Merge pull request #5099 from AnalyticalGraphicsInc/pin-builder-alpha

Fix leaky alpha values coming from pinBuilder

CHANGES.md

@@ -8,6 +8,7 @@ Change Log
 * Fix crunch compressed textures in IE11. [#5057](https://github.com/AnalyticalGraphicsInc/cesium/pull/5057)
 * Fixed a bug in `Quaternion.fromHeadingPitchRoll` that made it erroneously throw an exception when passed individual angles in an unminified / debug build.
 * Fix `GroundPrimitive` rendering in 2D and Columbus View [#5078](https://github.com/AnalyticalGraphicsInc/cesium/pull/5078)
+* Fixed an issue with `PinBuilder` where inset images could have low-alpha fringes against an opaque background.  [#5099](https://github.com/AnalyticalGraphicsInc/cesium/pull/5099)
 * Fixed a bug in `ModelAnimationCache` causing different animations to reference the same animation. [#5064](https://github.com/AnalyticalGraphicsInc/cesium/pull/5064)
 
 ### 1.31 - 2017-03-01

Source/Core/PinBuilder.js

@@ -171,8 +171,8 @@ define([
         }
 
         //x and y are the center of the pin box
-        var x = (size - sizeX) / 2;
-        var y = ((7 / 24) * size) - (sizeY / 2);
+        var x = Math.round((size - sizeX) / 2);
+        var y = Math.round(((7 / 24) * size) - (sizeY / 2));
 
         context2D.globalCompositeOperation = 'destination-out';
         context2D.drawImage(image, x - 1, y, sizeX, sizeY);
@@ -182,14 +182,14 @@ define([
 
         context2D.globalCompositeOperation = 'destination-over';
         context2D.fillStyle = Color.BLACK.toCssColorString();
-        context2D.fillRect(x - 1, y - 1, sizeX + 1, sizeY + 1);
+        context2D.fillRect(x - 1, y - 1, sizeX + 2, sizeY + 2);
 
         context2D.globalCompositeOperation = 'destination-out';
         context2D.drawImage(image, x, y, sizeX, sizeY);
 
         context2D.globalCompositeOperation = 'destination-over';
         context2D.fillStyle = Color.WHITE.toCssColorString();
-        context2D.fillRect(x, y, sizeX, sizeY);
+        context2D.fillRect(x - 1, y - 2, sizeX + 2, sizeY + 2);
     }
 
     var stringifyScratch = new Array(4);