C / C++ / MFC

void CMyClass::OnDraw(CDC* pDC)
{
  //No code
}

void CMyClass::OnErase(CDC* pDC)
{
  CMemDC buff(pDC);

  buff.LineTo(100, 100);

  //I can't remember if I called the default OnErase 

  CView::OnErase(pDC);

  return FALSE;
}

BOOL CRulerView::OnEraseBkgnd(CDC* pDC)
{ 
	CMemDC buff(pDC);

	//Drawing area
	CRect rect;	
	GetClientRect(&rect);

	//Draw ruler background
	buff.FillSolidRect(0, 0, m_rulerSize, rect.bottom, ::GetSysColor(COLOR_BTNFACE));
	buff.FillSolidRect(0, 0, rect.right, m_rulerSize, ::GetSysColor(COLOR_BTNFACE));
	
	//window borders width
	UINT nBorderWidth = ::GetSystemMetrics(SM_CXEDGE);

	//Draw 3D border, blends with parent window
	if(m_b3Dborder){
		buff.DrawEdge(CRect(0, 0, rect.right, m_rulerSize), EDGE_RAISED, BF_RIGHT | BF_TOP);
		buff.DrawEdge(CRect(0, 0, m_rulerSize, rect.bottom), EDGE_RAISED , BF_LEFT | BF_BOTTOM);
	}

	//Draw border edge
	buff.DrawEdge(CRect(m_rulerSize-nBorderWidth, m_rulerSize-nBorderWidth, rect.right, rect.bottom), EDGE_SUNKEN, BF_TOP | BF_LEFT);

	//Draw the rulers
	OnDrawRuler(&buff, CRect(nBorderWidth*2, m_rulerSize-nBorderWidth, m_rulerSize-(nBorderWidth*2), rect.bottom-m_nScrSize+nBorderWidth),  RT_VERT);
	OnDrawRuler(&buff, CRect(m_rulerSize-nBorderWidth, nBorderWidth*2, rect.right-m_nScrSize+nBorderWidth, m_rulerSize-(nBorderWidth*2)), RT_HORZ);

	//Draw the cursor tracker out of bounds
	OnMouseMove(NULL, CPoint(-10,-10));	
	
	return FALSE; 
}

void CRulerView::OnDraw(CDC* pDC)
{
}