Preliminary working implementation.. still lots of slop to clean up

lib/OpenLayers/Layer/UTFGrid.js

@@ -172,11 +172,24 @@ OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.Grid, {
 
     getTile: function(loc) {
         var info = this.getTileInfo(loc);
+        var res = this.getServerResolution();
+
+        var gridOrigin = this.grid[0][0].bounds;
+        var gridColOffset = (gridOrigin.left - this.tileOrigin.lon)  / (res * this.tileSize.w);
+        var gridRowOffset = (this.tileOrigin.lat - gridOrigin.top) / (res * this.tileSize.h);
+
+        var fx = (loc.lon - this.tileOrigin.lon) / (res * this.tileSize.w);
+        var fy = (this.tileOrigin.lat - loc.lat) / (res * this.tileSize.h);
+        var globalCol = Math.floor(fx);
+        var globalRow = Math.floor(fy);
+
+        var row = globalRow - Math.floor(gridRowOffset);
+        var col = globalCol - Math.floor(gridColOffset);
+
         var tile = null;
-        //TODO how to find the tile instance given a lonLat
+        var therow = this.grid[row];
-        var row = this.grid[1]; //info.row];
+        if (typeof(therow) !== 'undefined' && therow !== null) {
-        if (typeof(row) !== 'undefined' && row !== null) {
+            tile = therow[col];
-            tile = row[1]; //info.col];
         }
         return tile;
     },

lib/OpenLayers/Tile/UTFGrid.js

@@ -27,9 +27,9 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
     url: null,
     
     /** 
-     * Property: imgDiv
+     * Property: json
      * TODO
-     * {HTMLImageElement} The image for this tile.
+     * {Object} The image for this tile.
      */
     json: null,
 
@@ -111,7 +111,6 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
              * TODO Investigate JSONP method to avoid xbrowser polucy
              *
             grid = function(e) { 
-                console.log("-----------");
                 console.log(e);
             };