Merge pull request #3964 from rattai/imagewms_extent

Compute new image extent for comparison to existing image extent

src/ol/source/imagewmssource.js

@@ -92,6 +92,12 @@ ol.source.ImageWMS = function(opt_options) {
    */
   this.image_ = null;
 
+  /**
+   * @private
+   * @type {ol.Extent}
+   */
+  this.imageExtent_ = null;
+
   /**
    * @private
    * @type {ol.Size}
@@ -203,7 +209,7 @@ ol.source.ImageWMS.prototype.getImage =
       this.renderedRevision_ == this.getRevision() &&
       image.getResolution() == resolution &&
       image.getPixelRatio() == pixelRatio &&
-      ol.extent.containsExtent(image.getExtent(), extent)) {
+      ol.extent.containsExtent(image.getExtent(), this.imageExtent_)) {
     return image;
   }
 
@@ -240,6 +246,8 @@ ol.source.ImageWMS.prototype.getImage =
   extent[1] = centerY - imageResolution * height / 2;
   extent[3] = centerY + imageResolution * height / 2;
 
+  this.imageExtent_ = extent;
+
   this.imageSize_[0] = width;
   this.imageSize_[1] = height;
 
@@ -362,6 +370,7 @@ ol.source.ImageWMS.prototype.setUrl = function(url) {
   if (url != this.url_) {
     this.url_ = url;
     this.image_ = null;
+    this.imageExtent_ = null;
     this.changed();
   }
 };
@@ -376,6 +385,7 @@ ol.source.ImageWMS.prototype.updateParams = function(params) {
   goog.object.extend(this.params_, params);
   this.updateV13_();
   this.image_ = null;
+  this.imageExtent_ = null;
   this.changed();
 };
 

test/spec/ol/source/imagewmssource.test.js

@@ -155,6 +155,14 @@ describe('ol.source.ImageWMS', function() {
       expect(imageLoadFunction.calledWith(image, image.src_)).to.be(true);
     });
 
+    it('returns same image for consecutive calls with same args', function() {
+      var extent = [10.01, 20, 30.01, 40];
+      var source = new ol.source.ImageWMS(options);
+      var image1 = source.getImage(extent, resolution, pixelRatio, projection);
+      var image2 = source.getImage(extent, resolution, pixelRatio, projection);
+      expect(image1).to.equal(image2);
+    });
+
   });
 
   describe('#getGetFeatureInfo', function() {