[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
( ^* b6 P6 R  Y- HHDC hDC; // 绘图句柄
// 打开文件
4 }& K+ [2 i8 ]/ j3 OHANDLE hFile;
if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
: c& Z( s5 z* D7 L{
$ M' K& O6 v% z& w) A# |// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
; c; M: O) Q) E( k& SASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
( w. R! m: z. R! dASSERT( pData != NULL );
" I$ B5 V8 j0 `( W/ b- ADWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
, H  A# k1 h! h: X0 R1 LIStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
; y( n( F8 T% H' m, G3 ]" R$ H// 从流中装入图片
' Y' j4 M2 F  f0 N( {/ cIPicture * pPicture = NULL;
: q' z* M: u0 m+ pif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
: \3 s% v, z! Y8 B{
// 向DC中绘图
2 ?4 L* q' y2 XOLE_XSIZE_HIMETRIC hmWidth;
9 x, i3 r% z6 f( Q: KOLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
4 c; U$ \% k9 U2 O5 bpPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
; y7 U3 ~' q, a  Z1 q) HLL );
pPicture->Release();
}
/ a& v, C4 \7 [. ?; N// 释放流和文件
pStream->Release();
* Q( q" p; l! i::CloseHandle( hFile );
5 L/ ]( V! i) [6 z; `}