[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
HANDLE hFile;
# x6 w9 W; C' ?if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
( M, O, s( I* J. T) o7 B1 N) ) != INVALID_HANDLE_VALUE )
{
' U' Q+ L' @/ X// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
3 c$ w% S) H0 o( X- x% x+ _HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
6 y) A9 [$ j5 ^1 gASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
, V3 A' l& M1 yASSERT( pData != NULL );
; k- A( J4 F& R- k" ^4 n9 x4 IDWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
0 q$ I5 x  B( G: Y2 R* C7 d::GlobalUnlock( hMemory );
# a5 R2 t6 r9 C3 Y. A: h% E9 xIStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
. v( S& z9 ?( G// 从流中装入图片
4 ?; R) }* A# Y! Z: T+ OIPicture * pPicture = NULL;
& m6 E7 U: }/ b5 e: Q+ M1 M5 H+ x; @if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
/ ?% T" M4 A* J2 t0 E$ A, ^/ yID* )&pPicture ) ) )
& C) K, n+ ?/ \+ V{
// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
0 ^% h& ^( P8 q- G4 bOLE_YSIZE_HIMETRIC hmHeight;
( i# Y" R: B# m5 O1 DpPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
pPicture->Release();
}
// 释放流和文件
# n# ?: [( N2 o2 T' NpStream->Release();
::CloseHandle( hFile );
8 F; p1 J) M( F+ C& s0 H}