загружаем
| Код |
bool LoadPictFromFile(IPicture** gpPicture, const char *szFile)
{
bool pict_loaded;
if (gpPicture)
gpPicture->Release();
*gpPicture=0;
pict_loaded=false;
// open file
HANDLE hFile = ::CreateFile(szFile, GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL);
if (INVALID_HANDLE_VALUE == hFile)
return false;
// get file size
DWORD dwFileSize = ::GetFileSize(hFile, NULL);
if ( -1 == dwFileSize )
{
CloseHandle(hFile);
return false;
}
LPVOID pvData = NULL;
// alloc memory based on file size
HGLOBAL hGlobal = ::GlobalAlloc(GMEM_MOVEABLE, dwFileSize);
if (NULL == hGlobal)
{
_ASSERTE(NULL != hGlobal);
::CloseHandle(hFile);
return false;
}
pvData = GlobalLock(hGlobal);
if (NULL == pvData)
{
_ASSERTE(NULL != pvData);
::GlobalFree(hGlobal);
::CloseHandle(hFile);
return false;
}
DWORD dwBytesRead = 0;
// read file and store in global memory
BOOL bRead = ::ReadFile(hFile, pvData, dwFileSize, &dwBytesRead, NULL);
::CloseHandle(hFile);
if (FALSE == bRead || dwFileSize!=dwBytesRead)
{
::GlobalUnlock(hGlobal);
::GlobalFree(hGlobal);
return false;
}
LPSTREAM pstm = NULL;
// create IStream* from global memory
HRESULT hr = ::CreateStreamOnHGlobal(hGlobal, TRUE, &pstm);
if (!SUCCEEDED(hr) || !pstm)
{
::GlobalUnlock(hGlobal);
::GlobalFree(hGlobal);
return false;
}
// Create IPicture from image file
hr = ::OleLoadPicture(pstm, dwFileSize, FALSE, IID_IPicture, (LPVOID*) gpPicture);
pstm->Release();
if (!SUCCEEDED(hr) || !gpPicture)
{
*gpPicture=0;
pict_loaded=false;
}
else
pict_loaded=true;
::GlobalUnlock(hGlobal);
::GlobalFree(hGlobal);
return pict_loaded;
}
|
Теперь, когда в объекте IPicture у нас есть загруженное изображение, то можно его вывести на экран
| Код |
#define HIMETRIC_INCH 2540
#define MAP_LOGHIM_TO_PIX(x,ppli) ( ((ppli)*(x) + HIMETRIC_INCH/2) / HIMETRIC_INCH )
IPicture* gpPicture;
.....
LoadPictFromFile(...........);
.....
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
if (gpPicture)
{
// get width and height of picture
long hmWidth;
long hmHeight;
gpPicture->get_Width(&hmWidth);
gpPicture->get_Height(&hmHeight);
// convert himetric to pixels
int nWidth = MulDiv(hmWidth, GetDeviceCaps(hdc, LOGPIXELSX), HIMETRIC_INCH);
int nHeight = MulDiv(hmHeight, GetDeviceCaps(hdc, LOGPIXELSY), HIMETRIC_INCH);
RECT rc;
GetClientRect(hWnd, &rc);
// display picture using IPicture::Render
gpPicture->Render(hdc, 0, 0, nWidth, nHeight, 0, hmHeight, hmWidth, -hmHeight, &rc);
};
EndPaint(hWnd, &ps);
break;
}
|
Естественно, точно также можно "отрендерить" картинку в свой DC с выбранным в нем HBITMAP |
