[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
$ v' V# A' i$ R) j// 打开文件
HANDLE hFile;
if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
2 G8 }( p& e- M, H0 M' h) ) != INVALID_HANDLE_VALUE )
{
, j# S; p3 {" O0 v1 w  _2 n& h7 b! H// 创建文件流
) o! X4 A, C# A0 ?: L# KDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
) R4 N5 G* e# m( K% o1 cASSERT( dwSize != -1 );
' U9 M) W% v: c$ s- B8 x. ^/ G7 Y( vHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
9 f4 o1 v8 M4 Y7 \1 mASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
DWORD dwCount;
  K3 P& d0 @; o% ?::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
IStream * pStream = NULL;
/ R' w3 y' m) e( k* U% Q::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
) `" e8 n9 g& W9 a. w! A) ^ASSERT( pStream != NULL );
  h, z  n( v, g# k// 从流中装入图片
IPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
9 e1 [8 o/ Z% X2 BID* )&pPicture ) ) )
{
# F" R2 E" v! G( `4 O// 向DC中绘图
+ S& K- s! \' v# d! [$ e8 B# XOLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
0 j3 b# P2 I+ M  S+ n0 l9 T+ GpPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
  K, B: V! o3 `% a: j& k5 j: G! GpPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
# x% t6 A0 L$ A# R+ G( qLL );
pPicture->Release();
1 S' [" ]+ Z5 U% n# B- L}
) \/ p. q; w0 K6 j// 释放流和文件
! K9 O$ a- `& X$ |( OpStream->Release();
::CloseHandle( hFile );
4 y& P) K( m7 m- u$ k}