f582775d11
getMaxExtent(), getMaxResolution(), and getNumZoomLevels(). They were just wrapping around the properties. better to just access the property directly. Needed to update for these removals in many different files. - Improved initResolutions() functionality. It is now I believe both thorough and complete. The only exception is that we should maybe allow a way for the user to set up resolutions[] array using only minResolution and numZoomLevels instead of only maxResolution and numZoomLevels... but I'm not really sure anyone would ever really want to use that. And at any rate, I don't know the math for how to do it. I'm sure schuyler or Dr. 5 would. Oh. for a summary of how initResolutions works, see: http://trac.openlayers.org/wiki/SettingZoomLevels - Move getResolution(), initResolutions() out of HTTPRequest and into Layer. On thinking this through (and trying to write documentation), I realized that the real, true, GENERIC case for a layer will be using this awesome resolutions[] array that allows for setting number of zoom levels, default max resolutions, special scale arrays, etc. - Updated code for getZoomForExtent() to work with resolutions[] array, instead of using the the log 2 equation. - Move standard getZoomForExtent() and getExtent() out of Grid and into Layer. Like above, there is no reason for these methods to be found so far down in the food chain. They are part of the generic calculations for generic layers, so they belong in Layer. git-svn-id: http://svn.openlayers.org/trunk/openlayers@1379 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
399 lines
13 KiB
JavaScript
399 lines
13 KiB
JavaScript
/* Copyright (c) 2006 MetaCarta, Inc., published under the BSD license.
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* See http://svn.openlayers.org/trunk/openlayers/license.txt for the full
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* text of the license. */
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/**
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* @class
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*
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* @requires OpenLayers/Layer/HTTPRequest.js
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*/
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OpenLayers.Layer.Grid = Class.create();
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OpenLayers.Layer.Grid.prototype =
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Object.extend( new OpenLayers.Layer.HTTPRequest(), {
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/** @type OpenLayers.Size */
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tileSize: null,
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/** this is an array of rows, each row is an array of tiles
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*
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* @type Array(Array) */
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grid: null,
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/** @type Integer */
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buffer: 2,
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/**
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* @constructor
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*
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* @param {String} name
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* @param {String} url
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* @param {Object} params
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* @param {Object} options Hashtable of extra options to tag onto the layer
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*/
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initialize: function(name, url, params, options) {
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OpenLayers.Layer.HTTPRequest.prototype.initialize.apply(this,
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arguments);
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this.grid = new Array();
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},
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/** on destroy, clear the grid.
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*
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*/
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destroy: function() {
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this.clearGrid();
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this.grid = null;
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this.tileSize = null;
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OpenLayers.Layer.HTTPRequest.prototype.destroy.apply(this, arguments);
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},
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/**
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* @param {Object} obj
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*
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* @returns An exact clone of this OpenLayers.Layer.Grid
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* @type OpenLayers.Layer.Grid
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*/
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clone: function (obj) {
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if (obj == null) {
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obj = new OpenLayers.Layer.Grid(this.name,
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this.url,
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this.params,
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this.options);
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}
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//get all additions from superclasses
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obj = OpenLayers.Layer.HTTPRequest.prototype.clone.apply(this, [obj]);
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// copy/set any non-init, non-simple values here
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if (this.tileSize != null) {
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obj.tileSize = this.tileSize.clone();
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}
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// we do not want to copy reference to grid. that should stay at null
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obj.grid = null;
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return obj;
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},
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/** When the layer is added to a map, then we can ask the map for
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* its default tile size
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*
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* @param {OpenLayers.Map} map
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*/
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setMap: function(map) {
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OpenLayers.Layer.HTTPRequest.prototype.setMap.apply(this, arguments);
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if (this.tileSize == null) {
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this.tileSize = this.map.getTileSize();
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}
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},
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/** This function is called whenever the map is moved. All the moving
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* of actual 'tiles' is done by the map, but moveTo's role is to accept
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* a bounds and make sure the data that that bounds requires is pre-loaded.
