[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
// 打开文件
HANDLE hFile;
/ n+ @' ^1 B( N8 l6 J9 Iif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
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// 创建文件流
8 ~, m) O* J  g  v5 G8 H" h2 vDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
2 c# i8 N* L: D4 L5 e. vASSERT( dwSize != -1 );
+ y0 c5 q* }* }9 H; t, a( LHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
/ f( ~" o5 {+ W$ Y/ d* p8 W2 t' cASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
8 K  V: u- a" H& uASSERT( pData != NULL );
DWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
- H, p1 n. X8 \+ e::GlobalUnlock( hMemory );
IStream * pStream = NULL;
- Q0 Z' z- @/ C' l9 j7 H::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
// 从流中装入图片
8 X5 d% \- X3 ?8 [2 Z+ k9 oIPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
$ A& Y7 t9 t; Y: A' @ID* )&pPicture ) ) )
1 e- w. a3 c/ I8 }$ P9 Z# Q{
// 向DC中绘图
6 g0 n3 C! D2 |! f) S' s# T" }4 gOLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
0 k7 H- B- ?+ FpPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
, w9 x$ F3 z2 N; t* Z2 K3 _LL );
pPicture->Release();
8 \6 F! Q$ ~- e" }" L2 E$ n! X}
// 释放流和文件
pStream->Release();
::CloseHandle( hFile );
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