if maxResolution is "auto" calculate maxResolution based on maxExtent and map size, else calculate maxResolution based on maxExtent and tile size

lib/OpenLayers/Layer.js

@@ -884,16 +884,6 @@ OpenLayers.Layer = OpenLayers.Class({
                 props.resolutions = this.resolutionsFromScales(props.scales);
             }
             if(props.resolutions == null) {
-                var maxExtent = this.maxExtent;
-                if (!props.maxResolution && maxExtent) {
-                    // maxResolution for default grid sets assumes that at zoom
-                    // level zero, the whole world fits on one tile.
-                    var tileSize = this.tileSize || this.map.getTileSize();
-                    props.maxResolution = Math.max(
-                        maxExtent.getWidth() / tileSize.w,
-                        maxExtent.getHeight() / tileSize.h
-                    );
-                }
                 props.resolutions = this.calculateResolutions(props);
             }
         }
@@ -1029,6 +1019,18 @@ OpenLayers.Layer = OpenLayers.Class({
             minResolution = Math.max(wRes, hRes);
         }
 
+        if(typeof maxResolution !== "number" &&
+           typeof minResolution !== "number" &&
+           this.maxExtent != null) {
+            // maxResolution for default grid sets assumes that at zoom
+            // level zero, the whole world fits on one tile.
+            var tileSize = this.tileSize || this.map.getTileSize();
+            maxResolution = Math.max(
+                this.maxExtent.getWidth() / tileSize.w,
+                this.maxExtent.getHeight() / tileSize.h
+            );
+        }
+
         // determine numZoomLevels
         var maxZoomLevel = props.maxZoomLevel;
         var numZoomLevels = props.numZoomLevels;

tests/Layer.html

@@ -398,6 +398,9 @@
             "1.20",  null, {maxScale: 100000, numZoomLevels: 3, units: "m"},
             [141.11103491115225, 70.55551745557612, 35.27775872778806], 35.27775872778806, 141.11103491115225
         ], [
+            "1.21", null, {numZoomLevels: 2},  // maxResolution calculated based on the projection's maxExtent here
+           [1.40625, 0.703125], 0.703125, 1.40625
+        ], [
 
         /*
          * Batch 2: custom map options map and sensible layer options
@@ -541,8 +544,8 @@
         /*
          * Batch 2.8: numZoomLevels set in the layer options
          */
-            "2.8.0",  {maxResolution: 80}, {numZoomLevels: 4},
+            "2.8.0",  {maxResolution: 80}, {numZoomLevels: 4},  // maxResolution calculated based on the projection's maxExtent here
-            [80, 40, 20, 10], 10, 80
+            [1.40625, 0.703125, 0.3515625, 0.17578125], 0.17578125, 1.40625
         ], [
             "2.8.1", {maxResolution: 80, numZoomLevels: 4}, {numZoomLevels: null},
             [80, 40, 20, 10], 10, 80