Merge pull request #51 from ahocevar/adjust-zoom

Don't let wrapDateLine maps be wider than one world width. r=@bartvde (closes http://trac.openlayers.org/ticket/3574)

lib/OpenLayers/Map.js

@@ -1701,6 +1701,30 @@ OpenLayers.Map = OpenLayers.Class({
             this.events.triggerEvent("move");
         }
     },
+    
+    /**
+     * Method: adjustZoom
+     *
+     * Parameters:
+     * zoom - {Number} The zoom level to adjust
+     *
+     * Returns:
+     * {Integer} Adjusted zoom level that shows a map not wider than its
+     * <baseLayer>'s maxExtent.
+     */
+    adjustZoom: function(zoom) {
+        var resolution, resolutions = this.baseLayer.resolutions,
+            maxResolution = this.getMaxExtent().getWidth() / this.getSize().w;
+        if (this.getResolutionForZoom(zoom) > maxResolution) {
+            for (var i=zoom|0, ii=resolutions.length; i<ii; ++i) {
+                if (resolutions[i] <= maxResolution) {
+                    zoom = i;
+                    break;
+                }
+            }
+        }
+        return zoom;
+    },
 
     /**
      * Method: moveTo
@@ -1723,6 +1747,9 @@ OpenLayers.Map = OpenLayers.Class({
                 zoom = Math.round(zoom);
             }
         }
+        if (this.baseLayer.wrapDateLine) {
+            zoom = this.adjustZoom(zoom);
+        }
         // dragging is false by default
         var dragging = options.dragging || this.dragging;
         // forceZoomChange is false by default

tests/Layer/WrapDateLine.html

@@ -131,7 +131,7 @@
 
         var url = "http://octo.metacarta.com/cgi-bin/mapserv";
         layer = new OpenLayers.Layer.WMS(name, url, params, {'wrapDateLine':true,encodeBBOX:true, buffer: 2});
-        var m = new OpenLayers.Map('map');
+        var m = new OpenLayers.Map('map', {adjustZoom: function(z) {return z;}});
         m.addLayer(layer);
         m.zoomToMaxExtent();
         t.eq(layer.grid[3][0].url, "http://octo.metacarta.com/cgi-bin/mapserv?MAP=%2Fmapdata%2Fvmap_wms.map&LAYERS=basic&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A4326&BBOX=0%2C-90%2C180%2C90&WIDTH=256&HEIGHT=256", "cell [3][0] is wrapped around the world.");
@@ -147,7 +147,7 @@
              "http://www.openlayers.org/world/index.php",
              {g: "satellite", map: "world"},
              {wrapDateLine: true, buffer: 2} ); 
-        var m = new OpenLayers.Map('map');
+        var m = new OpenLayers.Map('map', {adjustZoom: function(z) {return z;}});
         m.addLayer(layer);
         m.zoomToMaxExtent();
         t.eq(layer.grid[0][0].url, "http://www.openlayers.org/world/index.php?g=satellite&map=world&i=jpeg&t=-1280&l=0&s=221471921.25", "grid[0][0] kamap is okay");
@@ -165,7 +165,7 @@
                      "prov_bound,fedlimit,rail,road,popplace",
              transparent: "true", format: "image/png"},
             {wrapDateLine: true, reproject: false,encodeBBOX:true, buffer:2});
-        var m = new OpenLayers.Map('map');
+        var m = new OpenLayers.Map('map', {adjustZoom: function(z) {return z;}});
         m.addLayers([baselayer,layer]);
         m.zoomToMaxExtent();
         t.eq(layer.grid[0][0].url, "http://www2.dmsolutions.ca/cgi-bin/mswms_gmap?LAYERS=bathymetry%2Cland_fn%2Cpark%2Cdrain_fn%2Cdrainage%2Cprov_bound%2Cfedlimit%2Crail%2Croad%2Cpopplace&TRANSPARENT=true&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A4326&BBOX=0%2C450%2C180%2C630&WIDTH=256&HEIGHT=256", "grid[0][0] wms overlay is okay");

tests/Map.html

@@ -1967,6 +1967,23 @@
         t.eq(map.layerContainerDiv.style.top, '0px', 'layer container top correct');
     }
 
+    function test_adjustZoom(t) {
+        t.plan(3);
+        var map = new OpenLayers.Map({
+            div: 'map',
+            layers: [
+                new OpenLayers.Layer('name', {
+                    isBaseLayer: true,
+                    wrapDateLine: true
+                })
+            ]
+        });
+        map.zoomToMaxExtent();
+        t.ok(map.getResolution() <= map.getMaxExtent().getWidth() / map.getSize().w, "wrapDateLine map not wider than world");
+        
+        t.eq(map.adjustZoom(9), 9, "valid zoom maintained");
+        t.eq(map.adjustZoom(1), 2, "zoom adjusted to not exceed world width");
+    }
 
   </script>
 </head>