[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
// 打开文件
HANDLE hFile;
1 _# t7 T6 k$ d; d1 c7 [if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
+ ]' m* ]0 b( l# p" |  e$ ?" E/ F, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
{
// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
" d9 H6 J# r& ~3 p8 T  nASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
& `: `3 G7 _" u* F% e' JASSERT( pData != NULL );
DWORD dwCount;
" K% z7 L! X  I6 A2 P  U' d::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
: _1 v$ [9 h% {::GlobalUnlock( hMemory );
& o/ g/ s4 n0 _& h1 E$ oIStream * pStream = NULL;
, `2 T1 ?5 S# G::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
$ R/ L+ U- ^& L& K# n4 a// 从流中装入图片
IPicture * pPicture = NULL;
4 f( ]' {" q3 wif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
" Q0 i6 V3 L5 o2 {3 N8 G8 D{
6 b  r) m0 |- o2 ~; t- G" Q$ z0 W// 向DC中绘图
+ ^5 M2 {" S) uOLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
5 A; \/ B3 A! b+ U6 q; {pPicture->get_Width( &hmWidth );
% M! H* i+ h; O+ W1 Z% ApPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
3 b0 V2 O5 N* |LL );
pPicture->Release();
: ~3 f8 b; U1 W1 i2 R9 ~3 s2 w}
, W- G$ w. [7 W( C/ p( i// 释放流和文件
pStream->Release();
! g) z' E% Y2 L4 I8 ?::CloseHandle( hFile );
}