Merge pull request #3711 from marcjansen/color

Fix and test ol.color.blend

src/ol/color/color.js

@@ -64,12 +64,12 @@ ol.color.blend = function(dst, src, opt_color) {
   // FIXME do we need to scale by 255?
   var out = goog.isDef(opt_color) ? opt_color : [];
   var dstA = dst[3];
-  var srcA = dst[3];
+  var srcA = src[3];
   if (dstA == 1) {
     out[0] = (src[0] * srcA + dst[0] * (1 - srcA) + 0.5) | 0;
     out[1] = (src[1] * srcA + dst[1] * (1 - srcA) + 0.5) | 0;
     out[2] = (src[2] * srcA + dst[2] * (1 - srcA) + 0.5) | 0;
-    out[4] = 1;
+    out[3] = 1;
   } else if (srcA === 0) {
     out[0] = dst[0];
     out[1] = dst[1];

test/spec/ol/color.test.js

@@ -3,6 +3,33 @@ goog.provide('ol.test.color');
 
 describe('ol.color', function() {
 
+  describe('ol.color.blend', function() {
+    it('blends red (a=1) and blue (a=1) to blue (a=1)', function() {
+      var red = [255, 0, 0, 1];
+      var blue = [0, 0, 255, 1];
+      var blended = ol.color.blend(red, blue);
+      expect(blended).to.eql([0, 0, 255, 1]);
+    });
+    it('blends red (a=1) and blue (a=0) to red (a=1)', function() {
+      var red = [255, 0, 0, 1];
+      var blue = [0, 0, 255, 0];
+      var blended = ol.color.blend(red, blue);
+      expect(blended).to.eql([255, 0, 0, 1]);
+    });
+    it('blends red (a=0.5) and blue (a=0.5) to purple (a=0.75)', function() {
+      var red = [255, 0, 0, 0.5];
+      var blue = [0, 0, 255, 0.5];
+      var blended = ol.color.blend(red, blue);
+      expect(blended).to.eql([85, 0, 170, 0.75]);
+    });
+    it('blends red (a=0.5) and blue (a=0) to red (a=0.5)', function() {
+      var red = [255, 0, 0, 0.5];
+      var blue = [0, 0, 255, 0];
+      var blended = ol.color.blend(red, blue);
+      expect(blended).to.eql([255, 0, 0, 0.5]);
+    });
+  });
+
   describe('ol.color.fromString', function() {
 
     before(function() {