//Check to see that the coordinates are valid
	ASSERT( (p.x + lRadius <= LONG_MAX) && (p.y + lRadius <= LONG_MAX) );
	ASSERT( (p.x - lRadius >= LONG_MIN) && (p.y - lRadius >= LONG_MIN) );

	//Set starting values
	lXoffset = lRadius;
	lYoffset = 0;
	lError   = -lRadius;

	do {
		const double Pi = 3.141592654, 
					 Pi_on_2 = Pi * 0.5,
					 Three_Pi_on_2 = Pi * 1.5;
		COLORREF crColour;
		double   dAngle = atan2(lYoffset, lXoffset);

		//Draw the current pixel, reflected across all four arcs

		crColour = GetColour(dAngle, crBright, crDark);
		pDC->SetPixelV(p.x + lXoffset, p.y + lYoffset, crColour);

		crColour = GetColour(Pi_on_2 - dAngle, crBright, crDark);
		pDC->SetPixelV(p.x + lYoffset, p.y + lXoffset, crColour);

		crColour = GetColour(-Pi_on_2 + dAngle, crBright, crDark);
		pDC->SetPixelV(p.x + lYoffset, p.y - lXoffset, crColour);

		crColour = GetColour(-dAngle, crBright, crDark);
		pDC->SetPixelV(p.x + lXoffset, p.y - lYoffset, crColour);

		//Advance the error term and the constant X axis step
		lError += lYoffset++;

		//Check to see if error term has overflowed
		if ((lError += lYoffset) >= 0)
			lError -= --lXoffset * 2;

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

// The original Drawcircle function is split up into DrawCircleRight and DrawCircleLeft
// to make stretched buttons
//
void CBtnEx::DrawCircleLeft(CDC* pDC, CPoint p, LONG lRadius, COLORREF crBright, COLORREF crDark)
{
	LONG lError, lXoffset, lYoffset;

	//Check to see that the coordinates are valid
	ASSERT( (p.x + lRadius <= LONG_MAX) && (p.y + lRadius <= LONG_MAX) );
	ASSERT( (p.x - lRadius >= LONG_MIN) && (p.y - lRadius >= LONG_MIN) );

	//Set starting values
	lXoffset = lRadius;
	lYoffset = 0;
	lError   = -lRadius;

	do {
		const double Pi = 3.141592654, 
					 Pi_on_2 = Pi * 0.5,
					 Three_Pi_on_2 = Pi * 1.5;
		COLORREF crColour;
		double   dAngle = atan2(lYoffset, lXoffset);

		//Draw the current pixel, reflected across all eight arcs

		crColour = GetColour(Pi_on_2 + dAngle, crBright, crDark);
		pDC->SetPixelV(p.x - lYoffset, p.y + lXoffset, crColour);

		crColour = GetColour(Pi - dAngle, crBright, crDark);
		pDC->SetPixelV(p.x - lXoffset, p.y + lYoffset, crColour);

		crColour = GetColour(-Pi + dAngle, crBright, crDark);
		pDC->SetPixelV(p.x - lXoffset, p.y - lYoffset, crColour);

		crColour = GetColour(-Pi_on_2 - dAngle, crBright, crDark);
		pDC->SetPixelV(p.x - lYoffset, p.y - lXoffset, crColour);

		//Advance the error term and the constant X axis step
		lError += lYoffset++;

		//Check to see if error term has overflowed
		if ((lError += lYoffset) >= 0)
			lError -= --lXoffset * 2;

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

/////////////////////////////////////////////////////////////////////////////
// CBtnEx

CBtnEx::CBtnEx()
{
	m_bDrawDashedFocusCircle = TRUE;
	m_bgTransparent = FALSE;
	m_3DText = FALSE;
	m_nBorder = 2;

	m_disParentRepaint = FALSE;

	m_pattern = patternRound;
	
	m_clr3dShadow = ::GetSysColor(COLOR_3DSHADOW);
	m_clr3dLight = ::GetSysColor(COLOR_3DLIGHT);
	m_clr3dDKShadow = ::GetSysColor(COLOR_3DDKSHADOW);
	m_clr3dHighLight = ::GetSysColor(COLOR_3DHIGHLIGHT);
	m_clrFaceN = ::GetSysColor(COLOR_BTNFACE);
	m_clrFaceS = m_clrFaceN;
	m_clrFaceH = m_clrFaceN;
	m_clrFaceD = m_clrFaceN;

	m_bHover = FALSE;
	m_bCapture = FALSE;
	m_bMouseDown = FALSE;
	m_enableHover = TRUE;
	m_enableFlat = FALSE;

