一个画线问题
CBrush newbrush(RGB(0,0,0));
CPen newpen(PS_DASH,1,RGB(255,255,255));
CBrush* oldbrush=pDC->SelectObject (&newbrush);
CPen* oldpen=pDC->SelectObject (&newpen);
pDC->MoveTo (0,0);
pDC->LineTo (200,200);
pDC->SelectObject (oldbrush);
pDC->SelectObject (oldpen);
在黑色的背景上画,结果不是虚线,请问大侠这是怎么回事?