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->SaveAsFil
e(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
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;getsavefilename
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();
pNe
wPic = NULL;
DeleteObject(hBmp);
hBmp = NULL;
return TRUE;
}
DeleteObject(hBmp);
hBmp = NULL;
return FALSE;
}

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