rotatebutton.cpp

模拟了现实中的示波器

			lError -= --lXoffset * 2;

	} while (lYoffset <= lXoffset);	//Continue until halfway point
} 


/////////////////////////////////////////////////////////////////////////////
// CRotateButton

CRotateButton::CRotateButton()
{
	m_bDrawDashedFocusCircle = TRUE;
	m_bLighted = FALSE;
	m_nAngle = 0;
	m_bCapture = FALSE;
	m_dbMin = 0.0;
	m_dbMax = 1.0;
}

CRotateButton::~CRotateButton()
{
	m_rgn.DeleteObject();
}

BEGIN_MESSAGE_MAP(CRotateButton, CButton)
	//{{AFX_MSG_MAP(CRotateButton)
	ON_WM_LBUTTONDOWN()
	ON_WM_MOUSEMOVE()
	ON_WM_LBUTTONUP()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CRotateButton message handlers

void CRotateButton::PreSubclassWindow() 
{
	CButton::PreSubclassWindow();

	ModifyStyle(0, BS_OWNERDRAW);

	CRect rect;
	GetClientRect(rect);

	// Resize the window to make it square
	rect.bottom = rect.right = min(rect.bottom,rect.right);

	// Get the vital statistics of the window
	m_ptCentre = rect.CenterPoint();
	m_nRadius  = rect.bottom/2-1;

	// Set the window region so mouse clicks only activate the round section 
	// of the button
	m_rgn.DeleteObject(); 
	SetWindowRgn(NULL, FALSE);
	m_rgn.CreateEllipticRgnIndirect(rect);
	SetWindowRgn(m_rgn, TRUE);

	// Convert client coords to the parents client coords
	ClientToScreen(rect);
	CWnd* pParent = GetParent();
	if (pParent) pParent->ScreenToClient(rect);

	// Resize the window
	MoveWindow(rect.left, rect.top, rect.Width(), rect.Height(), TRUE);
}

void CRotateButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) 
{
	ASSERT(lpDrawItemStruct != NULL);
	
	CDC* pDC   = CDC::FromHandle(lpDrawItemStruct->hDC);
	CRect rect = lpDrawItemStruct->rcItem;
	UINT state = lpDrawItemStruct->itemState;
	UINT nStyle = GetStyle();
	int nRadius = m_nRadius;

	int nSavedDC = pDC->SaveDC();
	pDC->SelectStockObject(NULL_BRUSH);
	
	CBrush brush, *pBrush;
	brush.CreateSolidBrush(::GetSysColor(COLOR_BTNFACE));
	pBrush = pDC->SelectObject(&brush);
	pDC->Ellipse(rect);
	brush.DeleteObject();
	brush.CreateSolidBrush(::GetSysColor(COLOR_BTNFACE));
	pDC->SelectObject(&brush);
//	pDC->Ellipse(rect.left + 5, rect.top + 5, rect.right - 5, rect.bottom - 5);
	pDC->SelectObject(pBrush);

	// Draw the focus circle around the button
	//绘制有焦点时的外圆
	if(m_bCapture)
	{
		if ((state & ODS_FOCUS) && m_bDrawDashedFocusCircle)
			DrawCircle(pDC, m_ptCentre, nRadius--, RGB(0,0,255));
		nRadius -= 20;
	}
	// Draw the raised/sunken edges of the button (unless flat)
	if (nStyle & BS_FLAT) 
	{
//		DrawCircle(pDC, m_ptCentre, nRadius--, RGB(0,0,0));
//		DrawCircle(pDC, m_ptCentre, nRadius--, ::GetSysColor(COLOR_3DHIGHLIGHT));
	} 
	else 
	{
		if ((state & ODS_SELECTED))	
		{
			DrawCircle(pDC, m_ptCentre, nRadius--, 
					   ::GetSysColor(COLOR_3DDKSHADOW), ::GetSysColor(COLOR_3DHIGHLIGHT));
			DrawCircle(pDC, m_ptCentre, nRadius--, 
					   ::GetSysColor(COLOR_3DSHADOW), ::GetSysColor(COLOR_3DLIGHT));
			DrawCircle(pDC, m_ptCentre, nRadius--, 
					   ::GetSysColor(COLOR_3DSHADOW), ::GetSysColor(COLOR_3DLIGHT));
			DrawCircle(pDC, m_ptCentre, nRadius--, 
					   ::GetSysColor(COLOR_3DSHADOW), ::GetSysColor(COLOR_3DLIGHT));
		} 
		else 
		{


