gecko-dev/layout/xul/nsStackFrame.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

//
// 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(aContext);
}

NS_IMPL_FRAMEARENA_HELPERS(nsStackFrame)

nsStackFrame::nsStackFrame(nsStyleContext* aContext):
  nsBoxFrame(aContext, kClassID)
{
  nsCOMPtr<nsBoxLayout> layout;
  NS_NewStackLayout(layout);
  SetXULLayoutManager(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.
void
nsStackFrame::BuildDisplayListForChildren(nsDisplayListBuilder*   aBuilder,
                                          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.
    BuildDisplayListForChild(aBuilder, kid, kidLists, DISPLAY_CHILD_FORCE_STACKING_CONTEXT);
    kid = kid->GetNextSibling();
  }
}