gecko/layout/generic/nsAbsoluteContainingBlock.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2012-05-21 04:12:37 -07:00
/* 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/. */
/*
* 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 "nsIFrame.h"
class nsContainerFrame;
struct nsHTMLReflowState;
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 (kAbsoluteList or kFixedList).
*
* All functions include as the first argument the frame that is delegating
* the request.
*/
class nsAbsoluteContainingBlock
{
public:
typedef nsIFrame::ChildListID ChildListID;
explicit nsAbsoluteContainingBlock(ChildListID aChildListID)
#ifdef DEBUG
: mChildListID(aChildListID)
#endif
{
MOZ_ASSERT(mChildListID == nsIFrame::kAbsoluteList ||
mChildListID == nsIFrame::kFixedList,
"should either represent position:fixed or absolute content");
}
const nsFrameList& GetChildList() const { return mAbsoluteFrames; }
void AppendChildList(nsTArray<nsIFrame::ChildList>* aLists,
ChildListID aListID) const
{
NS_ASSERTION(aListID == mChildListID, "wrong list ID");
GetChildList().AppendIfNonempty(aLists, aListID);
}
void SetInitialChildList(nsIFrame* aDelegatingFrame,
ChildListID aListID,
nsFrameList& aChildList);
void AppendFrames(nsIFrame* aDelegatingFrame,
ChildListID aListID,
nsFrameList& aFrameList);
void InsertFrames(nsIFrame* aDelegatingFrame,
ChildListID aListID,
nsIFrame* aPrevFrame,
nsFrameList& aFrameList);
void RemoveFrame(nsIFrame* aDelegatingFrame,
ChildListID aListID,
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.
*
* @param aOverflowAreas, if non-null, is unioned with (in the local
* coordinate space) the overflow areas of the absolutely positioned
* children.
*
* @param aReflowStatus is assumed to be already-initialized, e.g. with the
* status of the delegating frame's main reflow. This function merges in the
* statuses of the absolutely positioned children's reflows.
*/
void Reflow(nsContainerFrame* aDelegatingFrame,
nsPresContext* aPresContext,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aReflowStatus,
const nsRect& aContainingBlock,
bool aConstrainHeight,
bool aCBWidthChanged,
bool aCBHeightChanged,
nsOverflowAreas* aOverflowAreas);
void DestroyFrames(nsIFrame* aDelegatingFrame,
nsIFrame* aDestructRoot);
bool HasAbsoluteFrames() const { return mAbsoluteFrames.NotEmpty(); }
/**
* Mark our size-dependent absolute frames with NS_FRAME_HAS_DIRTY_CHILDREN
* so that we'll make sure to reflow them.
*/
void MarkSizeDependentFramesDirty();
/**
* Mark all our absolute frames with NS_FRAME_IS_DIRTY.
*/
void MarkAllFramesDirty();
protected:
/**
* Returns true if the position of aFrame depends on the position of
* its placeholder or if the position or size of aFrame depends on a
* containing block dimension that changed.
*/
bool FrameDependsOnContainer(nsIFrame* aFrame, bool aCBWidthChanged,
bool aCBHeightChanged);
void ReflowAbsoluteFrame(nsIFrame* aDelegatingFrame,
nsPresContext* aPresContext,
const nsHTMLReflowState& aReflowState,
const nsRect& aContainingBlockRect,
bool aConstrainHeight,
nsIFrame* aKidFrame,
nsReflowStatus& aStatus,
nsOverflowAreas* aOverflowAreas);
/**
* Mark our absolute frames dirty.
* @param aMarkAllDirty if true, all will be marked with NS_FRAME_IS_DIRTY.
* Otherwise, the size-dependant ones will be marked with
* NS_FRAME_HAS_DIRTY_CHILDREN.
*/
void DoMarkFramesDirty(bool aMarkAllDirty);
protected:
nsFrameList mAbsoluteFrames; // additional named child list
#ifdef DEBUG
ChildListID const mChildListID; // kFixedList or kAbsoluteList
#endif
};
#endif /* nsnsAbsoluteContainingBlock_h___ */