ZoomLensInterpolation = function(lensPos, lensStrength) {
            this.leftImpl = new CircularInterpolation();
            this.rightImpl = new CircularInterpolation();
            this.lensPos = lensPos || 0.5;
            this.lensStrength = lensStrength || 1;
            this.absStrength = Math.abs(this.lensStrength);
            this.leftImpl.setFlipped(this.lensStrength > 0);
            this.rightImpl.setFlipped(this.lensStrength < 0);
          }
@class This class provides an adjustable zoom lens to either bundle or dilate values
around a focal point within a given interval. For a example use cases, please
have a look at the provided ScaleMapDataViz and ZoomLens examples.
@member toxi