27.8 Mouse Events (cont.)

• Depending on the number of corners that have already been specified, the paint handler draws
  • a small circle for the first mouse click
  • a line after the first two mouse clicks
  • a triangle after three mouse clicks

void TriangleWindow::OnPaint(wxPaintEvent & event)
{
   const int RADIUS = 2;
   wxPaintDC(this);
   if (corners == 1)
      dc.DrawEllpse(x[0] - RADIUS, y[0] - RADIUS,
         2 * RADIUS, 2 * RADIUS);
   if (corners >= 2)
      dc.DrawLine(x[0], y[0], x[1], y[1]);
   if (corners >= 3)
   {
      dc.DrawLine(x[1], y[1], x[2], y[2]);
      dc.DrawLine(x[2], y[2], x[0], y[0]);
   }
}

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