code: function() {
          this._worldWidthTarget = this._scaleSpring.target.value;
          this._worldHeightTarget = this.normHeight * this._scaleSpring.target.value;
          this._worldWidthCurrent = this._scaleSpring.current.value;
          this._worldHeightCurrent = this.normHeight * this._scaleSpring.current.value;
      }
docs: private