Method updateScrollPosition

src/dd-draggable.ts:432–440

@internal starts or continues auto-scroll when the dragged helper is clipped by the scroll container. * Takes the grid's own element to find the scroll container so external/sidebar drags work too (#2074).

(gridEl: HTMLElement)

  /** @internal starts or continues auto-scroll when the dragged helper is clipped by the scroll container.
   * Takes the grid's own element to find the scroll container so external/sidebar drags work too (#2074). */
   public updateScrollPosition(gridEl: HTMLElement): void {
    this._autoScrollContainer = Utils.getScrollElement(gridEl); // always use latest active grid
    const clipping = this._getClipping(this.helper, this._autoScrollContainer);
    if (clipping === 0) {
      this._stopScrolling();
    } else if (!this._autoScrollAnimId) {
      this._autoScrollAnimId = requestAnimationFrame(this._autoScrollTick);
    }
  }

  /** @internal compute how many pixels the element is clipped: negative = above, positive = below, 0 = fully inside OR outside (stop scrolling) */
  protected _getClipping(el: HTMLElement, scrollEl: HTMLElement): number {