[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
& S% b# ~, t/ i* w$ ~7 `HANDLE hFile;
if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
* [. r* C1 z2 e/ g, S: u% Y, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
  F4 I  a: l) F; M3 ~1 I: K  z3 `; E{
// 创建文件流
8 W6 \. O! _# z; W1 ?% uDWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
! q$ P. Q3 s: ?! o' _HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
/ L" O+ Z3 _: [1 K' @ASSERT( hMemory != NULL );
; |% }4 j  j; [LPVOID pData = ::GlobalLock( hMemory );
. C# ]6 r3 U6 u' F' z' `8 bASSERT( pData != NULL );
0 g- L% q2 ^* dDWORD dwCount;
5 `& f, u* a1 K4 W5 y7 d::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
& u* y( o* l. ]::GlobalUnlock( hMemory );
IStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
* ?- X- l+ X: Z5 E- r. L" |ASSERT( pStream != NULL );
// 从流中装入图片
  c, ^8 I6 b7 C6 ?5 c) H; vIPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
3 G* Z0 u  |6 O: |4 o5 z{
: k5 E; _; X& g: m. T6 u// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
! F2 \4 @) e3 ZpPicture->get_Height( &hmHeight );
; {$ U5 Y3 T0 B4 Z$ r  E: C7 ]pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
% h7 J$ |( O2 D+ P1 yLL );
pPicture->Release();
}
+ z5 }( [8 d' X3 W8 e7 B  u; A// 释放流和文件
pStream->Release();
8 ^; g" D6 u* U$ }0 z; Z::CloseHandle( hFile );
- W7 ?' D* e! I" O0 h. m# I}