Merge pull request #114 from ahocevar/resolutions

Use validity extent to generate default resolutions. r=@twpayne,@elemoine

examples/wms-custom-proj.js

@@ -52,7 +52,6 @@ var layers = new ol.Collection([
 ]);
 
 var map = new ol.Map({
-  projection: epsg21781,
   // By setting userProjection to the same as projection, we do not need
   // proj4js because we do not need any transforms.
   userProjection: epsg21781,
@@ -60,7 +59,8 @@ var map = new ol.Map({
   renderers: ol.RendererHints.createFromQueryData(),
   target: 'map',
   view: new ol.View2D({
+    projection: epsg21781,
     center: new ol.Coordinate(660000, 190000),
-    zoom: 9
+    zoom: 2
   })
 });

src/ol/source/tiledwmssource.js

@@ -35,20 +35,8 @@ ol.source.TiledWMS = function(tiledWMSOptions) {
   if (goog.isDef(tiledWMSOptions.tileGrid)) {
     tileGrid = tiledWMSOptions.tileGrid;
   } else {
-    // FIXME Factor this out to a more central/generic place.
+    tileGrid = ol.tilegrid.createForProjection(projection,
-    var size = Math.max(
+        tiledWMSOptions.maxZoom);
-        projectionExtent.maxX - projectionExtent.minX,
-        projectionExtent.maxY - projectionExtent.minY);
-    var maxZoom = goog.isDef(tiledWMSOptions.maxZoom) ?
-        tiledWMSOptions.maxZoom : 18;
-    var resolutions = new Array(maxZoom + 1);
-    for (var z = 0, zz = resolutions.length; z < zz; ++z) {
-      resolutions[z] = ol.Projection.EPSG_3857_HALF_SIZE / (128 << z);
-    }
-    tileGrid = new ol.tilegrid.TileGrid({
-      origin: projectionExtent.getTopLeft(),
-      resolutions: resolutions
-    });
   }
 
   var baseParams = {

src/ol/tilegrid/tilegrid.js

@@ -316,3 +316,26 @@ ol.tilegrid.TileGrid.prototype.getTileSize = function() {
 ol.tilegrid.TileGrid.prototype.getZForResolution = function(resolution) {
   return ol.array.linearFindNearest(this.resolutions_, resolution);
 };
+
+
+/**
+ * @param {ol.Projection} projection Projection.
+ * @param {number=} opt_maxZoom Maximum zoom level (optional). Default is 18.
+ * @return {ol.tilegrid.TileGrid} TileGrid instance.
+ */
+ol.tilegrid.createForProjection = function(projection, opt_maxZoom) {
+  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 resolutions = new Array(maxZoom + 1);
+  for (var z = 0, zz = resolutions.length; z < zz; ++z) {
+    resolutions[z] = size / (256 << z);
+  }
+  return new ol.tilegrid.TileGrid({
+    origin: projectionExtent.getTopLeft(),
+    resolutions: resolutions
+  });
+};

src/ol/view2d.js

@@ -48,8 +48,11 @@ ol.View2D = function(opt_view2DOptions) {
   if (goog.isDef(view2DOptions.resolution)) {
     values[ol.View2DProperty.RESOLUTION] = view2DOptions.resolution;
   } else if (goog.isDef(view2DOptions.zoom)) {
-    values[ol.View2DProperty.RESOLUTION] =
+    var projectionExtent = values[ol.View2DProperty.PROJECTION].getExtent();
-        ol.Projection.EPSG_3857_HALF_SIZE / (128 << view2DOptions.zoom);
+    var size = Math.max(
+        projectionExtent.maxX - projectionExtent.minX,
+        projectionExtent.maxY - projectionExtent.minY);
+    values[ol.View2DProperty.RESOLUTION] = size / (256 << view2DOptions.zoom);
   }
   values[ol.View2DProperty.ROTATION] = view2DOptions.rotation;
   this.setValues(values);
@@ -322,7 +325,11 @@ ol.View2D.createConstraints_ = function(view2DOptions) {
       numZoomLevels = view2DOptions.numZoomLevels;
       zoomFactor = view2DOptions.zoomFactor;
     } else {
-      maxResolution = ol.Projection.EPSG_3857_HALF_SIZE / 128;
+      var projectionExtent = ol.Projection.createProjection(
+          view2DOptions.projection, 'EPSG:3857').getExtent();
+      maxResolution = Math.max(
+          projectionExtent.maxX - projectionExtent.minX,
+          projectionExtent.maxY - projectionExtent.minY) / 256;
       // number of steps we want between two data resolutions
       var numSteps = 4;
       numZoomLevels = 29 * numSteps;