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nsAbsoluteContainingBlock.h
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00001 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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00037 #ifndef nsAbsoluteContainingBlock_h___
00038 #define nsAbsoluteContainingBlock_h___
00039 
00040 #include "nsFrameList.h"
00041 #include "nsHTMLReflowState.h"
00042 #include "nsLayoutAtoms.h"
00043 
00044 class nsIAtom;
00045 class nsIFrame;
00046 class nsPresContext;
00047 
00059 class nsAbsoluteContainingBlock
00060 {
00061 public:
00062   nsAbsoluteContainingBlock() { }          // useful for debugging
00063 
00064   virtual ~nsAbsoluteContainingBlock() { } // useful for debugging
00065 
00066   virtual nsIAtom* GetChildListName() const { return nsLayoutAtoms::absoluteList; }
00067 
00068   nsresult FirstChild(const nsIFrame* aDelegatingFrame,
00069                       nsIAtom*        aListName,
00070                       nsIFrame**      aFirstChild) const;
00071   
00072   nsresult SetInitialChildList(nsIFrame*       aDelegatingFrame,
00073                                nsPresContext* aPresContext,
00074                                nsIAtom*        aListName,
00075                                nsIFrame*       aChildList);
00076   nsresult AppendFrames(nsIFrame*      aDelegatingFrame,
00077                         nsIAtom*       aListName,
00078                         nsIFrame*      aFrameList);
00079   nsresult InsertFrames(nsIFrame*      aDelegatingFrame,
00080                         nsIAtom*       aListName,
00081                         nsIFrame*      aPrevFrame,
00082                         nsIFrame*      aFrameList);
00083   nsresult RemoveFrame(nsIFrame*      aDelegatingFrame,
00084                        nsIAtom*       aListName,
00085                        nsIFrame*      aOldFrame);
00086   nsresult ReplaceFrame(nsIFrame*      aDelegatingFrame,
00087                         nsIAtom*       aListName,
00088                         nsIFrame*      aOldFrame,
00089                         nsIFrame*      aNewFrame);
00090 
00091   // Called by the delegating frame after it has done its reflow first. This
00092   // function will reflow any absolutely positioned child frames that need to
00093   // be reflowed, e.g., because the absolutely positioned child frame has
00094   // 'auto' for an offset, or a percentage based width or height.
00095   // If aChildBounds is set, it returns (in the local coordinate space) the 
00096   // bounding rect of the absolutely positioned child elements taking into 
00097   // account their overflow area (if it is visible).
00098   // @param aForceReflow if this is false, reflow for some absolutely
00099   //        positioned frames may be skipped based on whether they use
00100   //        placeholders for positioning and on whether the containing block
00101   //        width or height changed.
00102   nsresult Reflow(nsIFrame*                aDelegatingFrame,
00103                   nsPresContext*          aPresContext,
00104                   const nsHTMLReflowState& aReflowState,
00105                   nscoord                  aContainingBlockWidth,
00106                   nscoord                  aContainingBlockHeight,
00107                   nsRect*                  aChildBounds = nsnull,
00108                   PRBool                   aForceReflow = PR_TRUE,
00109                   PRBool                   aCBWidthChanged = PR_TRUE,
00110                   PRBool                   aCBHeightChanged = PR_TRUE);
00111 
00112   // Called by the delegating frame to determine whether the
00113   // incremental reflow is entirely targeted at absolute children
00114   PRBool ReflowingAbsolutesOnly(nsIFrame* aDelegatingFrame,
00115                                 const nsHTMLReflowState& aReflowState);
00116 
00117   // Called only for a reflow reason of eReflowReason_Incremental.
00118   void IncrementalReflow(nsIFrame*                aDelegatingFrame,
00119                          nsPresContext*           aPresContext,
00120                          const nsHTMLReflowState& aReflowState,
00121                          nscoord                  aContainingBlockWidth,
00122                          nscoord                  aContainingBlockHeight);
00123 
00124   void DestroyFrames(nsIFrame*       aDelegatingFrame,
00125                      nsPresContext* aPresContext);
00126 
00127   PRBool  HasAbsoluteFrames() {return mAbsoluteFrames.NotEmpty();}
00128 
00129   void CalculateChildBounds(nsPresContext* aPresContext, nsRect& aChildBounds);
00130 
00131 protected:
00132   // Returns PR_TRUE if the position of f depends on the position of
00133   // its placeholder or if the position or size of f depends on a
00134   // containing block dimension that changed.
00135   PRBool FrameDependsOnContainer(nsIFrame* f, PRBool aCBWidthChanged,
00136                                  PRBool aCBHeightChanged);
00137 
00138   nsresult ReflowAbsoluteFrame(nsIFrame*                aDelegatingFrame,
00139                                nsPresContext*          aPresContext,
00140                                const nsHTMLReflowState& aReflowState,
00141                                nscoord                  aContainingBlockWidth,
00142                                nscoord                  aContainingBlockHeight,
00143                                nsIFrame*                aKidFrame,
00144                                nsReflowReason           aReason,
00145                                nsReflowStatus&          aStatus);
00146 
00147 protected:
00148   nsFrameList mAbsoluteFrames;  // additional named child list
00149 
00150 #ifdef DEBUG
00151   // helper routine for debug printout
00152   void PrettyUC(nscoord aSize,
00153                 char*   aBuf);
00154 #endif
00155 };
00156 
00157 #endif /* nsnsAbsoluteContainingBlock_h___ */
00158