[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
' T5 V4 m' b& _! XHDC hDC; // 绘图句柄
' y1 _& Z5 ~! R" H// 打开文件
HANDLE hFile;
1 h/ P- P- m& B8 f* Lif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
3 R1 r5 U( Z- ~# @, N{
7 M1 E7 H/ @3 a// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
! q! p  f- ?, M1 j( L+ tASSERT( hMemory != NULL );
, }7 {  ^: ]0 }8 [, ]: }LPVOID pData = ::GlobalLock( hMemory );
7 |# j7 z2 ^/ e, v1 Q3 MASSERT( pData != NULL );
" s  X  I+ Y/ |! ?, t( {- H* |DWORD dwCount;
8 T2 y" o+ {, s" t8 w& ^% U::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
7 @3 X  H$ G6 M) YIStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
/ m6 ]; k9 ~; N// 从流中装入图片
3 n' {4 M' C2 a- A  Y6 xIPicture * pPicture = NULL;
  w$ P# o( Z/ \5 s) |* F" vif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
- U& z# D2 V/ s* A% g{
/ V2 E' R8 c2 L2 F" L* a// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
4 q4 L  O* y' s/ DpPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
  M4 _' k$ v, N$ W, PpPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
  }7 }1 C/ c' E7 Z9 p! R8 x- J- jLL );
: `0 l) w2 T" h9 j0 H! spPicture->Release();
5 S- \: C( F5 i}
// 释放流和文件
* f# R: S% u3 N3 r6 ~pStream->Release();
::CloseHandle( hFile );
% x( N+ w8 \/ o: [}