IPicture使用总结

1、IPicture接口对象的创建
         方法1：直接通过文件创建
LPCSTR szFileUrl;
 IPicture *pIPicture;
 OleLoadPicturePath(CComBSTR(szFileUrl), 
   (LPUNKNOWN)NULL, 
   0, 
   0, 
   IID_IPicture,
   (LPVOID*)&pIPicture))
        方法2：通过IStream来创建
 // 加载电子地图
 LPCSTR szFileUrl;
 IStream *pStream = NULL;
 IPicture *pIPicture = NULL;;
 CFileStatus fstatus;
 CFile file;
 LONG lFileSize;
 HGLOBAL hGlobal;
 if(file.Open(szFileUrl, CFile::modeRead) && file.GetStatus(szFileUrl, fstatus) 
  && ((lFileSize = fstatus.m_size) != -1))
 {
  hGlobal = GlobalAlloc(GMEM_MOVEABLE, lFileSize);// 开辟大内存
  if(hGlobal != NULL)
  {
   LPVOID pvData = NULL;
   pvData = GlobalLock(hGlobal);
   if(pvData != NULL)
   { 
    file.ReadHuge(pvData, lFileSize);   // 将图片数据保存在内存中
    GlobalUnlock(hGlobal);
    CreateStreamOnHGlobal(hGlobal, TRUE, &m_pIStream);  // 创建流
    file.Close();
   }
   else
   {
    GlobalFree(hGlobal);
    return;
   }
  }
  else
  {
   file.Close();
   return;
  }
 }
 else
 {
  //打开图片失败
  return;
 }
 OleLoadPicture(m_pIStream, fstatus.m_size, TRUE, IID_IPicture, (LPVOID*)&m_pIPicture);
 GlobalFree(hGlobal);

2、通过IPicture来获取图片的尺寸
 OLE_XSIZE_HIMETRIC hmPicWidth;       
 OLE_YSIZE_HIMETRIC hmPicHeight;      
 pIPicture->get_Width(&hmPicWidth);   // 获取图像宽度
 pIPicture->get_Height(&hmPicHeight); // 获取图像高度
 // 转化单位为象素
 nPicWidth = MulDiv(hmPicWidth, GetDeviceCaps(GetDC()->m_hDC, LOGPIXELSX), HIMETRIC_PER_INCH);
 nPicHeight = MulDiv(hmPicHeight, GetDeviceCaps(GetDC()->m_hDC, LOGPIXELSY), HIMETRIC_PER_INCH);

3、通过IPicture来画图
void ShowPicture(CDC *pDC)
{
 OLE_XPOS_HIMETRIC xSrc;  // 图片中当前显示区域的x
 OLE_YPOS_HIMETRIC ySrc;  // 图片中当前显示区域的y
 OLE_XSIZE_HIMETRIC cxSrc; // 图片中当前显示区域的宽度
 OLE_YSIZE_HIMETRIC cySrc; // 图片中当前显示区域的高度
 m_pIPicture->Render(*pDC, 0, 0, m_rcBox.Width(), m_rcBox.Height(), xSrc, ySrc, cxSrc, cySrc, NULL);
}

4、将IPicture中的图片保存起来
BOOL SaveToFileFromIPicture(LPCSTR szFileName, IPicture *pPic)
{
 // Create ILockBytes Buffer
 ILockBytes *plkbyt = NULL;
 CreateILockBytesOnHGlobal(NULL, TRUE, &plkbyt);

 // Create IStorage
 IStorage   *pStorage = NULL;
 HRESULT hr = ::StgCreateDocfileOnILockBytes(plkbyt,
  STGM_SHARE_EXCLUSIVE | STGM_CREATE | STGM_READWRITE, 0, &pStorage);
 if (FAILED(hr))
 {
  plkbyt->Release();
  plkbyt = NULL;
  return FALSE;
 }

 // Create IStream
 IStream    *pStream = NULL;
 hr = pStorage->CreateStream(L"PICTURE",
  STGM_SHARE_EXCLUSIVE | STGM_CREATE | STGM_READWRITE, 0, 0, &pStream);
 if (FAILED(hr))
 {
  pStorage->Release();
  pStorage = NULL;
  plkbyt->Release();
  plkbyt = NULL;
  return FALSE;
 }
 
