Method _getClipping

src/dd-draggable.ts:443–453

@internal compute how many pixels the element is clipped: negative = above, positive = below, 0 = fully inside OR outside (stop scrolling)

(el: HTMLElement, scrollEl: HTMLElement)

  /** @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 {
    const elRect = el.getBoundingClientRect();
    const scrollRect = scrollEl.getBoundingClientRect();
    const viewportH = window.innerHeight || document.documentElement.clientHeight;
    if (elRect.bottom < scrollRect.top || elRect.top > scrollRect.bottom) return 0; // fully outside
    const clippedBelow = elRect.bottom - Math.min(scrollRect.bottom, viewportH);
    const clippedAbove = elRect.top - Math.max(scrollRect.top, 0);
    if (clippedAbove < 0) return clippedAbove;
    if (clippedBelow > 0) return clippedBelow;
    return 0;
  }

  /** @internal single tick of the auto-scroll animation loop */
  protected _autoScrollTick = (): void => {