[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
0 m" q0 R  J4 D  N( rHDC hDC; // 绘图句柄
// 打开文件
HANDLE hFile;
if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
8 a0 s7 a- w( T# d, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
2 z: x; `% j( o. R! I) E1 c# J) ) != INVALID_HANDLE_VALUE )
- p8 G! {. ^" i" q7 `  m# E{
9 i3 Y9 M- U, u// 创建文件流
9 T7 g2 b, ^! P5 @& k# N) b! M3 tDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
. ~% u) q0 ]- a) w+ k/ L% J) fASSERT( hMemory != NULL );
7 z$ G/ i/ f# |( f; N' _) yLPVOID pData = ::GlobalLock( hMemory );
: D9 L& C) k6 @& _; W# a; n! mASSERT( pData != NULL );
! K! V  u0 A, ~% N9 R0 MDWORD dwCount;
9 ^  ]- f. v# I. }4 Q5 B0 o::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
5 l& Z1 J# u2 F4 [! e$ Q::GlobalUnlock( hMemory );
IStream * pStream = NULL;
& ?; U' `! d/ F$ E" U5 ~::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
. u5 ?; P$ ?+ X; R% _& `. N- qASSERT( pStream != NULL );
0 ?) v1 W; |- |3 v% t// 从流中装入图片
IPicture * pPicture = NULL;
0 k7 i5 x# Z5 A  L. b9 rif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
5 s+ T0 D0 @+ H  i1 h( CID* )&pPicture ) ) )
7 z6 G- L  d6 c{
9 A! \4 \3 k/ H5 R3 c3 q+ ]// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
3 \2 R$ d2 `' Z8 D1 Y5 B% VOLE_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();
}
5 W% y5 H* q- g// 释放流和文件
pStream->Release();
* N5 X+ i/ h3 s::CloseHandle( hFile );
}