gecko-dev/layout/generic/nsImageFrame.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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#ifndef nsImageFrame_h___
#define nsImageFrame_h___

#include "nsSplittableFrame.h"
#include "nsString.h"
#include "nsAString.h"
#include "nsIPresContext.h"
#include "nsIImageFrame.h"

#include "nsTransform2D.h"
#include "imgIRequest.h"
#include "imgIDecoderObserver.h"
#include "imgIContainerObserver.h"

class nsIFrame;
class nsImageMap;
class nsIURI;
class nsILoadGroup;
struct nsHTMLReflowState;
struct nsHTMLReflowMetrics;
struct nsSize;

class nsImageFrame;

class nsImageListener : public imgIDecoderObserver
{
public:
  nsImageListener(nsImageFrame *aFrame);
  virtual ~nsImageListener();

  NS_DECL_ISUPPORTS
  NS_DECL_IMGIDECODEROBSERVER
  NS_DECL_IMGICONTAINEROBSERVER

  void SetFrame(nsImageFrame *frame) { mFrame = frame; }

private:
  nsImageFrame *mFrame;
};

#define IMAGE_SIZECONSTRAINED       0x00100000
#define IMAGE_GOTINITIALREFLOW      0x00200000

#define ImageFrameSuper nsSplittableFrame

class nsImageFrame : public ImageFrameSuper, public nsIImageFrame {
public:
  nsImageFrame();

  // nsISupports 
  NS_IMETHOD QueryInterface(const nsIID& aIID, void** aInstancePtr);

  NS_IMETHOD Destroy(nsIPresContext* aPresContext);
  NS_IMETHOD Init(nsIPresContext*  aPresContext,
                  nsIContent*      aContent,
                  nsIFrame*        aParent,
                  nsStyleContext*  aContext,
                  nsIFrame*        aPrevInFlow);
  NS_IMETHOD Paint(nsIPresContext*      aPresContext,
                   nsIRenderingContext& aRenderingContext,
                   const nsRect&        aDirtyRect,
                   nsFramePaintLayer    aWhichLayer,
                   PRUint32             aFlags = 0);
  NS_IMETHOD Reflow(nsIPresContext*          aPresContext,
                    nsHTMLReflowMetrics&     aDesiredSize,
                    const nsHTMLReflowState& aReflowState,
                    nsReflowStatus&          aStatus);
  
  NS_IMETHOD  ContentChanged(nsIPresContext* aPresContext,
                             nsIContent*     aChild,
                             nsISupports*    aSubContent);

  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const;


  NS_IMETHOD  GetContentForEvent(nsIPresContext* aPresContext,
                                 nsEvent* aEvent,
                                 nsIContent** aContent);
  NS_IMETHOD HandleEvent(nsIPresContext* aPresContext,
                        nsGUIEvent* aEvent,
                        nsEventStatus* aEventStatus);
  NS_IMETHOD GetCursor(nsIPresContext* aPresContext,
                       nsPoint& aPoint,
                       PRInt32& aCursor);
  NS_IMETHOD AttributeChanged(nsIPresContext* aPresContext,
                              nsIContent* aChild,
                              PRInt32 aNameSpaceID,
                              nsIAtom* aAttribute,
                              PRInt32 aModType);

#ifdef ACCESSIBILITY
  NS_IMETHOD GetAccessible(nsIAccessible** aAccessible);
#endif

  virtual nsIAtom* GetType() const;
#ifdef DEBUG
  NS_IMETHOD List(nsIPresContext* aPresContext, FILE* out, PRInt32 aIndent) const;
#endif

  NS_IMETHOD GetImageMap(nsIPresContext *aPresContext, nsIImageMap **aImageMap);

  NS_IMETHOD GetIntrinsicImageSize(nsSize& aSize);

protected:
  // nsISupports
  NS_IMETHOD_(nsrefcnt) AddRef(void);
  NS_IMETHOD_(nsrefcnt) Release(void);

  virtual ~nsImageFrame();

  virtual void GetDesiredSize(nsIPresContext* aPresContext,
                              const nsHTMLReflowState& aReflowState,
                              nsHTMLReflowMetrics& aDesiredSize);

  nsImageMap* GetImageMap(nsIPresContext* aPresContext);

  void TriggerLink(nsIPresContext* aPresContext,
                   nsIURI* aURI,
                   const nsString& aTargetSpec,
                   PRBool aClick);

  PRBool IsServerImageMap();

  void TranslateEventCoords(nsIPresContext* aPresContext,
                            const nsPoint& aPoint,
                            nsPoint& aResult);

