gecko/layout/generic/nsAbsoluteContainingBlock.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* code for managing absolutely positioned children of a rendering
* object that is a containing block for them
*/
#ifndef nsAbsoluteContainingBlock_h___
#define nsAbsoluteContainingBlock_h___
#include "nsFrameList.h"
#include "nsHTMLReflowState.h"
#include "nsGkAtoms.h"
#include "nsContainerFrame.h"
class nsIAtom;
class nsIFrame;
class nsPresContext;
/**
* This class contains the logic for being an absolute containing block. This
* class is used within viewport frames (for frames representing content with
* fixed position) and blocks (for frames representing absolutely positioned
* content), since each set of frames is absolutely positioned with respect to
* its parent.
*
* There is no principal child list, just a named child list which contains
* the absolutely positioned frames.
*
* All functions include as the first argument the frame that is delegating
* the request.
*
* @see nsGkAtoms::absoluteList and nsGkAtoms::fixedList
*/
class nsAbsoluteContainingBlock
{
public:
nsAbsoluteContainingBlock(nsIAtom* aChildListName)
#ifdef DEBUG
: mChildListName(aChildListName)
#endif
{
NS_ASSERTION(mChildListName == nsGkAtoms::absoluteList ||
mChildListName == nsGkAtoms::fixedList,
"should either represent position:fixed or absolute content");
}
#ifdef DEBUG
nsIAtom* GetChildListName() const { return mChildListName; }
#endif
nsIFrame* GetFirstChild() const { return mAbsoluteFrames.FirstChild(); }
nsresult SetInitialChildList(nsIFrame* aDelegatingFrame,
nsIAtom* aListName,
nsIFrame* aChildList);
nsresult AppendFrames(nsIFrame* aDelegatingFrame,
nsIAtom* aListName,
nsIFrame* aFrameList);
nsresult InsertFrames(nsIFrame* aDelegatingFrame,
nsIAtom* aListName,
nsIFrame* aPrevFrame,
nsIFrame* aFrameList);
nsresult RemoveFrame(nsIFrame* aDelegatingFrame,
nsIAtom* aListName,
nsIFrame* aOldFrame);
// Called by the delegating frame after it has done its reflow first. This
// function will reflow any absolutely positioned child frames that need to
// be reflowed, e.g., because the absolutely positioned child frame has
// 'auto' for an offset, or a percentage based width or height.
// If aChildBounds is set, it returns (in the local coordinate space) the
// bounding rect of the absolutely positioned child elements taking into
// account their overflow area (if it is visible).
// @param aForceReflow if this is false, reflow for some absolutely
// positioned frames may be skipped based on whether they use
// placeholders for positioning and on whether the containing block
// width or height changed.
nsresult Reflow(nsContainerFrame* aDelegatingFrame,
nsPresContext* aPresContext,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aReflowStatus,
nscoord aContainingBlockWidth,
nscoord aContainingBlockHeight,
PRBool aConstrainHeight,
PRBool aCBWidthChanged,
PRBool aCBHeightChanged,
nsRect* aChildBounds = nsnull);
void DestroyFrames(nsIFrame* aDelegatingFrame);
PRBool HasAbsoluteFrames() {return mAbsoluteFrames.NotEmpty();}
protected:
// Returns PR_TRUE if the position of f depends on the position of
// its placeholder or if the position or size of f depends on a
// containing block dimension that changed.
PRBool FrameDependsOnContainer(nsIFrame* f, PRBool aCBWidthChanged,
PRBool aCBHeightChanged);
nsresult ReflowAbsoluteFrame(nsIFrame* aDelegatingFrame,
nsPresContext* aPresContext,
const nsHTMLReflowState& aReflowState,
nscoord aContainingBlockWidth,
nscoord aContainingBlockHeight,
PRBool aConstrainHeight,
nsIFrame* aKidFrame,
nsReflowStatus& aStatus,
nsRect* aChildBounds);
protected:
nsFrameList mAbsoluteFrames; // additional named child list
#ifdef DEBUG
nsIAtom* const mChildListName; // nsGkAtoms::fixedList or nsGkAtoms::absoluteList
// helper routine for debug printout
void PrettyUC(nscoord aSize,
char* aBuf);
#endif
};
#endif /* nsnsAbsoluteContainingBlock_h___ */