[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
! u9 ~0 J4 s% \4 LHDC hDC; // 绘图句柄
// 打开文件
HANDLE hFile;
if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
8 m  E( J6 J  C# u8 v7 Q9 n) ) != INVALID_HANDLE_VALUE )
{
// 创建文件流
: f/ k3 T" L9 @, r- a( ADWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
9 @0 n- N+ K5 x; KHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
% H6 \5 B3 v/ l, p; _6 ~  iLPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
DWORD dwCount;
% e0 a' `" f( o) m, W( ^( e::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
$ E& a+ Q- _* \- aIStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
9 y% h1 N& \) X# U' Y/ pASSERT( pStream != NULL );
// 从流中装入图片
6 n! Z$ S- Z3 E; pIPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
  D$ Z1 o1 b- y{
8 F& o: v2 Y0 |7 u7 e  {6 ~* @7 _// 向DC中绘图
% Y0 V/ `7 k- }; NOLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
1 k' T% b- e9 p2 Q- BpPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
pPicture->Release();
}
3 `' f  i  V: P" }. B& ~3 V( n% Y// 释放流和文件
. p7 V$ W+ n" @) v; x% C! xpStream->Release();
::CloseHandle( hFile );
}