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*
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* @param {OpenLayers.Bounds} bounds
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* @param {Boolean} zoomChanged
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* @param {Boolean} dragging
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*/
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moveTo:function(bounds, zoomChanged, dragging) {
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if (bounds == null) {
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bounds = this.map.getExtent();
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}
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if (bounds != null) {
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if (!this.grid.length || zoomChanged
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|| !this.getGridBounds().containsBounds(bounds, true)) {
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this._initTiles();
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} else {
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while (true) {
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var tlLayer = this.grid[0][0].position;
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var tlViewPort =
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this.map.getViewPortPxFromLayerPx(tlLayer);
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if (tlViewPort.x > -this.tileSize.w * (this.buffer - 1)) {
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this.shiftColumn(true);
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} else if (tlViewPort.x < -this.tileSize.w * this.buffer) {
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this.shiftColumn(false);
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} else if (tlViewPort.y > -this.tileSize.h * (this.buffer - 1)) {
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this.shiftRow(true);
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} else if (tlViewPort.y < -this.tileSize.h * this.buffer) {
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this.shiftRow(false);
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} else {
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break;
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}
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}
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}
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}
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},
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/**
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* @private
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*
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* @returns A Bounds object representing the bounds of all the currently
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* loaded tiles (including those partially or not at all seen
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* onscreen)
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* @type OpenLayers.Bounds
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*/
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getGridBounds:function() {
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var bottom = this.grid.length - 1;
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var bottomLeftTile = this.grid[bottom][0];
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var right = this.grid[0].length - 1;
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var topRightTile = this.grid[0][right];
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return new OpenLayers.Bounds(bottomLeftTile.bounds.left,
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bottomLeftTile.bounds.bottom,
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topRightTile.bounds.right,
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topRightTile.bounds.top);
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},
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/**
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* @private
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*/
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_initTiles:function() {
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var viewSize = this.map.getSize();
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var bounds = this.map.getExtent();
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var extent = this.map.getMaxExtent();
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var resolution = this.map.getResolution();
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var tilelon = resolution * this.tileSize.w;
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var tilelat = resolution * this.tileSize.h;
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var offsetlon = bounds.left - extent.left;
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var tilecol = Math.floor(offsetlon/tilelon) - this.buffer;
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var tilecolremain = offsetlon/tilelon - tilecol;
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var tileoffsetx = -tilecolremain * this.tileSize.w;
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var tileoffsetlon = extent.left + tilecol * tilelon;
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var offsetlat = bounds.top - (extent.bottom + tilelat);
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var tilerow = Math.ceil(offsetlat/tilelat) + this.buffer;
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var tilerowremain = tilerow - offsetlat/tilelat;
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var tileoffsety = -tilerowremain * this.tileSize.h;
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var tileoffsetlat = extent.bottom + tilerow * tilelat;
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tileoffsetx = Math.round(tileoffsetx); // heaven help us
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tileoffsety = Math.round(tileoffsety);
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this.origin = new OpenLayers.Pixel(tileoffsetx, tileoffsety);
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var startX = tileoffsetx;
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var startLon = tileoffsetlon;
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var rowidx = 0;
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do {
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var row = this.grid[rowidx++];
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if (!row) {
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row = new Array();
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this.grid.push(row);
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}
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tileoffsetlon = startLon;
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tileoffsetx = startX;
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var colidx = 0;
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do {
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var tileBounds = new OpenLayers.Bounds(tileoffsetlon,
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tileoffsetlat,
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tileoffsetlon + tilelon,
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tileoffsetlat + tilelat);
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var x = tileoffsetx;
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x -= parseInt(this.map.layerContainerDiv.style.left);
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var y = tileoffsety;
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y -= parseInt(this.map.layerContainerDiv.style.top);
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var px = new OpenLayers.Pixel(x, y);
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var tile = row[colidx++];
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if (!tile) {
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tile = this.addTile(tileBounds, px);
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row.push(tile);
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} else {
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tile.moveTo(tileBounds, px, false);
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}
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tileoffsetlon += tilelon;
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tileoffsetx += this.tileSize.w;
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} while (tileoffsetlon <= bounds.right + tilelon * this.buffer)
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tileoffsetlat -= tilelat;
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tileoffsety += this.tileSize.h;
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} while(tileoffsetlat >= bounds.bottom - tilelat * this.buffer)
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//now actually draw the tiles
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this.spiralTileLoad();
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},
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/**
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* @private
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*
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* Starts at the top right corner of the grid and proceeds in a spiral
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* towards the center, adding tiles one at a time to the beginning of a
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* queue.
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*
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* Once all the grid's tiles have been added to the queue, we go back
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* and iterate through the queue (thus reversing the spiral order from
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* outside-in to inside-out), calling draw() on each tile.
