Streaming IPicture object

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Environment: VC++ 5.0-6.0, NT 4.0,Win2000, Win95/98

I really like the IPicture object. This COM object works very fine. However, I had some problem when I was trying to use it in a Document-View architecture. The main problem is implementation of serialization. To resolve this problem I built two classes.

The first class called CPictureObj. This class is responsible for drawing the picture. The second class, CPictureObjList, is a collection of picture objects. By using both of these classes it is easy to implement the following functionality:

• Load one or more images into document (*.bmp, *.jpeg,
  *.ico,etc…)
  
• Scale images(Zoom In, Zoom Out)
  
• Move images by cursor
  
• Alignment
  
• Save/Load images to/from compound document file.

Classes

class CPictureObj  :

           public CPictureHolder, public CObject

{

  DECLARE_SERIAL(CPictureObj);

public:

  CPictureObj();

  CPictureObj(const CRect position);

  virtual ~CPictureObj();

  void RemoveAndDestroy();

  virtual void Copy( CPictureObj &right);

  virtual HRESULT WriteToStream(IStream* pStream);

  virtual HRESULT ReadFromStream(IStream* pStream);

  

// Attributes

public:

  HorzAlign GetHorzAlign( void ) const;

  void      SetHorzAlign( HorzAlign eHorzAlign );

  VertAlign GetVertAlign( void ) const;

  void      SetVertAlign( VertAlign eVertAlign );

  BOOL      GetSelected( void ) const;

  void      SetSelected( BOOL bValue );

  void      SetVisible(BOOL bValue);

  BOOL      GetVisible();

  CRect     GetPosition();

  void      SetPosition(const CRect pos);

  CRect     GetStartRect();

  void      SetStartRect(const CRect pos);

  CString   GetPathName();

  void      SetPathName(const CString pathname);
  OLE_HANDLE GetHandle();

  CSize      GetSize();          // in himetric

  CSize      GetSize(CDC*pDC);   // in pixel

  CSize      GetSize(CWnd*pWnd); // in pixel

  BOOL       IsValidPicture();



// Operations

public:
  BOOL Load(LPCTSTR szFile);

  BOOL CreateFromFile(const CPoint pt);

  void ReleasePicture();

  void MoveTo(const CRect& position, CWnd* pView);



  // Drawing picture

  void Draw(CDC* pDC);

  void Draw(CDC* pDC, CRect& rcBounds);

  void Draw(CDC* pDC, const CRect&

            rcPosition, const CRect& rcBounds);

  void DrawTracker(CDC* pDC);

  void DrawTracker(CDC* pDC, const CRect& rect);

  void ZoomIn();

  void ZoomOut();
protected:
  void CalcZoom();

  void SetZoomToPosition();
protected:
  HorzAlign m_eHorizAlign;

  VertAlign m_eVertAlign;

  BOOL      m_bSelected;

  BOOL      m_bVisible;

  CRect     m_rcPosition; // in pixels

  CRect     m_startRect;  // in pixels

  int       m_trackerStyle;

  int       m_zoomX,m_zoomY;



  // Not serialized

  CString   m_strPathName;
};
class CPictureObjList : public CTypedPtrList{CObList, CPictureObj*}

{

public:

  ~CPictureObjList();
  void RemoveAndDestroy();

  void DeselectAll();
  CSize ComputeMaxSize();           // in himetric

  CSize ComputeMaxSize(CDC* pDC);   // in pixel

  CSize ComputeMaxSize(CWnd* pWnd); // in pixel

  CRect GetRect();                  // in pixel
  CPictureObj* FindSelected();

  CPictureObj* ObjectAt(const CPoint& pt);

  bool Remove(CPictureObj* pObj);

  void Draw(CDC* pDC);



  // Streaming

  HRESULT WriteToStream(IStream* pStream);

  HRESULT ReadFromStream(IStream* pStream);

  BOOL WriteToStorage(LPSTORAGE lpRootStg);

  BOOL ReadFromStorage(LPSTORAGE lpRootStg);
};

Using the classes.

For use streaming picture create your document object derived from COleDocument.

class CYourDoc : public COleDocument

Define inside of document object the picture collection like here:

CPictureObjList  m_objects;

Now, you can insert picture by simple way:

CPictureObj* pObj =  new CPictureObj;

pObj->CreateFromFile(CPoint(10,10));

m_objects.AddHead(pObj);

Also, you can load picture directly from the file:

CPictureObj* pObj =  new CPictureObj;

pObj->Load("MyFile.jpg");

m_objects.AddHead(pObj);

For scaling picture you can use ZoomIn, ZoomOut member functions:

CPictureObj* pObj = m_objects.FindSelected();

if(pObj)

{

    pObj->ZoomIn();

}

Moving the selected picture is easy:

CPoint delta = point – c_last;

CPictureObj* pSel = m_objects.FindSelected();

if(pSel)

{

  CRect position = pSel->GetPosition();

  position += delta;

  pSel->MoveTo(position, this);

}

Drawing collection of pictures is also easy:

GetDocument()->m_objects.Draw(pDC);

Implementation of picture serialization you can get from here:

void CYourDoc::Serialize(CArchive& ar)

{

 CWaitCursor wait;

 COleDocument::Serialize(ar);

 if (ar.IsStoring())

 {

    m_objects.WriteToStorage(m_lpRootStg);

 }

 else

 {

    m_objects.ReadFromStorage(m_lpRootStg);

    m_objects.DeselectAll();

 }

}

Downloads

Download demo project – 150 Kb
Download source – 6.48 Kb