[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
0 @7 A5 n) }5 r# rHDC hDC; // 绘图句柄
// 打开文件
HANDLE hFile;
) Q5 _8 m0 K- g( N$ V, tif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
8 n1 x( B5 \: F5 i7 P0 P, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
{
// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
- H" ]- t! C+ ?4 ~' j- {9 cASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
) H& I9 w; C  W( Q1 zLPVOID pData = ::GlobalLock( hMemory );
; b& I# L, K2 N3 XASSERT( pData != NULL );
DWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
9 x$ k, u3 Z4 U::GlobalUnlock( hMemory );
IStream * pStream = NULL;
* \9 R2 ^* I5 `, y" z, g/ ~0 c::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
5 h5 y. r& C/ g5 l6 _1 Z2 S1 d* Z// 从流中装入图片
0 w9 d" v# W* s% t$ RIPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
( l7 N  O+ X$ JID* )&pPicture ) ) )
% G" |7 r5 w. I+ E8 m{
, w! O8 X9 L( x# F- t// 向DC中绘图
" w1 C' Y# J% D$ f' ?OLE_XSIZE_HIMETRIC hmWidth;
! ?- [: h, F+ K6 R3 z$ p( L/ e- ROLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
4 p. s* T. l' Y8 LpPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
4 V8 L$ P9 T' Z  H& epPicture->Release();
}
// 释放流和文件
pStream->Release();
::CloseHandle( hFile );
1 {  A, Z: X5 C8 {) b' z6 l3 b}