pjs/layout/generic/nsPlaceholderFrame.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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* 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
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*
* 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
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#ifndef nsPlaceholderFrame_h___
#define nsPlaceholderFrame_h___
#include "nsSplittableFrame.h"
#include "nsLayoutAtoms.h"
nsresult NS_NewPlaceholderFrame(nsIPresShell* aPresShell, nsIFrame** aInstancePtrResult);
/**
* Implementation of a frame that's used as a placeholder for a frame that
* has been moved out of the flow
*/
class nsPlaceholderFrame : public nsSplittableFrame {
public:
/**
* Create a new placeholder frame
*/
friend nsresult NS_NewPlaceholderFrame(nsIPresShell* aPresShell, nsIFrame** aInstancePtrResult);
nsPlaceholderFrame();
virtual ~nsPlaceholderFrame();
// Get/Set the associated out of flow frame
nsIFrame* GetOutOfFlowFrame() const {return mOutOfFlowFrame;}
void SetOutOfFlowFrame(nsIFrame* aFrame) {mOutOfFlowFrame = aFrame;}
// nsIHTMLReflow overrides
NS_IMETHOD Reflow(nsPresContext* aPresContext,
nsHTMLReflowMetrics& aDesiredSize,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aStatus);
NS_IMETHOD Destroy(nsPresContext* aPresContext);
// nsIFrame overrides
#ifdef DEBUG
NS_IMETHOD Paint(nsPresContext* aPresContext,
nsIRenderingContext& aRenderingContext,
const nsRect& aDirtyRect,
nsFramePaintLayer aWhichLayer,
PRUint32 aFlags = 0);
NS_IMETHOD List(FILE* out, PRInt32 aIndent) const;
#endif
/**
* Get the "type" of the frame
*
* @see nsLayoutAtoms::placeholderFrame
*/
virtual nsIAtom* GetType() const;
#ifdef DEBUG
NS_IMETHOD GetFrameName(nsAString& aResult) const;
#endif
virtual PRBool IsEmpty() { return PR_TRUE; }
virtual PRBool IsSelfEmpty() { return PR_TRUE; }
/**
* @return the out-of-flow for aFrame if aFrame is a placeholder; otherwise
* aFrame
*/
static nsIFrame* GetRealFrameFor(nsIFrame* aFrame) {
NS_PRECONDITION(aFrame, "Must have a frame to work with");
if (aFrame->GetType() == nsLayoutAtoms::placeholderFrame) {
return GetRealFrameForPlaceholder(aFrame);
}
return aFrame;
}
/**
* @return the out-of-flow for aFrame, which is known to be a placeholder
*/
static nsIFrame* GetRealFrameForPlaceholder(nsIFrame* aFrame) {
NS_PRECONDITION(aFrame->GetType() == nsLayoutAtoms::placeholderFrame,
"Must have placeholder frame as input");
nsIFrame* outOfFlow =
NS_STATIC_CAST(nsPlaceholderFrame*, aFrame)->GetOutOfFlowFrame();
NS_ASSERTION(outOfFlow, "Null out-of-flow for placeholder?");
return outOfFlow;
}
protected:
nsIFrame* mOutOfFlowFrame;
};
#endif /* nsPlaceholderFrame_h___ */