gdi

Question

找了一些有关gdi的一些代码 其中加载图片的方式都是用LoadBitmap从资源里加载，我想从一个外部文件加载该如何实现呢？

Answer 1

改下下面代码中的路径，即可从你制定的路径载入JPG,JIF格式的图片 
IPicture   *pPicture;//声明OLE提供的图像对象
  IStream   *pStrm;//声明一个流对象   
        CFileStatus   fstatus;   
        CFile   file;   
        LONG   cb;   
        if((file.Open("D:/sunset.jpg",CFile::modeRead))&&(file.GetStatus("D:/sunset.jpg",fstatus))&&((cb=fstatus.m_size)!=-1))   
        {   
              HGLOBAL   hGlobal=GlobalAlloc(GMEM_MOVEABLE,cb);   
              LPVOID   pvData=NULL;   
              CDC   *pDC;   
              pDC=(this->GetActiveWindow())->GetDC();//得到活动视图的设备上下文   
              if(hGlobal!=NULL)   
              {   
                    if((pvData=GlobalLock(hGlobal))!=NULL)   
                    {   
                          file.Read(pvData,cb);//将图像文件数据读入内存   
                          GlobalUnlock(hGlobal);   
                          CreateStreamOnHGlobal(hGlobal,TRUE,&pStrm);//创建流对象   
                          if(SUCCEEDED(OleLoadPicture(pStrm,fstatus.m_size,TRUE,IID_IPicture,(LPVOID*)&pPicture)))   //根据流对象pStrm初始化图像对象pPicture   
                          {   
                                OLE_XSIZE_HIMETRIC   Width;   
                                OLE_YSIZE_HIMETRIC   Height;   
                                pPicture->get_Width(&Width);   
                                pPicture->get_Height(&Height);   
                                //得到图像的宽、高尺寸，注意该尺寸的逻辑单位不是图像的像素   
                                if(FAILED(pPicture->Render(*pDC,100,80,300,230,0,Height,Width,-Height,NULL)))
                                    //在初始点(100,80)宽为200、高为150的矩形中显示图形   
                                AfxMessageBox("Failed   to   render   the   picture"); 
                                pPicture->Release();   
                          }   
                          else   
                                AfxMessageBox("Error   loadimg   picture   from   stream!");   
                    }   
              }   
        }   
        else   
              AfxMessageBox("Can   open   image   file!");