OnPrepareDC的用法,有没有人能给我打个比方,这个东西是做什么用的,
CClientDC dc(this);OnPrepareDC(&dc);
CRect rectDevice = m_rectEllipse;
dc.LPtoDP(rectDevice);
if (rectDevice.PtInRect(point)) {
if (m_nColor == GRAY_BRUSH) {
m_nColor = WHITE_BRUSH;
}
else {
m_nColor = GRAY_BRUSH;
}
InvalidateRect(rectDevice);
}