[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
; y6 X) M2 [0 W/ sHANDLE hFile;
% b# {. A# {: M/ d' j; [% Rif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
! @5 O3 m: F8 W/ i) |$ ^, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
, r( u# M* l, \) ) != INVALID_HANDLE_VALUE )
; j# Z/ ^6 t* ^! s3 m{
// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
5 P& u) H& [3 EHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
* Z5 I% I4 U8 cLPVOID pData = ::GlobalLock( hMemory );
' h6 o7 l. z' U, x4 q0 mASSERT( pData != NULL );
( T4 z4 Q5 M$ P; X, Z3 p0 F" R9 k3 W& nDWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
IStream * pStream = NULL;
" x0 u: U, A: }& c  |::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
// 从流中装入图片
/ s  z# I$ u0 v9 V* A; A, \IPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
+ Y$ {% r* B* JID* )&pPicture ) ) )
{
// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
$ {6 O  [2 L& @% q7 gpPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
: V+ Q+ F: p* ^; x+ L& fLL );
pPicture->Release();
}
// 释放流和文件
# \, e. ~! T9 i, H, n2 g: X- N  upStream->Release();
::CloseHandle( hFile );
5 L+ Y' O( x  w% K; F; s1 Z) K' u}