[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
" |) R# t5 ~/ w9 S* f& q2 EHDC 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
! I5 C9 q+ o' |  D3 v& A! E) ) != INVALID_HANDLE_VALUE )
2 j3 m  u. ~2 N" L8 }/ K{
// 创建文件流
5 W: L2 o. D/ k+ q& d6 {DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
( c- O1 r' s/ L1 OASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
DWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
& s$ w3 j% \  T8 A6 t; D2 j9 i::GlobalUnlock( hMemory );
8 y: L! V1 Q3 S+ ?4 |1 T* h$ Z$ sIStream * pStream = NULL;
: c8 Y( h1 `8 Z9 r::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
// 从流中装入图片
IPicture * pPicture = NULL;
" _' Z& Z6 D7 s/ Fif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
$ o0 u" W9 S$ EID* )&pPicture ) ) )
* L1 N; N. F7 C7 M- b; r$ h, I{
) U' B1 c7 R8 E0 m5 j1 V// 向DC中绘图
# ]1 Z& m* J; SOLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
  j0 P# v  Q6 e' VpPicture->get_Height( &hmHeight );
4 p% H3 }- R3 @, F7 apPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
pPicture->Release();
}
- q' {0 S# d2 u+ @// 释放流和文件
5 z+ G" D% Y/ r# f; QpStream->Release();
::CloseHandle( hFile );
}