[76] | 1 | /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for |
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| 2 | * full list of contributors). Published under the Clear BSD license. |
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| 3 | * See http://svn.openlayers.org/trunk/openlayers/license.txt for the |
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| 4 | * full text of the license. */ |
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| 5 | |
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| 6 | /** |
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| 7 | * @requires OpenLayers/Layer.js |
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| 8 | * @requires OpenLayers/Tile/Image.js |
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| 9 | */ |
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| 10 | |
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| 11 | /** |
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| 12 | * Class: OpenLayers.Layer.Image |
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| 13 | * Instances of OpenLayers.Layer.Image are used to display data from a web |
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| 14 | * accessible image as a map layer. Create a new image layer with the |
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| 15 | * <OpenLayers.Layer.Image> constructor. Inherits from <OpenLayers.Layer>. |
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| 16 | */ |
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| 17 | OpenLayers.Layer.Image = OpenLayers.Class(OpenLayers.Layer, { |
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| 18 | |
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| 19 | /** |
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| 20 | * Property: isBaseLayer |
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| 21 | * {Boolean} The layer is a base layer. Default is true. Set this property |
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| 22 | * in the layer options |
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| 23 | */ |
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| 24 | isBaseLayer: true, |
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| 25 | |
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| 26 | /** |
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| 27 | * Property: url |
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| 28 | * {String} URL of the image to use |
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| 29 | */ |
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| 30 | url: null, |
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| 31 | |
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| 32 | /** |
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| 33 | * Property: extent |
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| 34 | * {<OpenLayers.Bounds>} The image bounds in map units. This extent will |
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| 35 | * also be used as the default maxExtent for the layer. If you wish |
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| 36 | * to have a maxExtent that is different than the image extent, set the |
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| 37 | * maxExtent property of the options argument (as with any other layer). |
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| 38 | */ |
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| 39 | extent: null, |
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| 40 | |
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| 41 | /** |
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| 42 | * Property: size |
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| 43 | * {<OpenLayers.Size>} The image size in pixels |
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| 44 | */ |
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| 45 | size: null, |
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| 46 | |
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| 47 | /** |
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| 48 | * Property: tile |
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| 49 | * {<OpenLayers.Tile.Image>} |
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| 50 | */ |
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| 51 | tile: null, |
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| 52 | |
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| 53 | /** |
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| 54 | * Property: aspectRatio |
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| 55 | * {Float} The ratio of height/width represented by a single pixel in the |
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| 56 | * graphic |
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| 57 | */ |
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| 58 | aspectRatio: null, |
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| 59 | |
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| 60 | /** |
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| 61 | * Constructor: OpenLayers.Layer.Image |
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| 62 | * Create a new image layer |
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| 63 | * |
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| 64 | * Parameters: |
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| 65 | * name - {String} A name for the layer. |
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| 66 | * url - {String} Relative or absolute path to the image |
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| 67 | * extent - {<OpenLayers.Bounds>} The extent represented by the image |
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| 68 | * size - {<OpenLayers.Size>} The size (in pixels) of the image |
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| 69 | * options - {Object} Hashtable of extra options to tag onto the layer |
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| 70 | */ |
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| 71 | initialize: function(name, url, extent, size, options) { |
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| 72 | this.url = url; |
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| 73 | this.extent = extent; |
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| 74 | this.maxExtent = extent; |
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| 75 | this.size = size; |
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| 76 | OpenLayers.Layer.prototype.initialize.apply(this, [name, options]); |
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| 77 | |
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| 78 | this.aspectRatio = (this.extent.getHeight() / this.size.h) / |
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| 79 | (this.extent.getWidth() / this.size.w); |
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| 80 | }, |
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| 81 | |
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| 82 | /** |
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| 83 | * Method: destroy |
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| 84 | * Destroy this layer |
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| 85 | */ |
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| 86 | destroy: function() { |
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| 87 | if (this.tile) { |
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| 88 | this.removeTileMonitoringHooks(this.tile); |
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| 89 | this.tile.destroy(); |
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| 90 | this.tile = null; |
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| 91 | } |
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| 92 | OpenLayers.Layer.prototype.destroy.apply(this, arguments); |
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| 93 | }, |
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| 94 | |
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| 95 | /** |
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| 96 | * Method: clone |
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| 97 | * Create a clone of this layer |
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| 98 | * |
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| 99 | * Paramters: |
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| 100 | * obj - {Object} An optional layer (is this ever used?) |
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| 101 | * |
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| 102 | * Returns: |
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| 103 | * {<OpenLayers.Layer.Image>} An exact copy of this layer |
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| 104 | */ |
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| 105 | clone: function(obj) { |
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| 106 | |
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| 107 | if(obj == null) { |
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| 108 | obj = new OpenLayers.Layer.Image(this.name, |
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| 109 | this.url, |
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| 110 | this.extent, |
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| 111 | this.size, |
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| 112 | this.getOptions()); |
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| 113 | } |
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| 114 | |
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| 115 | //get all additions from superclasses |
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| 116 | obj = OpenLayers.Layer.prototype.clone.apply(this, [obj]); |
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| 117 | |
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| 118 | // copy/set any non-init, non-simple values here |
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| 119 | |
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| 120 | return obj; |
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| 121 | }, |
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| 122 | |
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| 123 | /** |
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| 124 | * APIMethod: setMap |
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| 125 | * |
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| 126 | * Parameters: |
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| 127 | * map - {<OpenLayers.Map>} |
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| 128 | */ |
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| 129 | setMap: function(map) { |
