Layer.TileCache, Layer.TMS: support a subset of server resolutions. r=tschaub (closes #1944)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@8932 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

examples/tilecache.html

@@ -7,7 +7,9 @@
     <script type="text/javascript">
         var map, layer;
         function init(){
-            map = new OpenLayers.Map( $('map'));
+            map = new OpenLayers.Map( $('map'), {
+                resolutions: [0.087890625, 0.0439453125, 0.02197265625, 0.010986328125]
+            });
             layer = new OpenLayers.Layer.TileCache("TileCache Layer",
                 ["http://c0.labs.metacarta.com/wms-c/cache/",
                  "http://c1.labs.metacarta.com/wms-c/cache/",
@@ -16,8 +18,11 @@
                  "http://c4.labs.metacarta.com/wms-c/cache/"],
                 "basic",
                 {
-                    'format': 'image/png',
+                    serverResolutions: [0.703125, 0.3515625, 0.17578125, 0.087890625, 
-                    maxResolution: 180/256 // same as the TileCache config
+                                        0.0439453125, 0.02197265625, 0.010986328125, 
+                                        0.0054931640625, 0.00274658203125, 0.001373291015625, 
+                                        0.0006866455078125, 0.00034332275390625, 0.000171661376953125, 
+                                        0.0000858306884765625, 0.00004291534423828125, 0.000021457672119140625]
                 }
             );
             map.addLayer(layer);

lib/OpenLayers/Layer/TMS.js

@@ -34,6 +34,13 @@ OpenLayers.Layer.TMS = OpenLayers.Class(OpenLayers.Layer.Grid, {
      */
     tileOrigin: null,
 
+    /**
+     * APIProperty: serverResolutions
+     * {Array} A list of all resolutions available on the server.  Only set this 
+     *     property if the map resolutions differs from the server.
+     */
+    serverResolutions: null,
+
     /**
      * Constructor: OpenLayers.Layer.TMS
      * 
@@ -98,7 +105,7 @@ OpenLayers.Layer.TMS = OpenLayers.Class(OpenLayers.Layer.Grid, {
         var res = this.map.getResolution();
         var x = Math.round((bounds.left - this.tileOrigin.lon) / (res * this.tileSize.w));
         var y = Math.round((bounds.bottom - this.tileOrigin.lat) / (res * this.tileSize.h));
-        var z = this.map.getZoom();
+        var z = this.serverResolutions != null ? this.serverResolutions.indexOf(res) : this.map.getZoom();
         var path = this.serviceVersion + "/" + this.layername + "/" + z + "/" + x + "/" + y + "." + this.type; 
         var url = this.url;
         if (url instanceof Array) {

lib/OpenLayers/Layer/TileCache.js

@@ -33,6 +33,13 @@ OpenLayers.Layer.TileCache = OpenLayers.Class(OpenLayers.Layer.Grid, {
      */
     format: 'image/png',
 
+    /**
+     * APIProperty: serverResolutions
+     * {Array} A list of all resolutions available on the server.  Only set this 
+     *     property if the map resolutions differs from the server.
+     */
+    serverResolutions: null,
+
     /**
      * Constructor: OpenLayers.Layer.TileCache
      * Create a new read only TileCache layer.
@@ -98,7 +105,7 @@ OpenLayers.Layer.TileCache = OpenLayers.Class(OpenLayers.Layer.Grid, {
         var size = this.tileSize;
         var tileX = Math.round((bounds.left - bbox.left) / (res * size.w));
         var tileY = Math.round((bounds.bottom - bbox.bottom) / (res * size.h));
-        var tileZ = this.map.zoom;
+        var tileZ = this.serverResolutions != null ? this.serverResolutions.indexOf(res) : this.map.getZoom();
         /**
          * Zero-pad a positive integer.
          * number - {Int} 

tests/Layer/TMS.html

@@ -141,6 +141,28 @@
         m.destroy();
     }        
             
+    function test_Layer_TMS_serverResolutions(t) {
+        t.plan(2);
+        
+        var map = new OpenLayers.Map('map', {
+            resolutions: [13,11]
+        });
+
+        var layer = new OpenLayers.Layer.TMS('tc layer', '', options);
+        map.addLayer(layer);
+        map.setCenter(new OpenLayers.LonLat(0,0), 1);
+
+        var tileurl = layer.getURL(new OpenLayers.Bounds(0,0,0,0));
+        var level = parseInt(tileurl.split('/')[2]);
+        t.eq(map.getZoom(), level, "Tile zoom level is correct without serverResolutions");
+
+        layer.serverResolutions = [14,13,12,11,10];
+        tileurl = layer.getURL(new OpenLayers.Bounds(0,0,0,0));
+        level = parseInt(tileurl.split('/')[2]);
+        t.eq(layer.serverResolutions.indexOf(map.getResolution()), level, "Tile zoom level is correct with serverResolutions");
+        
+        map.destroy();
+    }
 
     function test_Layer_TMS_setMap(t) {
 

tests/Layer/TileCache.html

@@ -18,7 +18,7 @@
         layer.destroy();
     }
 
-    function test__Layer_TileCache_clone(t) {
+    function test_Layer_TileCache_clone(t) {
         t.plan(3);
 
         var name = 'Test Layer';
@@ -141,6 +141,29 @@
         map.destroy();
     }
 
+    function test_Layer_TileCache_serverResolutions(t) {
+        t.plan(2);
+        
+        var map = new OpenLayers.Map('map', {
+            resolutions: [13,11]
+        });
+
+        var layer = new OpenLayers.Layer.TileCache('tc layer', '', 'basic');
+        map.addLayer(layer);
+        map.setCenter(new OpenLayers.LonLat(0,0), 1);
+
+        var tileurl = layer.getURL(new OpenLayers.Bounds(0,0,0,0));
+        var level = parseInt(tileurl.split('/')[2]);
+        t.eq(map.getZoom(), level, "Tile zoom level is correct without serverResolutions");
+
+        layer.serverResolutions = [14,13,12,11,10];
+        tileurl = layer.getURL(new OpenLayers.Bounds(0,0,0,0));
+        level = parseInt(tileurl.split('/')[2]);
+        t.eq(layer.serverResolutions.indexOf(map.getResolution()), level, "Tile zoom level is correct with serverResolutions");
+        
+        map.destroy();
+    }
+
     function test_Layer_TileCache_setMap(t) {
 
         t.plan(3);