[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
8 m2 h  G# _) b// 打开文件
1 t; G! T! R0 J" r! o+ R3 P5 jHANDLE hFile;
if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
/ e  P5 L/ z' n" M{
// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
, b1 h6 z& R. [8 l; \5 F- X9 D% vHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
0 T' L/ t2 C2 @, P( a( gASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
( r: i8 X2 U6 _8 t7 @' {ASSERT( pData != NULL );
DWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
2 I% }1 B7 z* X  x# h$ F2 }7 d7 F6 Q::GlobalUnlock( hMemory );
  o; B) A  {" LIStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
  O) H& p, J" X: X2 U; y8 SASSERT( pStream != NULL );
// 从流中装入图片
IPicture * pPicture = NULL;
: C: {: ~2 {  D& kif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
{
// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
& M' g! b9 F+ P4 q# T+ |4 Y  }OLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
4 N- B9 i2 Q) d4 C3 A4 _( |5 o7 P8 PpPicture->get_Height( &hmHeight );
4 @& }0 |8 r6 k; NpPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
pPicture->Release();
}
1 o4 U8 p! n( J' k// 释放流和文件
pStream->Release();
* u3 T6 B1 G$ s( e! P. G' ^::CloseHandle( hFile );
}