Add default tile size @define, refs #114, fixes #120

src/ol/tilegrid/tilegrid.js

@@ -14,6 +14,12 @@ goog.require('ol.TileRange');
 goog.require('ol.array');
 
 
+/**
+ * @define {number} Default tile size.
+ */
+ol.DEFAULT_TILE_SIZE = 256;
+
+
 /**
  * @typedef {{extent: (ol.Extent|undefined),
  *            origin: (ol.Coordinate|undefined),
@@ -75,7 +81,8 @@ ol.tilegrid.TileGrid = function(tileGridOptions) {
    * @type {ol.Size}
    */
   this.tileSize_ = goog.isDef(tileGridOptions.tileSize) ?
-      tileGridOptions.tileSize : new ol.Size(256, 256);
+      tileGridOptions.tileSize :
+      new ol.Size(ol.DEFAULT_TILE_SIZE, ol.DEFAULT_TILE_SIZE);
 
 };
 
@@ -321,21 +328,27 @@ ol.tilegrid.TileGrid.prototype.getZForResolution = function(resolution) {
 /**
  * @param {ol.Projection} projection Projection.
  * @param {number=} opt_maxZoom Maximum zoom level (optional). Default is 18.
+ * @param {ol.Size=} opt_tileSize Tile size.
  * @return {ol.tilegrid.TileGrid} TileGrid instance.
  */
-ol.tilegrid.createForProjection = function(projection, opt_maxZoom) {
+ol.tilegrid.createForProjection =
+    function(projection, opt_maxZoom, opt_tileSize) {
   var projectionExtent = projection.getExtent();
   var size = Math.max(
       projectionExtent.maxX - projectionExtent.minX,
       projectionExtent.maxY - projectionExtent.minY);
   var maxZoom = goog.isDef(opt_maxZoom) ?
       opt_maxZoom : 18;
+  var tileSize = goog.isDef(opt_tileSize) ?
+      opt_tileSize : new ol.Size(ol.DEFAULT_TILE_SIZE, ol.DEFAULT_TILE_SIZE);
   var resolutions = new Array(maxZoom + 1);
+  goog.asserts.assert(tileSize.width == tileSize.height);
   for (var z = 0, zz = resolutions.length; z < zz; ++z) {
-    resolutions[z] = size / (256 << z);
+    resolutions[z] = size / (tileSize.width << z);
   }
   return new ol.tilegrid.TileGrid({
     origin: projectionExtent.getTopLeft(),
-    resolutions: resolutions
+    resolutions: resolutions,
+    tileSize: tileSize
   });
 };

src/ol/tilegrid/xyztilegrid.js

@@ -25,7 +25,8 @@ ol.tilegrid.XYZ = function(xyzOptions) {
   var resolutions = new Array(xyzOptions.maxZoom + 1);
   var z;
   for (z = 0; z <= xyzOptions.maxZoom; ++z) {
-    resolutions[z] = ol.Projection.EPSG_3857_HALF_SIZE / (128 << z);
+    resolutions[z] =
+        2 * ol.Projection.EPSG_3857_HALF_SIZE / (ol.DEFAULT_TILE_SIZE << z);
   }
 
   goog.base(this, {
@@ -33,7 +34,7 @@ ol.tilegrid.XYZ = function(xyzOptions) {
     origin: new ol.Coordinate(-ol.Projection.EPSG_3857_HALF_SIZE,
                               ol.Projection.EPSG_3857_HALF_SIZE),
     resolutions: resolutions,
-    tileSize: new ol.Size(256, 256)
+    tileSize: new ol.Size(ol.DEFAULT_TILE_SIZE, ol.DEFAULT_TILE_SIZE)
   });
 
 };

src/ol/view2d.js

@@ -52,7 +52,8 @@ ol.View2D = function(opt_view2DOptions) {
     var size = Math.max(
         projectionExtent.maxX - projectionExtent.minX,
         projectionExtent.maxY - projectionExtent.minY);
-    values[ol.View2DProperty.RESOLUTION] = size / (256 << view2DOptions.zoom);
+    values[ol.View2DProperty.RESOLUTION] =
+        size / (ol.DEFAULT_TILE_SIZE << view2DOptions.zoom);
   }
   values[ol.View2DProperty.ROTATION] = view2DOptions.rotation;
   this.setValues(values);
@@ -329,7 +330,7 @@ ol.View2D.createConstraints_ = function(view2DOptions) {
           view2DOptions.projection, 'EPSG:3857').getExtent();
       maxResolution = Math.max(
           projectionExtent.maxX - projectionExtent.minX,
-          projectionExtent.maxY - projectionExtent.minY) / 256;
+          projectionExtent.maxY - projectionExtent.minY) / ol.DEFAULT_TILE_SIZE;
       // number of steps we want between two data resolutions
       var numSteps = 4;
       numZoomLevels = 29 * numSteps;