[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;
$ p9 F1 T" {. b8 o$ iif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
& s5 r' z' ^5 T7 G: d2 `6 j, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
9 b" V. R4 E2 a3 m. b- B) ) != INVALID_HANDLE_VALUE )
) K- m; u, l8 C) q* d{
// 创建文件流
DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
ASSERT( dwSize != -1 );
. L: B2 Z/ @8 B0 J$ k  \/ g! ZHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
ASSERT( pData != NULL );
DWORD dwCount;
::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
::GlobalUnlock( hMemory );
: k- M& w) D: O1 f1 JIStream * pStream = NULL;
4 u9 ^* k0 }! q" d6 ?! V::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
0 y6 ]' z. }7 e& S8 HASSERT( pStream != NULL );
- h' `1 r4 P5 d3 @/ a+ ]/ D9 ?& M0 ]// 从流中装入图片
  V2 i& n' I6 d& M4 r8 `- PIPicture * pPicture = NULL;
if( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
( Y" v6 Y0 t& y$ J, n# jID* )&pPicture ) ) )
{
// 向DC中绘图
# \. ?+ j; D7 i( C" q! X* H& L, g$ k. M0 {OLE_XSIZE_HIMETRIC hmWidth;
0 D7 |' Q  n+ c. U7 G! S3 dOLE_YSIZE_HIMETRIC hmHeight;
pPicture->get_Width( &hmWidth );
( C. [. N( w* o3 M( R& [- @pPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
1 s0 j* A" V9 \  a7 P# Q5 MLL );
pPicture->Release();
}
1 g# n0 B0 d. T; g/ `  w// 释放流和文件
" A) G- k2 j7 H' KpStream->Release();
::CloseHandle( hFile );
0 P% ?7 h& d% Q; n}