Files
openlayers/lib/OpenLayers/Tile.js
2006-11-15 18:43:34 +00:00

125 lines
3.4 KiB
JavaScript

/* Copyright (c) 2006 MetaCarta, Inc., published under a modified BSD license.
* See http://svn.openlayers.org/trunk/openlayers/release-license.txt
* for the full text of the license. */
/*
* @class
*
* This is a class designed to designate a single tile, however
* it is explicitly designed to do relatively little. Tiles store information
* about themselves -- such as the URL that they are related to, and their
* size - but do not add themselves to the layer div automatically, for
* example.
*/
OpenLayers.Tile = OpenLayers.Class.create();
OpenLayers.Tile.prototype = {
/** @type String */
id: null,
/** @type OpenLayers.Layer */
layer: null,
/** @type String url of the request */
url:null,
/** @type OpenLayers.Bounds */
bounds:null,
/** @type OpenLayers.Size */
size:null,
/** Top Left pixel of the tile
* @type OpenLayers.Pixel */
position:null,
/** @type Boolean */
drawn: false,
/**
* @constructor
*
* @param {OpenLayers.Layer} layer
* @param {OpenLayers.Pixel} position
* @param {OpenLayers.Bounds} bounds
* @param {String} url
* @param {OpenLayers.Size} size
*/
initialize: function(layer, position, bounds, url, size) {
this.layer = layer;
this.position = position;
this.bounds = bounds;
this.url = url;
this.size = size;
//give the tile a unique id based on its BBOX.
this.id = OpenLayers.Util.createUniqueID("Tile_");
},
/** nullify references to prevent circular references and memory leaks
*/
destroy:function() {
this.layer = null;
this.bounds = null;
this.size = null;
this.position = null;
},
/**
*/
draw:function() {
this.drawn = true;
},
/**
* @param {OpenLayers.Bounds}
* @param {OpenLayers.pixel} position
* @param {Boolean} redraw Redraw tile after moving?
* Default is true
*/
moveTo: function (bounds, position, redraw) {
if (redraw == null) {
redraw = true;
}
this.clear();
this.bounds = bounds.clone();
this.position = position.clone();
if (redraw) {
this.draw();
}
},
/** Clear the tile of any bounds/position-related data so that it can
* be reused in a new location.
*/
clear: function() {
this.drawn = false;
},
getBoundsFromBaseLayer: function(position) {
var topLeft = this.layer.map.getLonLatFromLayerPx(this.position);
var bottomRightPx = this.position.clone();
bottomRightPx.x += this.size.w;
bottomRightPx.y += this.size.h;
var bottomRight = this.layer.map.getLonLatFromLayerPx(bottomRightPx);
// Handle the case where the base layer wraps around the date line.
// Google does this, and it breaks WMS servers to request bounds in that fashion.
if (topLeft.lon > bottomRight.lon) {
if (topLeft.lon < 0) {
topLeft.lon = -180 - (topLeft.lon+180);
} else {
bottomRight.lon = 180+bottomRight.lon+180;
}
}
bounds = new OpenLayers.Bounds(topLeft.lon, bottomRight.lat, bottomRight.lon, topLeft.lat);
return bounds;
},
/** @final @type String */
CLASS_NAME: "OpenLayers.Tile"
};