 // Copy Data Stream
 long  lSize;
 hr = pPic->SaveAsFile(pStream, TRUE, &lSize); 
 if (FAILED(hr))
 {
  pStream->Release();
  pStream = NULL;
  pStorage->Release();
  pStorage = NULL;
  plkbyt->Release();
  plkbyt = NULL;
  return FALSE;
 }
 // Get Statistics For Final Size Of Byte Array
 STATSTG  statStg;
 hr = plkbyt->Stat(&statStg, STATFLAG_NONAME);
 if (FAILED(hr))
 {
  pStream->Release();
  pStream = NULL;
  pStorage->Release();
  pStorage = NULL;
  plkbyt->Release();
  plkbyt = NULL;
  return FALSE;
 }

 // calculate "Pure" Picture Data, Must Be In a 512 Blocks...
 double  dbSkipFloat = (double(lSize) / 512);   
 DWORD  dwPicDataSize = 0;
 if(dbSkipFloat > DWORD(dbSkipFloat)) 
 {
  dwPicDataSize = (DWORD)dbSkipFloat + 1;
 }
 else 
 {
  dwPicDataSize = (DWORD)dbSkipFloat;
 }
 dwPicDataSize = dwPicDataSize * 512; 
 // Allocate Only The "Pure" Picture Data
 BYTE  *pPicDataBuffer = (BYTE*)malloc(dwPicDataSize);
 if (pPicDataBuffer == NULL)
 {
  pStream->Release();
  pStream = NULL;
  plkbyt->Release();
  pStorage->Release();
  pStorage = NULL;
  plkbyt = NULL;
  return FALSE;
 }
 
 // Read "Pure" Picture Data to Buffer
 _ULARGE_INTEGER ulOffset;
 ulOffset.LowPart = 0;
 ulOffset.HighPart = 0;
 ulOffset.QuadPart = (DWORD)(statStg.cbSize.QuadPart - dwPicDataSize);
 DWORD dwRealDataSize;
 hr = plkbyt->ReadAt(ulOffset, pPicDataBuffer, dwPicDataSize, &dwRealDataSize);
 if (FAILED(hr))
 {
  free(pPicDataBuffer);
  pPicDataBuffer = NULL;
  pStream->Release();
  pStream = NULL;
  pStorage->Release();
  pStorage = NULL;
  plkbyt->Release();
  plkbyt = NULL;
  return FALSE;
 }
 
 // Save "Pure" Picture Data to file
 CFile  fBmp; 
 CFileException e;
 if (!fBmp.Open(szFileName, CFile::typeBinary | CFile::modeCreate | CFile::modeWrite, &e))
 {
  free(pPicDataBuffer);
  pPicDataBuffer = NULL;
  pStream->Release();
  pStream = NULL;
  pStorage->Release();
  pStorage = NULL;
  plkbyt->Release();
  plkbyt = NULL;
  return FALSE;
 }
 fBmp.Write(pPicDataBuffer, dwRealDataSize);
 fBmp.Close();
 free(pPicDataBuffer);
 pPicDataBuffer = NULL;
 pStream->Release();
 pStream = NULL;
 pStorage->Release();
 pStorage = NULL;
 plkbyt->Release();
 plkbyt = NULL;
 return TRUE;
}

5、将IPicture中图片按规定的尺寸保存
BOOL CIPictureDlg::Save2File(LPCSTR szFileName, IPicture *pPic, int nWidth, int nHeight)
{
 // create a new IPicture
 OLE_HANDLE hPic = NULL;
 if (FAILED(pPic->get_Handle(&hPic)))
 {
  return FALSE;
 }
 HBITMAP hBmp = (HBITMAP)CopyImage((HANDLE)hPic,
   IMAGE_BITMAP, 
   nWidth, 
   nWidth, 
   LR_CREATEDIBSECTION);
 if (hBmp == NULL)
 {
  return FALSE;
 }
 PICTDESC picDesc;
 picDesc.cbSizeofstruct = sizeof(PICTDESC);
 picDesc.picType = PICTYPE_BITMAP;
 picDesc.bmp.hbitmap = hBmp;

 IPicture *pNewPic = NULL;
 if (SUCCEEDED(OleCreatePictureIndirect(&picDesc, IID_IPicture, FALSE, (LPVOID *)&pNewPic)))
 {
  // Save to file
  Save2File(szFileName, pNewPic);
  pNewPic->Release();
  pNewPic = NULL;
  DeleteObject(hBmp);
  hBmp = NULL;
  return TRUE;
 }
 DeleteObject(hBmp);
 hBmp = NULL;
 return FALSE;
}