如何在程序运行中打开一幅图片

Question

就是运行程序后，选“文件”->“打开”，然后选择路径导入一幅图片，而不是在编写时导入一个固定位置的图片

Answer 1

BOOLShowPIC(CDC *pDC, CString strPath, CRect rect,int ShowType)
{
CPen newpen(PS_DOT,1,RGB(255,255,255));
CPen *pOldPen=pDC->SelectObject(&newpen);
pDC->Rectangle(rect);
pDC->SelectObject(pOldPen);

//显示BMP JPG GIF等格式的图片
    IStream *pStm;  
    CFileStatus fstatus;
    CFile file;  
    LONG cb;  

HGLOBAL hGlobal;
    //打开文件并检测文件的有效性
    if (file.Open(strPath,CFile::modeRead)&&
        file.GetStatus(strPath,fstatus)&& 
        ((cb = fstatus.m_size) != -1)) 
    {  

        hGlobal = GlobalAlloc(GMEM_MOVEABLE, cb); 
        LPVOID pvData = NULL;  
        if (hGlobal != NULL)  
        {  
            pvData = GlobalLock(hGlobal);
            if (pvData != NULL)  
            {  
                file.ReadHuge(pvData, cb);  
                GlobalUnlock(hGlobal);  
                CreateStreamOnHGlobal(hGlobal, TRUE, &pStm);  
            } 
        } 
    }
    else
    {
        return false;
    } 
//打开文件结束
    

    //显示JPEG和GIF格式的图片，GIF只能显示一帧，还不能显示动画，
//要显示动画GIF请使用ACTIVE控//件。

    IPicture *pPic; 
    //load image from file stream

    if(SUCCEEDED(OleLoadPicture(pStm,fstatus.m_size,TRUE,IID_IPicture,(LPVOID*)&pPic))) 
    { 
        OLE_XSIZE_HIMETRIC hmWidth;  
        OLE_YSIZE_HIMETRIC hmHeight; 
        pPic->get_Width(&hmWidth);  
        pPic->get_Height(&hmHeight);
        double fX,fY;  
        //得到图片的高度与宽度
        fX = (double)pDC->GetDeviceCaps(HORZRES)*(double)hmWidth/
((double)pDC->GetDeviceCaps(HORZSIZE)*100.0);  
        fY = (double)pDC->GetDeviceCaps(VERTRES)*(double)hmHeight/
((double)pDC->GetDeviceCaps(VERTSIZE)*100.0);  

long nwidth,nheight,nleft,ntop;
int Rx,Ry;
Rx=rect.Width();
Ry=rect.Height();
nheight=Ry;
nwidth=Rx;
nleft=rect.left;
ntop=rect.top;
//检测显示模式
//是否拉伸充满区域显示
if(ShowType==1)
{
nheight=Ry;
nwidth=Rx;
nleft=rect.left;
ntop=rect.top;
}
//是否居中且按正常比例显示
else if(ShowType==2)
{
if(fX<Rx) nwidth=(long)fX;
if(fY<Ry)     nheight=(long)fY;

if((fY>Ry)||(fX>Rx))
{
double temp,temp2;
temp=Ry/fY;
temp2=Rx/fX;
if(temp<temp2)
{
nwidth=(long)(fX*temp);
nleft=(Rx-nwidth)/2+rect.left;
}
else if(temp>=temp2)
{
nheight=(long)(fY*temp2);
ntop=(Ry-nheight)/2+rect.top;
}
}
}


        //用 Render函数显示图片
        //if(FAILED(pPic->Render(*pDC,rect.left,rect.top ,rect.Width(),rect.Height(),0,
if(FAILED(pPic->Render(*pDC,nleft,ntop,nwidth,nheight,0,
hmHeight,hmWidth,-hmHeight,NULL)))  
        {
            pPic->Release();
            return false;
        }
           pPic->Release();  
    }  

    else  
    {
        return false;  
    }
//释放内存
    GlobalUnlock(hGlobal);  
GlobalFree(hGlobal);      return true;}