如何在控件上加载jpeg图象

[chongwenwang]

如何将jpeg格式的图象转换成bmp图象在控件上显示出来

[mxm324]

一般你可以用一些写好的类库做这些事情,,如:CXImage 可以到www.codeproject.com.
不过你也可以自己研究jpeg的编码格式..自己写转换的...

[ToperRay]

CXImage

display函数

[Kudeet]

void   CMenuDlg::LoadPictureFromFile(LPCTSTR   szFile,   CBitmap   *pBitmap)//szFile是jpg文件名，打开时最好到debug目录下，避免路径错误   
  {   
          //   open   file   
          HANDLE   hFile   =   CreateFile(szFile,   GENERIC_READ,   0,   NULL,   OPEN_EXISTING,   0,   NULL);   
        //   _ASSERTE(INVALID_HANDLE_VALUE   !=   hFile);   
    
          //   get   file   size   
          DWORD   dwFileSize   =   GetFileSize(hFile,   NULL);   
          _ASSERTE(-1   !=   dwFileSize);   
    
          LPVOID   pvData   =   NULL;   
          //   alloc   memory   based   on   file   size   
          HGLOBAL   hGlobal   =   GlobalAlloc(GMEM_MOVEABLE,   dwFileSize);   
          _ASSERTE(NULL   !=   hGlobal);   
    
          pvData   =   GlobalLock(hGlobal);   
          _ASSERTE(NULL   !=   pvData);   
    
          DWORD   dwBytesRead   =   0;   
          //   read   file   and   store   in   global   memory   
          BOOL   bRead   =   ReadFile(hFile,   pvData,   dwFileSize,   &dwBytesRead,   NULL);   
          _ASSERTE(FALSE   !=   bRead);   
          GlobalUnlock(hGlobal);   
          CloseHandle(hFile);   
    
          LPSTREAM   pstm   =   NULL;   
          //   create   IStream*   from   global   memory   
          HRESULT   hr   =   CreateStreamOnHGlobal(hGlobal,   TRUE,   &pstm);   
          _ASSERTE(SUCCEEDED(hr)   &&   pstm);   
    
          //   Create   IPicture   from   image   file   
          LPPICTURE   gpPicture;   
    
          hr   =   ::OleLoadPicture(pstm,   dwFileSize,   FALSE,   IID_IPicture,   (LPVOID   *)&gpPicture);           
            
          _ASSERTE(SUCCEEDED(hr)   &&   gpPicture);           
          pstm->Release();   
    
          OLE_HANDLE   m_picHandle;   
            
          gpPicture->get_Handle(&m_picHandle);   
          pBitmap->DeleteObject();   
          pBitmap->Attach((HGDIOBJ)   m_picHandle);   
    
            
  }

[lyg_zy]

用GDI+显示吧。要求开发环境.net2003以上。示例代码如下：

#include "atlImage.h"
/**
* 在目标DC的目标矩形rc中显示pJpeg文件的JPEG图象，并保存为bmp
*/
void DisplayJpeg( char *pJpgeFile,HDC hdc,RECT & rc )
{	 

	/**
	* imag对象从pJpgeFile文件中加载图像并绘制到目标DC的目标矩形rc中
	*/
	CImage imag;
	imag.Load( pJpgeFile );
	imag.Draw( hdc, rc );

	/**
	* 保存为bmp图片
	*/
	imag.Save( "c:\\1.bmp" );

}