gecko/layout/xul/base/src/nsStackFrame.cpp

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//
// Eric Vaughan
// Netscape Communications
//
// See documentation in associated header file
//

#include "nsStackFrame.h"
#include "nsStyleContext.h"
#include "nsIContent.h"
#include "nsCOMPtr.h"
#include "nsHTMLParts.h"
#include "nsIPresShell.h"
#include "nsCSSRendering.h"
#include "nsBoxLayoutState.h"
#include "nsStackLayout.h"
#include "nsDisplayList.h"

nsIFrame*
NS_NewStackFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
  return new (aPresShell) nsStackFrame(aPresShell, aContext);
}

NS_IMPL_FRAMEARENA_HELPERS(nsStackFrame)

nsStackFrame::nsStackFrame(nsIPresShell* aPresShell, nsStyleContext* aContext):
  nsBoxFrame(aPresShell, aContext)
{
  nsCOMPtr<nsBoxLayout> layout;
  NS_NewStackLayout(aPresShell, layout);
  SetLayoutManager(layout);
}

// REVIEW: The old code put everything in the background layer. To be more
// consistent with the way other frames work, I'm putting everything in the
// Content() (i.e., foreground) layer (see nsFrame::BuildDisplayListForChild,
// the case for stacking context but non-positioned, non-floating frames).
// This could easily be changed back by hacking nsBoxFrame::BuildDisplayListInternal
// a bit more.
NS_IMETHODIMP
nsStackFrame::BuildDisplayListForChildren(nsDisplayListBuilder*   aBuilder,
                                          const nsRect&           aDirtyRect,
                                          const nsDisplayListSet& aLists)
{
  // BuildDisplayListForChild puts stacking contexts into the PositionedDescendants
  // list. So we need to map that list to aLists.Content(). This is an easy way to
  // do that.
  nsDisplayList* content = aLists.Content();
  nsDisplayListSet kidLists(content, content, content, content, content, content);
  nsIFrame* kid = mFrames.FirstChild();
  while (kid) {
    // Force each child into its own true stacking context.
    nsresult rv =
      BuildDisplayListForChild(aBuilder, kid, aDirtyRect, kidLists,
                               DISPLAY_CHILD_FORCE_STACKING_CONTEXT);
    NS_ENSURE_SUCCESS(rv, rv);
    kid = kid->GetNextSibling();
  }
  return NS_OK;
}