C++ nsDisplayListSet::PositionedDescendants方法代码示例

void
ViewportFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                const nsRect&           aDirtyRect,
                                const nsDisplayListSet& aLists)
{
  PROFILER_LABEL("ViewportFrame", "BuildDisplayList",
    js::ProfileEntry::Category::GRAPHICS);

  if (nsIFrame* kid = mFrames.FirstChild()) {
    // make the kid's BorderBackground our own. This ensures that the canvas
    // frame's background becomes our own background and therefore appears
    // below negative z-index elements.
    BuildDisplayListForChild(aBuilder, kid, aDirtyRect, aLists);
  }

  nsDisplayList topLayerList;
  BuildDisplayListForTopLayer(aBuilder, &topLayerList);
  if (!topLayerList.IsEmpty()) {
    // Wrap the whole top layer in a single item with maximum z-index,
    // and append it at the very end, so that it stays at the topmost.
    nsDisplayWrapList* wrapList =
      new (aBuilder) nsDisplayWrapList(aBuilder, this, &topLayerList);
    wrapList->SetOverrideZIndex(
      std::numeric_limits<decltype(wrapList->ZIndex())>::max());
    aLists.PositionedDescendants()->AppendNewToTop(wrapList);
  }
}

void
nsGridContainerFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                       const nsRect&           aDirtyRect,
                                       const nsDisplayListSet& aLists)
{
  DisplayBorderBackgroundOutline(aBuilder, aLists);

  // Our children are all grid-level boxes, which behave the same as
  // inline-blocks in painting, so their borders/backgrounds all go on
  // the BlockBorderBackgrounds list.
  // Also, we capture positioned descendants so we can sort them by
  // CSS 'order'.
  nsDisplayList positionedDescendants;
  nsDisplayListSet childLists(aLists.BlockBorderBackgrounds(),
                              aLists.BlockBorderBackgrounds(),
                              aLists.Floats(),
                              aLists.Content(),
                              &positionedDescendants,
                              aLists.Outlines());
  typedef GridItemCSSOrderIterator::OrderState OrderState;
  OrderState order = mIsNormalFlowInCSSOrder ? OrderState::eKnownOrdered
                                             : OrderState::eKnownUnordered;
  GridItemCSSOrderIterator iter(this, kPrincipalList, order);
  for (; !iter.AtEnd(); iter.Next()) {
    nsIFrame* child = *iter;
    BuildDisplayListForChild(aBuilder, child, aDirtyRect, childLists,
                             ::GetDisplayFlagsForGridItem(child));
  }
  positionedDescendants.SortByCSSOrder(aBuilder);
  aLists.PositionedDescendants()->AppendToTop(&positionedDescendants);
}

nsresult nsDisplayWrapper::WrapLists(nsDisplayListBuilder* aBuilder,
    nsIFrame* aFrame, const nsDisplayListSet& aIn, const nsDisplayListSet& aOut)
{
  nsresult rv = WrapListsInPlace(aBuilder, aFrame, aIn);
  NS_ENSURE_SUCCESS(rv, rv);

  if (&aOut == &aIn)
    return NS_OK;
  aOut.BorderBackground()->AppendToTop(aIn.BorderBackground());
  aOut.BlockBorderBackgrounds()->AppendToTop(aIn.BlockBorderBackgrounds());
  aOut.Floats()->AppendToTop(aIn.Floats());
  aOut.Content()->AppendToTop(aIn.Content());
  aOut.PositionedDescendants()->AppendToTop(aIn.PositionedDescendants());
  aOut.Outlines()->AppendToTop(aIn.Outlines());
  return NS_OK;
}

void nsDisplayListSet::MoveTo(const nsDisplayListSet& aDestination) const
{
  aDestination.BorderBackground()->AppendToTop(BorderBackground());
  aDestination.BlockBorderBackgrounds()->AppendToTop(BlockBorderBackgrounds());
  aDestination.Floats()->AppendToTop(Floats());
  aDestination.Content()->AppendToTop(Content());
  aDestination.PositionedDescendants()->AppendToTop(PositionedDescendants());
  aDestination.Outlines()->AppendToTop(Outlines());
}

void
nsFrame::PrintDisplayListSet(nsDisplayListBuilder* aBuilder,
                             const nsDisplayListSet& aSet,
                             std::stringstream& aStream,
                             bool aDumpHtml)
{
  if (aDumpHtml) {
    aStream << "<ul>";
  }
  PrintDisplayListSetItem(aBuilder, "[BorderBackground]", *(aSet.BorderBackground()), aStream, aDumpHtml);
  PrintDisplayListSetItem(aBuilder, "[BlockBorderBackgrounds]", *(aSet.BlockBorderBackgrounds()), aStream, aDumpHtml);
  PrintDisplayListSetItem(aBuilder, "[Floats]", *(aSet.Floats()), aStream, aDumpHtml);
  PrintDisplayListSetItem(aBuilder, "[PositionedDescendants]", *(aSet.PositionedDescendants()), aStream, aDumpHtml);
  PrintDisplayListSetItem(aBuilder, "[Outlines]", *(aSet.Outlines()), aStream, aDumpHtml);
  PrintDisplayListSetItem(aBuilder, "[Content]", *(aSet.Content()), aStream, aDumpHtml);
  if (aDumpHtml) {
    aStream << "</ul>";
  }
}

nsresult nsDisplayWrapper::WrapListsInPlace(nsDisplayListBuilder* aBuilder,
    nsIFrame* aFrame, const nsDisplayListSet& aLists)
{
  nsresult rv;
  if (WrapBorderBackground()) {
    // Our border-backgrounds are in-flow
    rv = WrapDisplayList(aBuilder, aFrame, aLists.BorderBackground(), this);
    NS_ENSURE_SUCCESS(rv, rv);
  }
  // Our block border-backgrounds are in-flow
  rv = WrapDisplayList(aBuilder, aFrame, aLists.BlockBorderBackgrounds(), this);
  NS_ENSURE_SUCCESS(rv, rv);
  // The floats are not in flow
  rv = WrapEachDisplayItem(aBuilder, aLists.Floats(), this);
  NS_ENSURE_SUCCESS(rv, rv);
  // Our child content is in flow
  rv = WrapDisplayList(aBuilder, aFrame, aLists.Content(), this);
  NS_ENSURE_SUCCESS(rv, rv);
  // The positioned descendants may not be in-flow
  rv = WrapEachDisplayItem(aBuilder, aLists.PositionedDescendants(), this);
  NS_ENSURE_SUCCESS(rv, rv);
  // The outlines may not be in-flow
  return WrapEachDisplayItem(aBuilder, aLists.Outlines(), this);
}