[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
; e# Y8 l( ?) s4 e// 打开文件
# j' g2 Z' J, t- L, f/ @5 z) vHANDLE hFile;
: Q+ z  b0 P! h* b, b9 D+ M4 wif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
: b; S* l8 Q0 [/ F& K# t, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
6 o& ^  z7 m. z8 v5 f* K{
// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
& G0 \& T6 d6 H0 N2 {ASSERT( dwSize != -1 );
8 j/ n8 J" p, O: n4 l( D  j" o& b0 ~HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
9 N' K1 H8 N* b! \& h  EASSERT( hMemory != NULL );
& `6 i3 w6 }  d' c# x! \! sLPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
+ z5 X9 a" Z0 ~2 M) i* ]) sDWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
IStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
' R! a' O  t, B( j// 从流中装入图片
3 X0 Z6 z% D6 g/ N. `3 Z8 n; @8 k* iIPicture * pPicture = NULL;
% N2 S: D5 @3 s3 a/ V; Nif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
{
( P* a1 A' D+ R% O1 l// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
, h- P0 r& @' u! SOLE_YSIZE_HIMETRIC hmHeight;
3 b) K# E1 ^5 i0 q* D6 H. ipPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
; d3 c' y2 Y* q  d, DLL );
pPicture->Release();
}
// 释放流和文件
pStream->Release();
::CloseHandle( hFile );
}