[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
" D+ V9 N3 i- }2 V* V" Y% |- ^' AHDC hDC; // 绘图句柄
// 打开文件
HANDLE hFile;
if( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
& V. O; x  M' Z  ^) _" y) ) != INVALID_HANDLE_VALUE )
+ A6 P- V5 J# k0 u$ O& j3 {{
; m* i) C; ]3 t: \3 B// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
. v4 C; N. l! a2 {ASSERT( dwSize != -1 );
: L$ a" s7 c1 CHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
7 z# C; g" r3 x# q7 N9 J( gASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
# Q, C" I: b( X# O) uASSERT( pData != NULL );
- Q* ?. x# y9 qDWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
4 s7 V4 e9 Z' S4 |* v7 B/ [::GlobalUnlock( hMemory );
IStream * pStream = NULL;
- c. U" i3 S( ~! [0 g( f3 z::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
+ h* Q5 y  c7 eASSERT( pStream != NULL );
) S4 s0 v+ O# [4 g( ^9 K; H// 从流中装入图片
1 Z% }! f$ T, x8 S$ LIPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
0 `6 J  ~2 o9 w$ M7 u. d. U  uID* )&pPicture ) ) )
{
// 向DC中绘图
, w5 d' B+ X2 @& ^4 XOLE_XSIZE_HIMETRIC hmWidth;
5 p1 d+ L% D5 R! L3 N* EOLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
: ]  ~3 [% M2 WpPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
+ K2 Z+ Z3 @: n5 b: bLL );
pPicture->Release();
9 z- B/ r( D( L}
& X' `9 c; j3 y5 k% U// 释放流和文件
pStream->Release();
::CloseHandle( hFile );
9 J8 N" B0 Y0 A3 _! G}