Get the in-use scroll-offset.
function _calcScrollOffset(normalize, refreshParticle) {

        // When moving using touch-gestures, make the offset stick to the
        // finger. When the bounds is exceeded, decrease the scroll distance
        // by two.
        if (refreshParticle || (this._scroll.particleValue === undefined)) {
            this._scroll.particleValue = this._scroll.particle.getPosition1D();
            this._scroll.particleValue = Math.round(this._scroll.particleValue * 1000) / 1000;
        }

        // do stuff
        var scrollOffset = this._scroll.particleValue;
        if (this._scroll.scrollDelta || this._scroll.normalizedScrollDelta) {
            scrollOffset += this._scroll.scrollDelta + this._scroll.normalizedScrollDelta;
            if (((this._scroll.boundsReached & Bounds.PREV) && (scrollOffset > this._scroll.springPosition)) ||
               ((this._scroll.boundsReached & Bounds.NEXT) && (scrollOffset < this._scroll.springPosition)) ||
               (this._scroll.boundsReached === Bounds.BOTH)) {
                scrollOffset = this._scroll.springPosition;
            }
            if (normalize) {
                if (!this._scroll.scrollDelta) {
                    this._scroll.normalizedScrollDelta = 0;
                    _setParticle.call(this, scrollOffset, undefined, '_calcScrollOffset');
                }
                this._scroll.normalizedScrollDelta += this._scroll.scrollDelta;
                this._scroll.scrollDelta = 0;
            }
        }

        if (this._scroll.scrollForceCount && this._scroll.scrollForce) {
            if (this._scroll.springPosition !== undefined) {
                scrollOffset = (scrollOffset + this._scroll.scrollForce + this._scroll.springPosition) / 2.0;
            }
            else {
                scrollOffset += this._scroll.scrollForce;
            }
        }

        // Prevent the scroll position from exceeding the bounds when overscroll is disabled
        if (!this.options.overscroll) {
            if ((this._scroll.boundsReached === Bounds.BOTH) ||
                ((this._scroll.boundsReached === Bounds.PREV) && (scrollOffset > this._scroll.springPosition)) ||
                ((this._scroll.boundsReached === Bounds.NEXT) && (scrollOffset < this._scroll.springPosition))) {
                scrollOffset = this._scroll.springPosition;
            }
        }

        //_log.call(this, 'scrollOffset: ', scrollOffset, ', particle:', this._scroll.particle.getPosition1D(), ', moveToPosition: ', this._scroll.moveToPosition, ', springPosition: ', this._scroll.springPosition);
        return scrollOffset;
    }