			DrawCircle(pDC, m_ptCentre, nRadius--,  
					   ::GetSysColor(COLOR_3DHIGHLIGHT), ::GetSysColor(COLOR_3DDKSHADOW));
			DrawCircle(pDC, m_ptCentre, nRadius--, 
					   ::GetSysColor(COLOR_3DLIGHT), ::GetSysColor(COLOR_3DSHADOW));
			DrawCircle(pDC, m_ptCentre, nRadius--, 
					   ::GetSysColor(COLOR_3DLIGHT), ::GetSysColor(COLOR_3DSHADOW));
			DrawCircle(pDC, m_ptCentre, nRadius--, 
					   ::GetSysColor(COLOR_3DLIGHT), ::GetSysColor(COLOR_3DSHADOW));

		}
	}
	DrawText(pDC, state);

	// Draw the focus circle on the inside of the button
	if ((state & ODS_FOCUS) && m_bDrawDashedFocusCircle)
//		DrawCircle(pDC, m_ptCentre, nRadius-2, RGB(0,0,0), TRUE);

	pDC->RestoreDC(nSavedDC);
}

void CRotateButton::SetLighted(BOOL b)
{
	m_bLighted = b;
	Invalidate();
}

void CRotateButton::DrawText(CDC *pDC, UINT state)
{
		// draw the text if there is any
	CString strText;
	GetWindowText(strText);
	CString s;
	s.Format("%2.1f", GetData());
	if (m_bCapture)
		strText = s;
	else
		strText += s;

	if (!strText.IsEmpty())
	{
		CRgn rgn;
		rgn.CreateEllipticRgn(m_ptCentre.x-m_nRadius, m_ptCentre.y-m_nRadius, 
							  m_ptCentre.x+m_nRadius, m_ptCentre.y+m_nRadius);
		pDC->SelectClipRgn(&rgn);

		CSize Extent = pDC->GetTextExtent(strText);
		CPoint pt = CPoint( m_ptCentre.x - Extent.cx/2, m_ptCentre.x - Extent.cy/2 );

		if (state & ODS_SELECTED) pt.Offset(1,1);

		pDC->SetBkMode(TRANSPARENT);
		pDC->SetTextColor(RGB(0,0,0));

		if (state & ODS_DISABLED)
			pDC->DrawState(pt, Extent, strText, DSS_DISABLED, TRUE, 0, (HBRUSH)NULL);
		else
			pDC->TextOut(pt.x, pt.y, strText);

		pDC->SelectClipRgn(NULL);
		rgn.DeleteObject();
	}


}

void CRotateButton::OnLButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	m_bCapture = TRUE;
	m_nAngle = GetAngle(point, m_ptCentre);
	SetCapture();
	CButton::OnLButtonDown(nFlags, point);
}

void CRotateButton::OnMouseMove(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	if (m_bCapture)
	{
		m_nAngle = GetAngle(point, m_ptCentre);
//		InvalidateRgn(&m_rgn, FALSE);
		Invalidate(FALSE);
	}
	CButton::OnMouseMove(nFlags, point);
}


int CRotateButton::GetAngle(CPoint ptCur, CPoint ptCenter)
{

	CPoint pt = ptCur - ptCenter;
	pt.y = -pt.y;
	//取得tan值
	double diff;
	if(pt.x == 0 && pt.y ==0)
	{
		diff = 0.0;return int(diff);
	}
	else if(pt.x == 0 && pt.y > 0)
	{	
		diff = 0.0;return int(diff);
	}
	else if(pt.x > 0 && pt.y ==0)
	{
		diff = 90;return int(diff);
	}
	else if(pt.x == 0 && pt.y < 0)
	{
		diff = 180;return int(diff);
	}
	else if(pt.x < 0 && pt.y == 0)
	{
		diff = 270;return int(diff);
	}

	diff = atan2(pt.y, pt.x);
	diff = diff * 180 / 3.14;

	//如果在第二象限，则用180－d1得到正确的度数
	//如果在第三象限，则用-180－d1得到正确的度数
	if (pt.x > 0 && pt.y > 0)
		diff = 90 - diff;
	else if (pt.x<0  && pt.y >0)
		diff = 360 - diff + 90;
	else if(pt.x<0 && pt.y<0)
		diff = 180 - (diff + 90);
	else if(pt.x > 0 && pt.y < 0)
		diff = 90 - diff;

	return int(diff);
}

void CRotateButton::OnLButtonUp(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	m_bCapture = FALSE;
	CButton::OnLButtonUp(nFlags, point);
}

void CRotateButton::SetRange(double min, double max)
{
	ASSERT(max > min);
	m_dbMin = min;
	m_dbMax = max;
}

double CRotateButton::GetData()
{
	return double(m_dbMin+(m_nAngle)*(m_dbMax - m_dbMin)/360.0);
}

void CRotateButton::SetData(double data)
{
	m_nAngle = int((data-m_dbMin) * 360.0 / (m_dbMax - m_dbMin));
	Invalidate();
}