Merge pull request #7431 from tschaub/defined-zoom

Avoid returning undefined zoom
openlayers · Nov 8, 2017 · 3a6fc7a · 3a6fc7a
2 parents be06224 + 967118e
commit 3a6fc7a
Show file tree

Hide file tree

Showing 2 changed files with 21 additions and 23 deletions.
diff --git a/src/ol/view.js b/src/ol/view.js
@@ -788,8 +788,9 @@ ol.View.prototype.getState = function() {
 
 
 /**
- * Get the current zoom level. Return undefined if the current
- * resolution is undefined or not within the "resolution constraints".
+ * Get the current zoom level.  If you configured your view with a resolutions
+ * array (this is rare), this method may return non-integer zoom levels (so
+ * the zoom level is not safe to use as an index into a resolutions array).
  * @return {number|undefined} Zoom.
  * @api
  */
@@ -810,25 +811,22 @@ ol.View.prototype.getZoom = function() {
  * @api
  */
 ol.View.prototype.getZoomForResolution = function(resolution) {
-  var zoom;
-  if (resolution >= this.minResolution_ && resolution <= this.maxResolution_) {
-    var offset = this.minZoom_ || 0;
-    var max, zoomFactor;
-    if (this.resolutions_) {
-      var nearest = ol.array.linearFindNearest(this.resolutions_, resolution, 1);
-      offset += nearest;
-      if (nearest == this.resolutions_.length - 1) {
-        return offset;
-      }
-      max = this.resolutions_[nearest];
-      zoomFactor = max / this.resolutions_[nearest + 1];
+  var offset = this.minZoom_ || 0;
+  var max, zoomFactor;
+  if (this.resolutions_) {
+    var nearest = ol.array.linearFindNearest(this.resolutions_, resolution, 1);
+    offset += nearest;
+    max = this.resolutions_[nearest];
+    if (nearest == this.resolutions_.length - 1) {
+      zoomFactor = 2;
     } else {
-      max = this.maxResolution_;
-      zoomFactor = this.zoomFactor_;
+      zoomFactor = max / this.resolutions_[nearest + 1];
     }
-    zoom = offset + Math.log(max / resolution) / Math.log(zoomFactor);
+  } else {
+    max = this.maxResolution_;
+    zoomFactor = this.zoomFactor_;
   }
-  return zoom;
+  return offset + Math.log(max / resolution) / Math.log(zoomFactor);
 };
 
 

diff --git a/test/spec/ol/view.test.js b/test/spec/ol/view.test.js
@@ -1,5 +1,3 @@
-
-
 goog.require('ol');
 goog.require('ol.Map');
 goog.require('ol.View');
@@ -943,12 +941,12 @@ describe('ol.View', function() {
       });
     });
 
-    it('returns correct zoom levels', function() {
+    it('returns correct zoom levels (with resolutions array)', function() {
       view.setResolution(undefined);
       expect(view.getZoom()).to.be(undefined);
 
       view.setResolution(513);
-      expect(view.getZoom()).to.be(undefined);
+      expect(view.getZoom()).to.roughlyEqual(Math.log(512 / 513) / Math.LN2, 1e-9);
 
       view.setResolution(512);
       expect(view.getZoom()).to.be(0);
@@ -966,7 +964,7 @@ describe('ol.View', function() {
       expect(view.getZoom()).to.be(5);
 
       view.setResolution(15);
-      expect(view.getZoom()).to.be(undefined);
+      expect(view.getZoom()).to.roughlyEqual(Math.log(512 / 15) / Math.LN2, 1e-9);
     });
 
     it('works for resolution arrays with variable zoom factors', function() {
@@ -1070,6 +1068,8 @@ describe('ol.View', function() {
       expect(view.getZoomForResolution(max / 2)).to.be(1);
 
       expect(view.getZoomForResolution(max / 4)).to.be(2);
+
+      expect(view.getZoomForResolution(2 * max)).to.be(-1);
     });
 
     it('returns correct zoom levels for specifically configured resolutions', function() {