[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
HDC hDC; // 绘图句柄
9 M: ~* e. _! j' S// 打开文件
5 Y- v8 R' {4 s) ?9 a) Z  A" C) M. _HANDLE hFile;
7 n$ w: f( W: z! \if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
3 ^1 T8 Y$ q9 |: w) ) != INVALID_HANDLE_VALUE )
{
// 创建文件流
% q" |- q; g: X; ?/ d, \DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
/ c. _6 y; L2 g0 N: V. S' ?ASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
' O0 f! X' e! P; C/ \8 hASSERT( pData != NULL );
DWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
4 L9 X, X( ?5 l- z  ^% F& k- ]- M::GlobalUnlock( hMemory );
IStream * pStream = NULL;
$ ?1 R0 h5 k( w! B- ?::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
5 C# H' ~1 I2 [1 |// 从流中装入图片
+ o, f+ V. k! @6 S, ?3 MIPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
1 z3 `: k5 e0 y6 JID* )&pPicture ) ) )
. L7 m6 d% @. ^+ G: R& }{
// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
8 B* z* e9 b- `0 @. g; ^3 ?" w* k- S9 UpPicture->get_Width( &hmWidth );
5 \: e$ r" [* @7 O3 `+ v* ], vpPicture->get_Height( &hmHeight );
+ y9 B+ N; \) U5 c1 M% OpPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
3 ~) K7 Y6 L+ W( @2 s2 Q  p7 NpPicture->Release();
1 a+ q/ j, h+ M+ \" I) R}
+ x. {8 Y% Y# g. N// 释放流和文件
4 U% ~5 E6 \& B0 TpStream->Release();
2 ^5 P' n0 A" ]# O::CloseHandle( hFile );
}