为什么反色模式没效果？

Question

CWindowDC dc(NULL);
dc.MoveTo(0,0);
dc.LineTo(3000,3000); dc.SetROP2(R2_XORPEN),
dc.MoveTo(0,0);
dc.LineTo(3000,3000);

Answer 1

你把dc.SetROP2(R2_XORPEN)放在CWindowDC dc(NULL)后面试试

Answer 2

我想先画条线，在檫掉。
CWindowDC dc(NULL);
dc.MoveTo(0,0);
dc.LineTo(3000,3000);         sleep(1000); dc.SetROP2(R2_XORPEN);
dc.MoveTo(0,0);
dc.LineTo(3000,3000);

Answer 3

CWindowDC dc(NULL);
dc.SetROP2(R2_NOT);
dc.MoveTo(0,0);
dc.LineTo(3000,3000);
Sleep(2000);
dc.MoveTo(0,0);
dc.LineTo(3000,3000);