VC++实现画线
实现画线的原理就是记录起点和终点，用起点和终点画线.以下程序中m_ptOrigin为在手标按下的消息Function里保存的手标按下时的坐标
void CDrawDlg::OnLButtonUp(UINT nFlags, CPoint point) //手标起来的消息
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
m_pMouseDown = false;
CDC *pDC = GetDC();
CPen pen;
pen.CreatePen(PS_SOLID,3,RGB(201,150,50));
CPen* old_Pen = pDC->SelectObject(&pen);
/*
//填充位图
CBitmap bitmap;
bitmap.LoadBitmap(IDB_BITMAP1);
CBrush brush(&bitmap);
pDC->FillRect(CRect(m_ptOrigin,point),&brush);
*/
//填充颜色
CBrush brush(RGB(100,240,125));
pDC->FillRect((CRect(m_ptOrigin,point)),&brush);
//创建一个空画刷，此空画刷画出的矩形是透明的
CBrush *brush2 = CBrush::FromHandle((HBRUSH)GetStockObject(NULL_BRUSH));
CBrush* old_brush = pDC->SelectObject(brush2);
pDC->Rectangle(CRect(m_ptOrigin,point));
pDC->SelectObject(old_brush);
// 画线条
pDC->MoveTo(m_ptOrigin);
pDC->LineTo(point);
pDC->SelectObject(old_Pen);
ReleaseDC(pDC);
/*
CWindowDC dc(GetDesktopWindow());
CPen pen;
pen.CreatePen(PS_SOLID,3,RGB(255,0,0));
CPen* oldPen = dc.SelectObject(&pen);
dc.MoveTo(m_ptOrigin);
dc.LineTo(point);
dc.SelectObject(oldPen);
*/
CDialog::OnLButtonUp(nFlags, point);
}
