[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
- x% Y2 L% g/ Q' T2 c4 `HDC hDC; // 绘图句柄
: |( j9 J6 [& C7 o; T// 打开文件
HANDLE hFile;
if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
7 h8 B* h- N! |4 \4 t, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
5 F  s) F! ~1 @/ @) ) != INVALID_HANDLE_VALUE )
{
// 创建文件流
( y* P$ g6 p9 P" K2 H' aDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
* E* L( m0 M5 V# t6 h" s* bASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
DWORD dwCount;
3 v! }/ F+ C  k* C  \1 e+ M0 [  D::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
/ n! ?; d* O5 c1 ~' I4 |6 D' z' ~IStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
( ~8 n! C' }$ V5 \ASSERT( pStream != NULL );
// 从流中装入图片
6 m, C- K' ?  d- D  l' cIPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
, f8 _2 u/ W8 e; k+ _% X, t, DID* )&pPicture ) ) )
+ V. L6 v: g0 C: \/ z. s{
// 向DC中绘图
5 [3 g* \4 K1 w: cOLE_XSIZE_HIMETRIC hmWidth;
8 O( z  k8 y6 w( p) VOLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
8 [- z6 u* G- o& [0 spPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
, {0 F" T. m  h  N1 tpPicture->Release();
3 F. \# j; E) |}
' a  }' i. y! F3 h' ?// 释放流和文件
) m" G% z  p( M1 R1 O& {pStream->Release();
# H7 m1 X, W0 v0 @::CloseHandle( hFile );
8 a* d" }# Y/ [3 W) t. o}