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/* rendering object that goes directly inside the document's scrollbars */

#ifndef nsCanvasFrame_h___
#define nsCanvasFrame_h___


#include "nsHTMLContainerFrame.h"
#include "nsStyleContext.h"
#include "nsIRenderingContext.h"
#include "nsGUIEvent.h"
#include "nsGkAtoms.h"
#include "nsIScrollPositionListener.h"
#include "nsDisplayList.h"
#include "nsAbsoluteContainingBlock.h"

class nsPresContext;

/**
 * Root frame class.
 *
 * The root frame is the parent frame for the document element's frame.
 * It only supports having a single child frame which must be an area
 * frame
 */
class nsCanvasFrame : public nsHTMLContainerFrame, 
                      public nsIScrollPositionListener
{
public:
  nsCanvasFrame(nsStyleContext* aContext)
  : nsHTMLContainerFrame(aContext), mDoPaintFocus(PR_FALSE),
    mAbsoluteContainer(nsGkAtoms::absoluteList) {}

  NS_DECL_QUERYFRAME_TARGET(nsCanvasFrame)
  NS_DECL_QUERYFRAME
  NS_DECL_FRAMEARENA_HELPERS


  virtual void DestroyFrom(nsIFrame* aDestructRoot);

  NS_IMETHOD SetInitialChildList(nsIAtom*        aListName,
                                 nsFrameList&    aChildList);
  NS_IMETHOD AppendFrames(nsIAtom*        aListName,
                          nsFrameList&    aFrameList);
  NS_IMETHOD InsertFrames(nsIAtom*        aListName,
                          nsIFrame*       aPrevFrame,
                          nsFrameList&    aFrameList);
  NS_IMETHOD RemoveFrame(nsIAtom*        aListName,
                         nsIFrame*       aOldFrame);

  virtual nsIAtom* GetAdditionalChildListName(PRInt32 aIndex) const;
  virtual nsFrameList GetChildList(nsIAtom* aListName) const;

  virtual nscoord GetMinWidth(nsIRenderingContext *aRenderingContext);
  virtual nscoord GetPrefWidth(nsIRenderingContext *aRenderingContext);
  NS_IMETHOD Reflow(nsPresContext*          aPresContext,
                    nsHTMLReflowMetrics&     aDesiredSize,
                    const nsHTMLReflowState& aReflowState,
                    nsReflowStatus&          aStatus);
  virtual PRBool IsContainingBlock() const { return PR_TRUE; }
  virtual PRBool IsFrameOfType(PRUint32 aFlags) const
  {
    return nsHTMLContainerFrame::IsFrameOfType(aFlags &
             ~(nsIFrame::eCanContainOverflowContainers));
  }

  /** SetHasFocus tells the CanvasFrame to draw with focus ring
   *  @param aHasFocus PR_TRUE to show focus ring, PR_FALSE to hide it
   */
  NS_IMETHOD SetHasFocus(PRBool aHasFocus);

  NS_IMETHOD BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                              const nsRect&           aDirtyRect,
                              const nsDisplayListSet& aLists);

  void PaintFocus(nsIRenderingContext& aRenderingContext, nsPoint aPt);

  // nsIScrollPositionListener
  virtual void ScrollPositionWillChange(nscoord aX, nscoord aY);
  virtual void ScrollPositionDidChange(nscoord aX, nscoord aY) {}

  /**
   * Get the "type" of the frame
   *
   * @see nsGkAtoms::canvasFrame
   */
  virtual nsIAtom* GetType() const;

  virtual nsresult StealFrame(nsPresContext* aPresContext,
                              nsIFrame*      aChild,
                              PRBool         aForceNormal)
  {
    NS_ASSERTION(!aForceNormal, "No-one should be passing this in here");

    // nsCanvasFrame keeps overflow container continuations of its child
    // frame in main child list
    nsresult rv = nsContainerFrame::StealFrame(aPresContext, aChild, PR_TRUE);
    if (NS_FAILED(rv)) {
      rv = nsContainerFrame::StealFrame(aPresContext, aChild);
    }
    return rv;
  }

#ifdef DEBUG
  NS_IMETHOD GetFrameName(nsAString& aResult) const;
#endif
  NS_IMETHOD GetContentForEvent(nsPresContext* aPresContext,
                                nsEvent* aEvent,
                                nsIContent** aContent);

  nsRect CanvasArea() const;

protected:
  virtual PRIntn GetSkipSides() const;

  // Data members
  PRPackedBool              mDoPaintFocus;
  PRPackedBool              mAddedScrollPositionListener;
  nsAbsoluteContainingBlock mAbsoluteContainer;
};

#endif /* nsCanvasFrame_h___ */
