fix(scale option): Fix Slider goes back when moved and scaled

close #346

demo/demo.js

@@ -13,7 +13,6 @@ app.controller('MainCtrl', function($scope, $rootScope, $timeout, $modal) {
     options: {
       floor: 0,
       ceil: 100,
-      rightToLeft: true,
       step: 1
     }
   };

dist/rzslider.js

 /*! angularjs-slider - v5.7.0 - 
  (c) Rafal Zajac <rzajac@gmail.com>, Valentin Hervieu <valentin@hervieu.me>, Jussi Saarivirta <jusasi@gmail.com>, Angelin Sirbu <angelin.sirbu@gmail.com> - 
  https://github.com/angular-slider/angularjs-slider - 
- 2016-10-16 */
+ 2016-10-22 */
 /*jslint unparam: true */
 /*global angular: false, console: false, define, module */
 (function(root, factory) {
@@ -1526,7 +1526,7 @@
           eventPos = -this.getEventXY(event) + sliderPos;
         else
           eventPos = this.getEventXY(event) - sliderPos;
-        return (eventPos - this.handleHalfDim) * this.options.scale;
+        return eventPos * this.options.scale  - this.handleHalfDim; // #346 handleHalfDim is already scaled
       },
 
       /**

src/rzslider.js

@@ -1530,7 +1530,7 @@
           eventPos = -this.getEventXY(event) + sliderPos;
         else
           eventPos = this.getEventXY(event) - sliderPos;
-        return (eventPos - this.handleHalfDim) * this.options.scale;
+        return eventPos * this.options.scale  - this.handleHalfDim; // #346 handleHalfDim is already scaled
       },
 
       /**

tests/specs/helper-functions-test.js

@@ -341,7 +341,7 @@
         helper.slider.sliderElem.rzsp = 10;
         helper.slider.handleHalfDim = 16;
 
-        expect(helper.slider.getEventPosition(event)).to.equal(10);
+        expect(helper.slider.getEventPosition(event)).to.equal(2);
       });
 
       it('should have a valid getEventPosition for vertical sliders with scale option', function() {
@@ -355,7 +355,7 @@
         helper.slider.sliderElem.rzsp = 10;
         helper.slider.handleHalfDim = 16;
 
-        expect(helper.slider.getEventPosition(event)).to.equal(-26);
+        expect(helper.slider.getEventPosition(event)).to.equal(-34);
       });
 
       it('should have a valid getEventNames for desktop', function() {