C++ (Cpp) PaintLayer::getScrollableArea示例

void PaintPropertyTreeBuilder::updateScrollTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
{
    if (!object.isBoxModelObject() || !object.hasOverflowClip())
        return;

    PaintLayer* layer = toLayoutBoxModelObject(object).layer();
    ASSERT(layer);
    DoubleSize scrollOffset = layer->getScrollableArea()->scrollOffset();
    if (scrollOffset.isZero() && !layer->scrollsOverflow())
        return;

    RefPtr<TransformPaintPropertyNode> scrollTranslation = TransformPaintPropertyNode::create(
        TransformationMatrix().translate(-scrollOffset.width(), -scrollOffset.height()),
        FloatPoint3D(),
        context.currentTransform);
    context.currentTransform = scrollTranslation.get();
    object.getMutableForPainting().ensureObjectPaintProperties().setScrollTranslation(scrollTranslation.release());
}

示例#2

显示文件

void ScrollAnchor::clear() {
  LayoutObject* layoutObject =
      m_anchorObject ? m_anchorObject : scrollerLayoutBox(m_scroller);
  PaintLayer* layer = nullptr;
  if (LayoutObject* parent = layoutObject->parent())
    layer = parent->enclosingLayer();

  // Walk up the layer tree to clear any scroll anchors.
  while (layer) {
    if (PaintLayerScrollableArea* scrollableArea = layer->getScrollableArea()) {
      ScrollAnchor* anchor = scrollableArea->scrollAnchor();
      DCHECK(anchor);
      anchor->clearSelf();
    }
    layer = layer->parent();
  }

  if (FrameView* view = layoutObject->frameView()) {
    ScrollAnchor* anchor = view->scrollAnchor();
    DCHECK(anchor);
    anchor->clearSelf();
  }
}