collapsedMarginBottom property

Implementation

double get collapsedMarginBottom {
  double marginBottom;

  // Margin is invalid for inline element.
  if (effectiveDisplay == CSSDisplay.inline) {
    marginBottom = 0;
    return marginBottom;
  }

  // Margin collapse does not work on following case:
  // 1. Document root element(HTML)
  // 2. Inline level elements
  // 3. Inner renderBox of element with overflow auto/scroll
  if (isDocumentRootBox() || (effectiveDisplay != CSSDisplay.block && effectiveDisplay != CSSDisplay.flex)) {
    marginBottom = this.marginBottom.computedValue;
    return marginBottom;
  }

  if (!isNextSiblingAreRenderObject()) {
    // Margin bottom collapse with its parent if it is the last child of its parent and its value is 0.
    marginBottom = _collapsedMarginBottomWithParent;
  } else {
    // Margin bottom collapse with its nested last child when meeting following cases at the same time:
    // 1. No padding, border is set.
    // 2. No height, min-height, max-height is set.
    // 3. No block formatting context of itself (eg. overflow scroll and position absolute) is created.
    marginBottom = _collapsedMarginBottomWithLastChild;
  }

  return marginBottom;
}