[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
- D- m0 ~: X# F6 D$ r) s3 |+ `( ?HDC hDC; // 绘图句柄
// 打开文件
  w% B7 M* k4 g9 uHANDLE hFile;
( }) ]# W/ h* Z9 nif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
6 e/ ^! E1 h8 y2 w# C% q, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
: i) [4 Q- c: |, g{
5 x% k- Z8 ~9 E4 r/ i// 创建文件流
# B" `, W% N: q/ c% _7 ^" o* UDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
8 N7 ~% W8 z7 z: M3 ]0 e; WHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
# ]  y$ ~& H7 ~ASSERT( hMemory != NULL );
9 J9 d2 N6 Q' w, w  Y& ^LPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
DWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
/ @! u1 H9 a* j& G9 K::GlobalUnlock( hMemory );
IStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
; S! M0 Z4 K0 v& t; |+ K# J. oASSERT( pStream != NULL );
3 @5 O; d+ y8 p) K8 N1 f5 p0 M// 从流中装入图片
IPicture * pPicture = NULL;
/ V: s5 y6 t% [/ I  c9 }3 zif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
( z4 h; t/ R1 |. {6 aID* )&pPicture ) ) )
! d$ @* j& y4 T; y" E$ Y$ G/ K{
// 向DC中绘图
$ u2 b: i. Y4 j0 q$ jOLE_XSIZE_HIMETRIC hmWidth;
( Z' d1 L  p" L" ]OLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
+ e& R9 ~# R/ _3 \2 X9 wpPicture->get_Height( &hmHeight );
1 i3 V4 Q  @! z( S% U1 [pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
* E& u2 X+ U  V0 r# apPicture->Release();
* l+ W+ g4 c0 U" ]}
- k; d' e6 f, X) y8 m6 I) q// 释放流和文件
- ]& k+ q* i6 D- _) l4 H. b1 y# ]' OpStream->Release();
( z2 R  d+ ^4 A+ E  [9 x( O::CloseHandle( hFile );
}