
3.9 KiB
JavaScript

goog.provide('ol.geom.SharedVertices');
goog.require('goog.asserts');
goog.require('ol.geom.Vertex');
goog.require('ol.geom.VertexArray');
/**
* @typedef {{dimension: (number),
* offset: (ol.geom.Vertex|undefined)}}
*/
ol.geom.SharedVerticesOptions;
/**
* Provides methods for dealing with shared, flattened arrays of vertices.
*
* @constructor
* @param {ol.geom.SharedVerticesOptions=} opt_options Shared vertices options.
*/
ol.geom.SharedVertices = function(opt_options) {
var options = opt_options ? opt_options : {};
/**
* @type {Array.<number>}
*/
this.coordinates = [];
/**
* @type {Array.<number>}
* @private
*/
this.starts_ = [];
/**
* @type {Array.<number>}
* @private
*/
this.counts_ = [];
/**
* Number of dimensions per vertex. Default is 2.
* @type {number}
* @private
*/
this.dimension_ = options.dimension || 2;
/**
* Vertex offset.
* @type {Array.<number>}
* @private
*/
this.offset_ = options.offset || null;
goog.asserts.assert(goog.isNull(this.offset_) ||
this.offset_.length === this.dimension_);
};
/**
* Adds a vertex array to the shared coordinate array.
* @param {ol.geom.VertexArray} vertices Array of vertices.
* @return {number} Index used to reference the added vertex array.
*/
ol.geom.SharedVertices.prototype.add = function(vertices) {
var start = this.coordinates.length;
var offset = this.offset_;
var dimension = this.dimension_;
var count = vertices.length;
var vertex, index;
for (var i = 0; i < count; ++i) {
vertex = vertices[i];
goog.asserts.assert(vertex.length == dimension);
if (!offset) {
Array.prototype.push.apply(this.coordinates, vertex);
} else {
index = start + (i * dimension);
for (var j = 0; j < dimension; ++j) {
this.coordinates[index + j] = vertex[j] - offset[j];
}
}
}
var length = this.starts_.push(start);
this.counts_.push(count);
return length - 1;
};
/**
* @param {number} id The vertex array identifier (returned by add).
* @param {number} index The vertex index.
* @param {number} dim The coordinate dimension.
* @return {number} The coordinate value.
*/
ol.geom.SharedVertices.prototype.get = function(id, index, dim) {
goog.asserts.assert(id < this.starts_.length);
goog.asserts.assert(dim <= this.dimension_);
goog.asserts.assert(index < this.counts_[id]);
var start = this.starts_[id];
var value = this.coordinates[start + (index * this.dimension_) + dim];
if (this.offset_) {
value += this.offset_[dim];
}
return value;
};
/**
* @param {number} id The vertex array identifier (returned by add).
* @return {number} The number of vertices in the referenced array.
*/
ol.geom.SharedVertices.prototype.getCount = function(id) {
goog.asserts.assert(id < this.counts_.length);
return this.counts_[id];
};
/**
* Get the array of counts. The index returned by the add method can be used
* to look up the number of vertices.
*
* @return {Array.<number>} The counts array.
*/
ol.geom.SharedVertices.prototype.getCounts = function() {
return this.counts_;
};
/**
* @return {number} The dimension of each vertex in the array.
*/
ol.geom.SharedVertices.prototype.getDimension = function() {
return this.dimension_;
};
/**
* @return {Array.<number>} The offset array for vertex coordinates (or null).
*/
ol.geom.SharedVertices.prototype.getOffset = function() {
return this.offset_;
};
/**
* @param {number} id The vertex array identifier (returned by add).
* @return {number} The start index in the shared vertices array.
*/
ol.geom.SharedVertices.prototype.getStart = function(id) {
goog.asserts.assert(id < this.starts_.length);
return this.starts_[id];
};
/**
* Get the array of start indexes.
* @return {Array.<number>} The starts array.
*/
ol.geom.SharedVertices.prototype.getStarts = function() {
return this.starts_;
};