mfc中如何解决屏幕闪烁

Question

void CTestView::OnDraw(CDC* pDC)
{
CTestDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here

CRect rect;
GetClientRect(&rect);//获取客户区大小



//画背景  棋盘等
static bool i=0;
if(!i)
{

    bmpbegin.LoadBitmap(IDB_BEGIN);
    begindc.CreateCompatibleDC(pDC);
    begindc.SelectObject(&bmpbegin);

    bmpend.LoadBitmap(IDB_END);
    enddc.CreateCompatibleDC(pDC);
    enddc.SelectObject(&bmpend);

    bmpback.LoadBitmap(IDB_BACK);
    backdc.CreateCompatibleDC(pDC);
    backdc.SelectObject(&bmpback);
    bmpback.GetBitmap(&backbmp);
    i=1;
}


pDC>StretchBlt(20,20,rect.Width()-130,rect.Height()-30,&backdc,0,0,backbmp.bmWidth,backbmp.bmHeight,SRCCOPY);
pDC->BitBlt(rect.Width()-100,70,100,50,&begindc,0,0,SRCCOPY);
pDC->BitBlt(rect.Width()-100,150,100,50,&enddc,0,0,SRCCOPY);

//棋盘坐标赋值
/*************************************************************************/
float mapw,maph;//格子长度
mapw =((float)rect.Width()-130.0)/14.0;
maph =((float)rect.Height()-30.0)/14.0;
int mapi,mapj;
for(mapi=0;mapi<15;mapi++)
{
    for(mapj=0;mapj<15;mapj++)
    {
        (mappoint[mapi][mapj]).x=20+mapi*mapw;
        (mappoint[mapi][mapj]).y=20+mapj*maph;
    }
}
/*************************************************************************/

//画棋子
CBrush backbrush(RGB(0,0,0));
CBrush whitebrush(RGB(255,255,255));
for(mapi=0;mapi<15;mapi++)
{
    for(mapj=0;mapj<15;mapj++)
    {
        if(backmap[mapi][mapj]||whitemap[mapi][mapj])
        {
            CPoint p1,p2;
            p1.x=mappoint[mapi][mapj].x-maph/2;
            p1.y=mappoint[mapi][mapj].y-maph/2;
            p2.x=mappoint[mapi][mapj].x+maph/2;
            p2.y=mappoint[mapi][mapj].y+maph/2;
            if(backmap[mapi][mapj])
                pDC->SelectObject(backbrush);
            if(whitemap[mapi][mapj])
                pDC->SelectObject(whitebrush);
            pDC->Ellipse(CRect(p1,p2));

        }
    }
}


if(1==chess%2)
    str="白棋走";
if(0==chess%2)
    str="黑棋走";
pDC->TextOut(rect.Width()-80,20,str);
str.Format("棋子数:%d",chess-1);
pDC->TextOut(rect.Width()-80,40,str);

}

Answer 1

解决屏幕闪烁问题，要用双缓冲技术，强调一下gdi+不支持双缓冲，gdi才支持。就是先再内存中画，然后再一次性画到屏幕上面，这样就避免屏幕设备不断出现白色屏幕的闪烁问题。