修改如下:
void CEx01View::OnDraw(CDC* pDC)
{
CEx01Doc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here
CBrush brush(RGB(255,0,0));
CBrush *pOldBrush=pDC->SelectObject(&brush);
pDC->MoveTo(0,0);//线是两个端点的
pDC->LineTo(700,600);
pDC->Rectangle(&m_position);
pDC->SelectObject(pOldBrush);
pDC->TextOut(100,100,"Hello!");
}
void CEx01View::OnDraw(CDC* pDC)
{
CEx01Doc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here
CBrush brush(RGB(255,0,0));
CBrush *pOldBrush=pDC->SelectObject(&brush);
pDC->MoveTo(0,0);//线是两个端点的
pDC->LineTo(700,600);
pDC->Rectangle(&m_position);
pDC->SelectObject(pOldBrush);
pDC->TextOut(100,100,"Hello!");
}
我试过如果画矩形如pDC->Rectangle(0,0,700,600);在移动小矩形时也不会擦去前面的大矩形。
请问:原理是怎样的,画线时起点终点要明确,那画其他几何图形时呢?