Fixing KaMap layer

This also fixes an issue that has gone unnoticed for a while: the grid did
not cover the bottom of the map viewport, but instead covered an invisible
area above the top of the map viewport.

lib/OpenLayers/Layer/KaMap.js

@@ -92,8 +92,8 @@ OpenLayers.Layer.KaMap = OpenLayers.Class(OpenLayers.Layer.Grid, {
      * resolution - {Number}
      *
      * Returns:
-     * {Object} Object containing properties tilelon, tilelat, tileoffsetlat,
+     * {Object} Object containing properties tilelon, tilelat, tileoffsetx,
-     * tileoffsetlat, tileoffsetx, tileoffsety
+     * tileoffsety, startcol, startrow
      */
     calculateGridLayout: function(bounds, origin, resolution) {
         var tilelon = resolution*this.tileSize.w;
@@ -103,22 +103,42 @@ OpenLayers.Layer.KaMap = OpenLayers.Class(OpenLayers.Layer.Grid, {
         var tilecol = Math.floor(offsetlon/tilelon) - this.buffer;
         var tilecolremain = offsetlon/tilelon - tilecol;
         var tileoffsetx = -tilecolremain * this.tileSize.w;
-        var tileoffsetlon = tilecol * tilelon;
         
         var offsetlat = bounds.top;  
-        var tilerow = Math.ceil(offsetlat/tilelat) + this.buffer;
+        var tilerow = Math.floor(offsetlat/tilelat) + this.buffer;
         var tilerowremain = tilerow - offsetlat/tilelat;
         var tileoffsety = -(tilerowremain+1) * this.tileSize.h;
-        var tileoffsetlat = tilerow * tilelat;
         
         return { 
           tilelon: tilelon, tilelat: tilelat,
-          tileoffsetlon: tileoffsetlon, tileoffsetlat: tileoffsetlat,
           tileoffsetx: tileoffsetx, tileoffsety: tileoffsety,
           startcol: tilecol, startrow: tilerow
         };
     },    
 
+    /**
+     * Method: getTileBoundsForGridIndex
+     *
+     * Parameters:
+     * row - {Number} The row of the grid
+     * col - {Number} The column of the grid
+     *
+     * Returns:
+     * {<OpenLayers.Bounds>} The bounds for the tile at (row, col)
+     */
+    getTileBoundsForGridIndex: function(row, col) {
+        var origin = this.getTileOrigin();
+        var tileLayout = this.gridLayout;
+        var tilelon = tileLayout.tilelon;
+        var tilelat = tileLayout.tilelat;
+        var minX = (tileLayout.startcol + col) * tilelon;
+        var minY = (tileLayout.startrow - row) * tilelat;
+        return new OpenLayers.Bounds(
+            minX, minY,
+            minX + tilelon, minY + tilelat
+        );
+    },
+
     /**
      * APIMethod: clone
      * 

tests/Layer/WrapDateLine.html

@@ -154,9 +154,9 @@
         var m = new OpenLayers.Map('map', {adjustZoom: function(z) {return z;}});
         m.addLayer(layer);
         m.zoomToMaxExtent();
-        t.eq(layer.grid[5][7].url, "http://www.openlayers.org/world/index.php?g=satellite&map=world&i=jpeg&t=0&l=-256&s=221471921.25", "grid[5][7] kamap is okay");
+        t.eq(layer.grid[4][7].url, "http://www.openlayers.org/world/index.php?g=satellite&map=world&i=jpeg&t=0&l=-256&s=221471921.25", "grid[5][7] kamap is okay");
-        t.eq(layer.grid[5][6].url, "http://www.openlayers.org/world/index.php?g=satellite&map=world&i=jpeg&t=0&l=0&s=221471921.25", "grid[5][6] kamap is okay");
+        t.eq(layer.grid[4][6].url, "http://www.openlayers.org/world/index.php?g=satellite&map=world&i=jpeg&t=0&l=0&s=221471921.25", "grid[5][6] kamap is okay");
-        t.eq(layer.grid[5][5].url, "http://www.openlayers.org/world/index.php?g=satellite&map=world&i=jpeg&t=0&l=-256&s=221471921.25", "grid[5][5] is okay");
+        t.eq(layer.grid[4][5].url, "http://www.openlayers.org/world/index.php?g=satellite&map=world&i=jpeg&t=0&l=-256&s=221471921.25", "grid[5][5] is okay");
         t.ok(layer.grid[7][6].url == null, "no latitudinal wrapping - tile not loaded if outside maxExtent");
         m.destroy();
     }