[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
7 b3 q  z, N; J, F& x$ kHDC hDC; // 绘图句柄
1 w' {! f% X* q& }// 打开文件
HANDLE 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 )
{
// 创建文件流
: a/ o* j9 w  YDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
  A: T& R7 h5 q8 gASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
* ]7 y4 |, b, d, V0 ?% g2 jLPVOID pData = ::GlobalLock( hMemory );
( A! H. t# B8 U' z2 h  ~, O, \ASSERT( pData != NULL );
DWORD dwCount;
6 k, n6 d3 I7 F  G0 f::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
; `3 j+ z6 x4 E0 m, q1 S2 ]* |::GlobalUnlock( hMemory );
% \7 s, l( g6 v" J; ^IStream * pStream = NULL;
4 y2 P) h8 n9 H. ]0 u::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
& X# I; b  Z9 K, V5 [. b// 从流中装入图片
IPicture * pPicture = NULL;
5 X0 R7 _  ?4 O" o2 j5 {6 ~: S* @& Aif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
5 k# z7 {( V8 |8 L2 [- v2 a+ h) R{
2 r$ I% @% m! K6 m( O// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
; ]" I! s( ?0 g* k9 z/ d* W* oOLE_YSIZE_HIMETRIC hmHeight;
7 n' J8 F4 a" [- C+ j# ?5 Q: ypPicture->get_Width( &hmWidth );
* q9 l4 R, q2 J8 k1 _( [) rpPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
, l# W- K* m+ M" ~6 ipPicture->Release();
}
' @* k/ u2 w: x7 T8 U0 _3 t// 释放流和文件
pStream->Release();
1 l$ b$ L3 j! W' g& E; p::CloseHandle( hFile );
}