[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
6 J. p: l, @0 ZHDC hDC; // 绘图句柄
& q. j! n: \4 l- _// 打开文件
HANDLE hFile;
5 M7 C% r* x& s& E# [1 Aif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
7 t, m8 }7 l) n, q, o1 C, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
/ s4 n* |% R$ W8 z8 \) ) != INVALID_HANDLE_VALUE )
& \" R) G( A2 p- t* w{
// 创建文件流
" x8 c7 `* l; o. K" j) M6 |( eDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
: z4 b; W9 G0 Q* hASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
( Z/ k/ g5 l5 B+ i' kDWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
2 L/ n1 g1 ^' C2 a4 i( c- Z::GlobalUnlock( hMemory );
IStream * pStream = NULL;
/ S$ [* l  \' s. q- I: z" D: I0 q) h::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
// 从流中装入图片
IPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
{
1 O* t  C* m  ^- E// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
, h( {& y+ v# @pPicture->get_Width( &hmWidth );
  n. E& D7 g0 Z. T) dpPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
+ b, o+ ^7 {! e$ M- A6 B; {+ Z0 W9 qpPicture->Release();
. M, q& I8 B. |& u. E8 v}
7 f) G! P8 L/ Y* s// 释放流和文件
: o7 v( _3 L" m, w, A1 Q# c: @pStream->Release();
::CloseHandle( hFile );
}