	m_hCursor = NULL;
}

CBtnEx::~CBtnEx()
{
}

BEGIN_MESSAGE_MAP(CBtnEx, CButton)
	//{{AFX_MSG_MAP(CBtnEx)
	ON_WM_SIZE()
	ON_WM_ERASEBKGND()
	ON_WM_MOUSEMOVE()
	ON_WM_LBUTTONDOWN()
	ON_WM_LBUTTONUP()
	ON_WM_CREATE()
	ON_WM_SETCURSOR()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CBtnEx message handlers
void CBtnEx::OnSize( UINT nType, int cx, int cy )
{
	CButton::OnSize( nType, cx, cy );
	SetPattern( m_pattern );
}

void CBtnEx::OnLButtonDown(UINT nFlags, CPoint point) 
{
	// record that mouse is down
	m_bMouseDown = true;
	if (!m_bCapture) {
		SetCapture();
		m_bCapture = true;
	}
	CButton::OnLButtonDown(nFlags, point);
}

void CBtnEx::OnLButtonUp(UINT nFlags, CPoint point) 
{
	// record that mouse is released
	CButton::OnLButtonUp(nFlags, point);

	m_bMouseDown = false;	
	if (m_bCapture) {
		ReleaseCapture();
		m_bCapture = false;
	}
	CheckHover(point);
}

void CBtnEx::OnMouseMove(UINT nFlags, CPoint point) 
{
	// Test if mouse is above the button.
	if( !m_bMouseDown )
		CheckHover(point);

	CButton::OnMouseMove(nFlags, point);
}

void CBtnEx::PopupMenu(UINT menuID, int subMenuID/*=0*/)
{
/*	m_bMouseDown = false;	
	if (m_bCapture) {
		ReleaseCapture();
		m_bCapture = false;
	}
	m_bHover = false;
*/
	//準備彈出菜單的位置
CPoint point;
	{
	CRect rect;
	GetWindowRect(rect);
	point.x = rect.left;
	point.y = rect.bottom-3;
	}
	
CMenu menu;
CMenu* pPopup;
CWnd* pWndPopupOwner = this;

	VERIFY(menu.LoadMenu(menuID));
	pPopup = menu.GetSubMenu(subMenuID);
	ASSERT(pPopup != NULL);
	while (pWndPopupOwner->GetStyle() & WS_CHILD)
		pWndPopupOwner = pWndPopupOwner->GetParent();
	
	pPopup->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON,
		point.x, point.y, pWndPopupOwner);

	//復位鼠標，否則執行菜單后按鈕可能仍處于彈起狀態
	PostMessage( WM_LBUTTONUP, 0, 0 );
}

BOOL CBtnEx::OnSetCursor(CWnd* pWnd, UINT nHitTest, UINT message) 
{
	if( m_hCursor != NULL )
	{
		SetCursor( m_hCursor );
		::SetCursor( m_hCursor );
		return TRUE;
	}
	return CButton::OnSetCursor(pWnd, nHitTest, message);
}

void CBtnEx::CheckHover(CPoint point)
{
	if (HitTest(point))
	{
		if (!m_bCapture)
		{
			SetCapture();
			m_bCapture = true;
		}
		if ( !m_bHover && m_enableHover ) 
		{
			m_bHover = true;
			RedrawWindow();
		}
	}
	else
	{
		if (m_bCapture)
		{
			ReleaseCapture();
			m_bCapture = false;
		}
		m_bHover = false;
		RedrawWindow();
	}
}

BOOL CBtnEx::HitTest(CPoint point)
{
	return m_rgn.PtInRegion( point );
}

LRESULT CBtnEx::DefWindowProc(UINT message, WPARAM wParam, LPARAM lParam) 
{
	//引用自CBtnRgn
	// I have noticed that default windows buttons can be clicked very quickly.
	// Double or single click both result in a button being pushed down.
	// For owner drawn buttons this is not the case. Double click does
	// not push button down. Here is a solution for the problem:
	// double click message is substituted for single click.
	if (message == WM_LBUTTONDBLCLK)
		message = WM_LBUTTONDOWN;
	return CButton::DefWindowProc(message, wParam, lParam);
}

int CBtnEx::OnCreate(LPCREATESTRUCT lpCreateStruct) 
{
	if (CButton::OnCreate(lpCreateStruct) == -1)
		return -1;

	if( GetExStyle() & WS_EX_TRANSPARENT )
	{//如果窗口有透明屬性，則將本對象強制設置為透明屬性
		m_bgTransparent = TRUE;
	}
	else if( m_bgTransparent )
	{//如果用戶設置了透明屬性，則將窗口強制設置為透明屬性
		ModifyStyleEx( 0, WS_EX_TRANSPARENT );
	}

