[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
, L' @; v, v8 e- i, gHDC hDC; // 绘图句柄
// 打开文件
3 b$ Q/ }# _+ h# j3 EHANDLE hFile;
8 Z, t3 a, [; {: k2 Cif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
( U3 K& b: o+ U8 r; M" D" {) ) != INVALID_HANDLE_VALUE )
: P% Y0 p$ }9 Y/ e5 e) k& P{
' u/ i) {! a1 S% O# |, ?// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
, ]9 ]2 c8 m; x8 \ASSERT( dwSize != -1 );
2 k! m. h  d; F' ]HGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
- R" [+ F+ R5 m6 SASSERT( pData != NULL );
DWORD dwCount;
+ i% |; s' K/ q' x8 _- H4 h::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
+ m/ h$ g! |" \3 R, c( X::GlobalUnlock( hMemory );
2 Z4 U  D5 j0 W6 K0 F8 q$ E, LIStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
$ _* G2 Y$ W6 L) uASSERT( pStream != NULL );
// 从流中装入图片
IPicture * pPicture = NULL;
) ]) Y2 X! g1 B! _if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
2 X& i3 c7 }4 }! s7 J5 L{
// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
2 |% q8 r! x7 h! l' rpPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
% O3 \; `  l9 t' T7 JLL );
2 o, q3 O% m1 f7 QpPicture->Release();
1 W6 \3 z$ N8 ^2 K}
6 V8 ^* B2 g7 N9 z0 _: U9 z// 释放流和文件
pStream->Release();
  e1 ~; I% q8 s3 `::CloseHandle( hFile );
! f7 A5 D: T3 U  p}