[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
2 |: {5 M7 K& g! ?: u* p$ M// 打开文件
) }" S" J& ]8 C5 HHANDLE hFile;
& V+ n5 \$ Q  b- [  J6 h% Y3 Rif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
$ c  i- M* \6 z9 s/ ^, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
+ j# s+ D" T/ C$ f" Y8 a# B6 X) ) != INVALID_HANDLE_VALUE )
4 \( R4 [1 {" D{
// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
; m/ s- g/ _6 e# [3 [! zASSERT( dwSize != -1 );
HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
0 A" N4 L! N. ?# O6 ]LPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
7 A. q7 S" N6 t9 k+ MDWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
IStream * pStream = NULL;
1 I# K0 s6 R/ B' u  O0 E5 T::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
ASSERT( pStream != NULL );
* T9 x9 N9 d+ j" g// 从流中装入图片
IPicture * pPicture = NULL;
  s5 ]+ V0 C" S: G; J2 E6 rif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
{
// 向DC中绘图
! `3 J6 s( B! z+ a4 S- u% p3 H8 sOLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
. D: z1 w0 z2 @: W. b5 D! z8 p  HpPicture->get_Width( &hmWidth );
' \/ M" Y. K( Y; ^( W* zpPicture->get_Height( &hmHeight );
. Y0 `  }' _, ?! Y) z1 o, V) OpPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
8 U2 A7 `! i: N7 M) ~LL );
pPicture->Release();
}
// 释放流和文件
/ U0 X1 Y3 ^! u9 L' Z8 ]$ \pStream->Release();
3 b! l# d6 N& B  }. C::CloseHandle( hFile );
  t+ y6 O1 t( d}