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| 130 | /** |
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| 131 | * If nothing to do with resolutions has been set, assume a single |
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| 132 | * resolution determined by ratio*extent/size - if an image has a |
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| 133 | * pixel aspect ratio different than one (as calculated above), the |
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| 134 | * image will be stretched in one dimension only. |
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| 135 | */ |
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| 136 | if( this.options.maxResolution == null ) { |
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| 137 | this.options.maxResolution = this.aspectRatio * |
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| 138 | this.extent.getWidth() / |
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| 139 | this.size.w; |
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| 140 | } |
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| 141 | OpenLayers.Layer.prototype.setMap.apply(this, arguments); |
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| 142 | }, |
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| 143 | |
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| 144 | /** |
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| 145 | * Method: moveTo |
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| 146 | * Create the tile for the image or resize it for the new resolution |
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| 147 | * |
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| 148 | * Parameters: |
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| 149 | * bounds - {<OpenLayers.Bounds>} |
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| 150 | * zoomChanged - {Boolean} |
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| 151 | * dragging - {Boolean} |
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| 152 | */ |
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| 153 | moveTo:function(bounds, zoomChanged, dragging) { |
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| 154 | OpenLayers.Layer.prototype.moveTo.apply(this, arguments); |
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| 155 | |
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| 156 | var firstRendering = (this.tile == null); |
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| 157 | |
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| 158 | if(zoomChanged || firstRendering) { |
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| 159 | |
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| 160 | //determine new tile size |
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| 161 | this.setTileSize(); |
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| 162 | |
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| 163 | //determine new position (upper left corner of new bounds) |
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| 164 | var ul = new OpenLayers.LonLat(this.extent.left, this.extent.top); |
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| 165 | var ulPx = this.map.getLayerPxFromLonLat(ul); |
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| 166 | |
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| 167 | if(firstRendering) { |
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| 168 | //create the new tile |
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| 169 | this.tile = new OpenLayers.Tile.Image(this, ulPx, this.extent, |
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| 170 | null, this.tileSize); |
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| 171 | this.addTileMonitoringHooks(this.tile); |
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| 172 | } else { |
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| 173 | //just resize the tile and set it's new position |
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| 174 | this.tile.size = this.tileSize.clone(); |
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| 175 | this.tile.position = ulPx.clone(); |
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| 176 | } |
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| 177 | this.tile.draw(); |
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| 178 | } |
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| 179 | }, |
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| 180 | |
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| 181 | /** |
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| 182 | * Set the tile size based on the map size. |
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| 183 | */ |
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| 184 | setTileSize: function() { |
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| 185 | var tileWidth = this.extent.getWidth() / this.map.getResolution(); |
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| 186 | var tileHeight = this.extent.getHeight() / this.map.getResolution(); |
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| 187 | this.tileSize = new OpenLayers.Size(tileWidth, tileHeight); |
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| 188 | }, |
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| 189 | |
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| 190 | /** |
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| 191 | * Method: addTileMonitoringHooks |
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| 192 | * This function takes a tile as input and adds the appropriate hooks to |
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| 193 | * the tile so that the layer can keep track of the loading tiles. |
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| 194 | * |
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| 195 | * Parameters: |
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| 196 | * tile - {<OpenLayers.Tile>} |
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| 197 | */ |
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| 198 | addTileMonitoringHooks: function(tile) { |
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| 199 | tile.onLoadStart = function() { |
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| 200 | this.events.triggerEvent("loadstart"); |
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| 201 | }; |
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| 202 | tile.events.register("loadstart", this, tile.onLoadStart); |
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| 203 | |
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| 204 | tile.onLoadEnd = function() { |
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| 205 | this.events.triggerEvent("loadend"); |
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| 206 | }; |
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| 207 | tile.events.register("loadend", this, tile.onLoadEnd); |
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| 208 | tile.events.register("unload", this, tile.onLoadEnd); |
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| 209 | }, |
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| 210 | |
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| 211 | /** |
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| 212 | * Method: removeTileMonitoringHooks |
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| 213 | * This function takes a tile as input and removes the tile hooks |
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| 214 | * that were added in <addTileMonitoringHooks>. |
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| 215 | * |
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| 216 | * Parameters: |
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| 217 | * tile - {<OpenLayers.Tile>} |
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| 218 | */ |
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| 219 | removeTileMonitoringHooks: function(tile) { |
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| 220 | tile.unload(); |
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| 221 | tile.events.un({ |
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| 222 | "loadstart": tile.onLoadStart, |
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| 223 | "loadend": tile.onLoadEnd, |
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| 224 | "unload": tile.onLoadEnd, |
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| 225 | scope: this |
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| 226 | }); |
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| 227 | }, |
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| 228 | |
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| 229 | /** |
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| 230 | * APIMethod: setUrl |
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| 231 | * |
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| 232 | * Parameters: |
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| 233 | * newUrl - {String} |
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| 234 | */ |
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| 235 | setUrl: function(newUrl) { |
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| 236 | this.url = newUrl; |
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| 237 | this.tile.draw(); |
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| 238 | }, |
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| 239 | |
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| 240 | /** |
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| 241 | * APIMethod: getURL |
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| 242 | * The url we return is always the same (the image itself never changes) |
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| 243 | * so we can ignore the bounds parameter (it will always be the same, |
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| 244 | * anyways) |
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| 245 | * |
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| 246 | * Parameters: |
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| 247 | * bounds - {<OpenLayers.Bounds>} |
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| 248 | */ |
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| 249 | getURL: function(bounds) { |
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| 250 | return this.url; |
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| 251 | }, |
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| 252 | |
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| 253 | CLASS_NAME: "OpenLayers.Layer.Image" |
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| 254 | }); |
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