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*/
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spiralTileLoad: function() {
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var tileQueue = new Array();
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var directions = ["right", "down", "left", "up"];
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var iRow = 0;
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var iCell = -1;
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var direction = directions.indexOf("right");
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var directionsTried = 0;
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while( directionsTried < directions.length) {
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var testRow = iRow;
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var testCell = iCell;
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switch (directions[direction]) {
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case "right":
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testCell++;
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break;
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case "down":
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testRow++;
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break;
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case "left":
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testCell--;
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break;
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case "up":
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testRow--;
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break;
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}
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// if the test grid coordinates are within the bounds of the
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// grid, get a reference to the tile.
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var tile = null;
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if ((testRow < this.grid.length) &&
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(testCell < this.grid[0].length)) {
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tile = this.grid[testRow][testCell];
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}
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if ((tile != null) && (!tile.queued)) {
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//add tile to beginning of queue, mark it as queued.
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tileQueue.unshift(tile);
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tile.queued = true;
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//restart the directions counter and take on the new coords
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directionsTried = 0;
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iRow = testRow;
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iCell = testCell;
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} else {
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//need to try to load a tile in a different direction
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direction = (direction + 1) % 4;
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directionsTried++;
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}
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}
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// now we go through and draw the tiles in forward order
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for(var i=0; i < tileQueue.length; i++) {
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var tile = tileQueue[i]
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tile.draw();
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//mark tile as unqueued for the next time (since tiles are reused)
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tile.queued = false;
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}
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},
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/**
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* addTile gives subclasses of Grid the opportunity to create an
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* OpenLayer.Tile of their choosing. The implementer should initialize
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* the new tile and take whatever steps necessary to display it.
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*
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* @param {OpenLayers.Bounds} bounds
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*
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* @returns The added OpenLayers.Tile
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* @type OpenLayers.Tile
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*/
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addTile:function(bounds, position) {
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// Should be implemented by subclasses
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},
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/** go through and remove all tiles from the grid, calling
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* destroy() on each of them to kill circular references
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*
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* @private
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*/
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clearGrid:function() {
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if (this.grid) {
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for(var iRow=0; iRow < this.grid.length; iRow++) {
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var row = this.grid[iRow];
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for(var iCol=0; iCol < row.length; iCol++) {
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row[iCol].clear();
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}
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}
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}
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},
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/**
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* @private
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*
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* @param {Boolean} prepend if true, prepend to beginning.
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* if false, then append to end
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*/
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shiftRow:function(prepend) {
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var modelRowIndex = (prepend) ? 0 : (this.grid.length - 1);
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var modelRow = this.grid[modelRowIndex];
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var resolution = this.map.getResolution();
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var deltaY = (prepend) ? -this.tileSize.h : this.tileSize.h;
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var deltaLat = resolution * -deltaY;
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var row = (prepend) ? this.grid.pop() : this.grid.shift();
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for (var i=0; i < modelRow.length; i++) {
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var modelTile = modelRow[i];
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var bounds = modelTile.bounds.clone();
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var position = modelTile.position.clone();
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bounds.bottom = bounds.bottom + deltaLat;
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bounds.top = bounds.top + deltaLat;
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position.y = position.y + deltaY;
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row[i].moveTo(bounds, position);
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}
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if (prepend) {
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this.grid.unshift(row);
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} else {
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this.grid.push(row);
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}
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},
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/**
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* @private
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*
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* @param {Boolean} prepend if true, prepend to beginning.
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* if false, then append to end
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*/
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shiftColumn: function(prepend) {
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var deltaX = (prepend) ? -this.tileSize.w : this.tileSize.w;
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var resolution = this.map.getResolution();
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var deltaLon = resolution * deltaX;
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for (var i=0; i<this.grid.length; i++) {
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var row = this.grid[i];
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var modelTileIndex = (prepend) ? 0 : (row.length - 1);
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var modelTile = row[modelTileIndex];
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var bounds = modelTile.bounds.clone();
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var position = modelTile.position.clone();
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bounds.left = bounds.left + deltaLon;
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bounds.right = bounds.right + deltaLon;
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position.x = position.x + deltaX;
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var tile = prepend ? this.grid[i].pop() : this.grid[i].shift()
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tile.moveTo(bounds, position);
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if (prepend) {
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this.grid[i].unshift(tile);
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} else {
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this.grid[i].push(tile);
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}
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}
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},
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/** @final @type String */
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CLASS_NAME: "OpenLayers.Layer.Grid"
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});
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