Question

在vc中怎样读取jpg文件

Answer 1

PICDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);

IPicture *pPic;
IStream *pStm;

CFileStatus fstatus;
CFile file;
LONG cb;

if (file.Open("c:/test.jpg",CFile::modeRead)&&file.GetStatus("c:/test.jpg",
fstatus)&&
((cb = fstatus.m_size) != -1))
{
HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, cb);
LPVOID pvData = NULL;
if (hGlobal != NULL)
{
if ((pvData = GlobalLock(hGlobal)) != NULL)
{
file.ReadHuge(pvData, cb);
GlobalUnlock(hGlobal);
CreateStreamOnHGlobal(hGlobal, TRUE, &pStm);

if(SUCCEEDED(OleLoadPicture(pStm,fstatus.m_size,TRUE,IID_IPicture,(LPVOID*
)&pPic)))
{
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;

pPic->get_Width(&hmWidth);
pPic->get_Height(&hmHeight);

double fX,fY;
fX = (double)pDC->GetDeviceCaps(HORZRES)*(double)hmWidth/((double)pDC->Ge
tDeviceCaps(HORZSIZE)*100.0);
fY = (double)pDC->GetDeviceCaps(VERTRES)*(double)hmHeight/((double)pDC->G
etDeviceCaps(VERTSIZE)*100.0);
if(FAILED(pPic->Render(*pDC,0,0,(DWORD)fX,(DWORD)fY,0,hmHeight,hmWidth,-h
mHeight,NULL)))
AfxMessageBox("Failed To Render The picture!");
pPic->Release();
}
else
AfxMessageBox("Error Loading Picture From Stream!");
}
}
}
else
AfxMessageBox("Can't Open Image File!");

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