[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
9 c, a$ T3 x& x1 Y0 g' ]/ X/ H( L+ VHDC hDC; // 绘图句柄
* S6 u; P7 D( H/ T// 打开文件
HANDLE hFile;
/ h+ e2 \8 a1 e4 _# Yif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
5 M3 n& A  v2 P% W- l2 D{
' v9 ^; T* p; _) i: j// 创建文件流
4 M# g. r( F* \4 cDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
' m' k0 g& x2 q7 O5 @ASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
. A1 `3 B/ C. uASSERT( hMemory != NULL );
8 Z$ C. f% ?7 K0 OLPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
DWORD dwCount;
4 _+ Y  o( g# S7 ?::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
' V* y& U/ {4 K0 h$ o0 ~% |IStream * pStream = NULL;
! O" |; j3 D' {6 ], x+ n8 P::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
' b5 `1 ~' P' Z9 C7 }ASSERT( pStream != NULL );
// 从流中装入图片
IPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
: C8 `, \$ f! `ID* )&pPicture ) ) )
{
% V1 R5 s6 j2 E( l// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
# Q# I7 O3 m; qOLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
, {3 H8 v0 W2 _( [pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
0 T1 L; t5 }8 }; l/ Z3 W0 m+ FpPicture->Release();
}
3 _# A/ X/ S: o) u8 ?// 释放流和文件
6 u1 O# |: L$ o% h0 H: r9 epStream->Release();
7 }' e: ~  \) G3 K8 v' Z::CloseHandle( hFile );
: Q& @+ O" S5 s}