[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
/ ^$ W, t1 ~; C5 f" r+ g// 打开文件
HANDLE hFile;
8 j4 [: }3 u# O0 H. S& R: l% Gif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
( c4 }9 O/ t. O& M" ?& i, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
0 Y6 \' g% N! N" E6 i# M8 W  X) ) != INVALID_HANDLE_VALUE )
6 m# |2 Q. |$ U# E0 p! j{
# ?2 _4 s9 Y* N5 C0 E; u// 创建文件流
2 m  ?0 y; A3 C  uDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
: a' ^# }' B" Y2 f2 j4 ]) J9 vASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
+ c3 }3 D2 `! \  \% H# i! WASSERT( hMemory != NULL );
( o; L1 s3 M) G1 [LPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
DWORD dwCount;
( I3 R% P3 S6 ~1 r6 `- F+ \::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
+ c0 g$ r+ o# i* `5 CIStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
' p8 ^) X6 I$ G- ^// 从流中装入图片
IPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
0 R6 I! R& x0 H1 {4 }. CID* )&pPicture ) ) )
6 r4 @: a+ C) W1 K; p. H9 x{
// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
. {( i6 f! M" x: ?9 oOLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
$ c9 N2 o( _# K. r1 m1 }* n! HpPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
pPicture->Release();
3 b' `/ q6 u9 B+ c! V3 l9 |; \}
// 释放流和文件
/ m: O& ^4 ^1 L4 Y3 f* BpStream->Release();
::CloseHandle( hFile );
+ R% g/ k' ?% v9 @1 |}