  PRBool GetAnchorHREFAndTarget(nsString& aHref, nsString& aTarget);

  void MeasureString(const PRUnichar*     aString,
                     PRInt32              aLength,
                     nscoord              aMaxWidth,
                     PRUint32&            aMaxFit,
                     nsIRenderingContext& aContext);

  void DisplayAltText(nsIPresContext*      aPresContext,
                      nsIRenderingContext& aRenderingContext,
                      const nsString&      aAltText,
                      const nsRect&        aRect);

  void DisplayAltFeedback(nsIPresContext*      aPresContext,
                          nsIRenderingContext& aRenderingContext,
                          PRInt32              aIconId);

  void GetInnerArea(nsIPresContext* aPresContext,
                    nsRect& aInnerArea) const;

protected:
  friend class nsImageListener;
  nsresult OnStartContainer(imgIRequest *aRequest, imgIContainer *aImage);
  nsresult OnDataAvailable(imgIRequest *aRequest,
                           gfxIImageFrame *aFrame,
                           const nsRect * rect);
  nsresult OnStopDecode(imgIRequest *aRequest,
                        nsresult aStatus,
                        const PRUnichar *aStatusArg);
  nsresult FrameChanged(imgIContainer *aContainer,
                        gfxIImageFrame *aNewframe,
                        nsRect *aDirtyRect);

private:
  // random helpers
  inline void SpecToURI(const nsAString& aSpec, nsIIOService *aIOService,
                        nsIURI **aURI);

  inline void GetLoadGroup(nsIPresContext *aPresContext,
                           nsILoadGroup **aLoadGroup);
  nscoord GetContinuationOffset(nscoord* aWidth = 0) const;
  void GetDocumentCharacterSet(nsACString& aCharset) const;

  /**
   * This function will recalculate mTransform.  If a non-null image
   * is passed in, mIntrinsicSize will be recalculated from the image
   * size.  Otherwise, mIntrinsicSize will not be touched.
   *
   * @return PR_TRUE if aImage is non-null and its size did _not_
   *         match our previous intrinsic size
   * @return PR_FALSE otherwise
   */
  PRBool RecalculateTransform(imgIContainer* aImage);

  /**
   * Helper functions to check whether the request or image container
   * corresponds to a load we don't care about.  Most of the decoder
   * observer methods will bail early if these return true.
   */
  PRBool IsPendingLoad(imgIRequest* aRequest) const;
  PRBool IsPendingLoad(imgIContainer* aContainer) const;

  /**
   * Helper to convert a rect in pixels to one in twips using the
   * prescontext's p2t factor
   */
  nsRect ConvertPxRectToTwips(const nsRect & aRect) const;

  /**
   * Function to call when a load fails; this handles things like alt
   * text, broken image icons, etc.  Returns NS_ERROR_FRAME_REPLACED
   * if it called CantRenderReplacedElement, NS_OK otherwise.
   */
  nsresult HandleLoadError(nsresult aStatus, nsIPresShell* aPresShell);
  
  nsImageMap*         mImageMap;

  nsCOMPtr<imgIDecoderObserver> mListener;

  nsSize mComputedSize;
  nsSize mIntrinsicSize;
  nsTransform2D mTransform;
  
  nsMargin            mBorderPadding;

  nsIPresContext*     mPresContext;  // weak ref

  /* loading / broken image icon support */

  // XXXbz this should be handled by the prescontext, I think; that
  // way we would have a single iconload per mozilla session instead
  // of one per document...

  // LoadIcons: initiate the loading of the static icons used to show
  // loading / broken images
  nsresult LoadIcons(nsIPresContext *aPresContext);
  nsresult LoadIcon(const nsAString& aSpec, nsIPresContext *aPresContext,
                    imgIRequest **aRequest);
  
  // HandleIconLoads: See if the request is for an Icon load. If it
  // is, handle it and return TRUE otherwise, return FALSE (aCompleted
  // is an input arg telling the routine if the request has completed)
  PRBool HandleIconLoads(imgIRequest* aRequest, PRBool aCompleted);
  void InvalidateIcon(nsIPresContext *aPresContext);

  class IconLoad;
  friend class IconLoad; // to allow |IconLoad| to access |SingleIconLoad|.
  struct SingleIconLoad {
    nsCOMPtr<imgIRequest> mRequest;
  };

  class IconLoad {
    // private class that wraps the data and logic needed for 
    // broken image and loading image icons
  public:
    IconLoad(nsIPresContext *aPresContext, imgIDecoderObserver* aObserver)
      : mRefCount(0),
        mLoadObserver(aObserver),
        mIconsLoaded(PR_FALSE)
    {
      GetPrefs(aPresContext);
    }

    ~IconLoad()
    {
      if (mIconLoads[0].mRequest) {
        mIconLoads[0].mRequest->Cancel(NS_ERROR_FAILURE);
      }
      if (mIconLoads[1].mRequest) {
        mIconLoads[1].mRequest->Cancel(NS_ERROR_FAILURE);
      }
    }

    void AddRef(void) { ++mRefCount; }
    PRBool Release(void) { return --mRefCount == 0; }
  private:
    void GetPrefs(nsIPresContext *aPresContext);

    PRUint32         mRefCount;

    // values for image loading icons
#define NS_ICON_LOADING_IMAGE (0)
#define NS_ICON_BROKEN_IMAGE  (1)
  public:
    struct SingleIconLoad mIconLoads[2];
    nsCOMPtr<imgIDecoderObserver> mLoadObserver; // keeps the observer alive
    PRPackedBool     mIconsLoaded;
    PRPackedBool     mPrefForceInlineAltText;
    PRPackedBool     mPrefAllImagesBlocked;
    PRPackedBool     mPrefShowPlaceholders;
  };
  static IconLoad* mIconLoad; // singleton pattern: one LoadIcons instance is used
};

#endif /* nsImageFrame_h___ */