[收藏]读取JPEG和GIF图像的简单方法

天云上人

CString strName; // 文件名
! p7 R" S' |$ w" x8 W( u, |( ?0 vHDC hDC; // 绘图句柄
4 g4 N  i; Q, J; B; a8 K1 P6 K% z// 打开文件
* N# @% n" q! }0 lHANDLE hFile;
+ q, r, H. m+ J  F5 I0 v; Qif( ( hFile = ::CreateFile( strName ,true ) ), GENERIC_READ, FILE_SHARE_READ
, L) f' n. p. \- G, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN, NULL
) ) != INVALID_HANDLE_VALUE )
{
// 创建文件流
. E5 U$ c$ h  _1 x' D* ?DWORD dwSize = DWORD( ::GetFileSize( hFile, NULL ) );
; t; U: X8 q, M2 f; S# R; C" CASSERT( dwSize != -1 );
# @3 R" v5 j+ q% }4 w" Z  Y) f, hHGLOBAL hMemory = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
ASSERT( hMemory != NULL );
LPVOID pData = ::GlobalLock( hMemory );
2 t+ R, k+ O" r2 l, i; ~- ?% c+ NASSERT( pData != NULL );
DWORD dwCount;
7 K2 w- M8 W: I$ r::ReadFile( hFile, pData, dwSize, &dwCount, NULL );
; N+ B( L: V) Q# B+ N::GlobalUnlock( hMemory );
IStream * pStream = NULL;
::CreateStreamOnHGlobal( hMemory, TRUE, &pStream );
* o* s+ {3 k) lASSERT( pStream != NULL );
" |6 y; l* J: O! }4 Z8 I, w# m// 从流中装入图片
IPicture * pPicture = NULL;
; W5 x) L6 \! t% Xif( SUCCEEDED( ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture,( LPVO
ID* )&pPicture ) ) )
{
& K4 z  {0 a% l! n7 R  J- i// 向DC中绘图
OLE_XSIZE_HIMETRIC hmWidth;
, T: J1 W, p( H1 b  Q4 UOLE_YSIZE_HIMETRIC hmHeight;
4 \% y. q2 \! x3 {8 PpPicture->get_Width( &hmWidth );
pPicture->get_Height( &hmHeight );
pPicture->Render( hDC, 0, 0, 300, 300, 0, hmHeight, hmWidth, -hmHeight, NU
LL );
: }+ i5 C' q4 S7 l: spPicture->Release();
; A- B  g8 b, E6 u- ]}
// 释放流和文件
( m6 q3 k- V7 d% V1 k! OpStream->Release();
::CloseHandle( hFile );
}