[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;
if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
3 @0 Z& B6 ^2 A8 m" P, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
6 t6 A' [8 e; ?1 t: K/ \1 c{
// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
" n- L* F; Q/ w, _: V- zASSERT( dwSize != -1 );
% [9 l/ s, x7 ~5 V8 RHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
DWORD dwCount;
4 B4 }! A, y% A" F::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
4 o$ _, ^3 G, |7 y( ]% o::GlobalUnlock( hMemory );
3 x. }# d; y0 g$ p& a% O! _1 AIStream * pStream = NULL;
7 {/ a$ r' x( k8 C3 D::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
' ]7 Y% g4 g& _// 从流中装入图片
, _  ^- D7 [1 d4 n: ~. [; @% ^IPicture * pPicture = NULL;
3 T6 g# M) f9 D" p6 uif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
" j# p* L# C2 A  x, j1 K( T" TID* )&pPicture ) ) )
{
+ w8 ?$ \( {. d# c// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
pPicture->Release();
}
// 释放流和文件
; e; V( Z1 F, _# M+ }  J4 Y4 C% {pStream->Release();
" ?4 `; K( E7 h: ^. @5 y) `# j9 N::CloseHandle( hFile );
% Q" x9 T. f# O}