	SetPattern( m_pattern );

	return 0;
}

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

	//初始化參數
	m_bHover = FALSE;
	m_bCapture = FALSE;
	m_bMouseDown = FALSE;

	//設成自繪屬性以響應DrawItem()
	ModifyStyle(0, BS_OWNERDRAW);

	if( GetExStyle() & WS_EX_TRANSPARENT )
	{//如果窗口有透明屬性，則將本對象強制設置為透明屬性
		m_bgTransparent = TRUE;
	}
	else if( m_bgTransparent )
	{//如果用戶設置了透明屬性，則將窗口強制設置為透明屬性
		ModifyStyleEx( 0, WS_EX_TRANSPARENT );
	}

	SetPattern( m_pattern );
}

void CBtnEx::SetPattern( EBtnPat pattern )
{
	m_pattern = pattern;
	if( !::IsWindow( GetSafeHwnd() ) )
	{//窗口尚未建立
		return;
	}
	
CRect rect;
	GetClientRect(rect);

	if( m_pattern == patternRound )
	{// set m_bStretch if the button is not square and landscape 
		m_bStretch = rect.Width() > rect.Height();
	}
	else
	{
		m_bStretch = TRUE;
	}
	// Resize the window to make it square if it is not stretched
	if(!m_bStretch)	rect.bottom = rect.right = min(rect.bottom,rect.right);

	// Set the window region so mouse clicks only activate the rgn section 
	// of the button
	switch( m_pattern )
	{
	case patternRound:
		m_rgn.DeleteObject();
		{//計算圓按鈕，取圓與RECT的并集
		CRgn rgnRound;
		CRect rc, rc0( rect );
		int h = rect.Height();
			rc0.DeflateRect( 1, 1 );
			rc = rc0;
			rc.DeflateRect( h/2, 0 );
			m_rgn.CreateRectRgnIndirect( rc );
			rc = rc0;
			rc.right = rc.left + h;
			rgnRound.CreateEllipticRgnIndirect( rc );
			m_rgn.CombineRgn( &m_rgn, &rgnRound, RGN_OR );
			rc = rc0;
			rc.left = rc.right - h;
			rgnRound.DeleteObject();
			rgnRound.CreateEllipticRgnIndirect( rc );
			m_rgn.CombineRgn( &m_rgn, &rgnRound, RGN_OR );
		}
		break;
	case patternRect:
		m_rgn.DeleteObject();
		m_rgn.CreateRectRgnIndirect( rect );
		break;
	default://如果m_rgn存在則不改變
		if( m_rgn.GetSafeHandle() == NULL )
		{
			m_rgn.CreateRectRgnIndirect( rect );
		}
	}
	if( m_wndRgn.GetSafeHandle() == NULL )
	{
		m_wndRgn.CreateRectRgn( 0, 0, 0, 0 );
	}
	m_wndRgn.CopyRgn( &m_rgn );
	SetWindowRgn(NULL, TRUE);
	SetWindowRgn(m_wndRgn, TRUE);

	//Resize the window if it is not stretched
	if(!m_bStretch)
	{// Convert client coords to the parents client coords
	CWnd* pParent = GetParent();
		ClientToScreen(rect);
		if(pParent)
		{
			pParent->ScreenToClient(rect);
			MoveWindow(rect.left, rect.top, rect.Width(), rect.Height() );
		}
	}
	// Get the vital statistics of the window
	// m_ptLeft/m_ptRight are the centerpoints of the left/right arcs of stretched buttons
	m_rgn.GetRgnBox( rect );
	m_ptCentre = m_ptLeft = m_ptRight = rect.CenterPoint();

	m_nRadius  = rect.bottom/2-1;

	m_ptLeft.x = m_nRadius;
	m_ptRight.x = rect.right - m_nRadius - 1;
}

BOOL CBtnEx::SetFaceIMG(UINT bmpID, int cx, COLORREF mask)
{
CBitmap bmp;
	if( !bmp.LoadBitmap( bmpID ) )
	{
		return FALSE;
	}
	return SetFaceIMG( &bmp, cx, mask );
}

BOOL CBtnEx::SetFaceIMG( CBitmap * pBMP, int cx, COLORREF mask)
{
BITMAP sBMP;
	pBMP->GetBitmap( &sBMP );

	m_faceIMG.DeleteImageList();
	m_faceIMG.Create( cx, sBMP.bmHeight, ILC_COLOR24|ILC_MASK, 0, 1 );
	return ( m_faceIMG.Add( pBMP, mask ) >= 0 );
}

BOOL CBtnEx::NotifyParentRepaint( LPRECT rect)
{
	//這是實在不得已才用的方法：
	//本對象更新時，父窗口得不到更新，但父窗口更新時本對象自動更新
	//但本對象更新時，確實需要父窗口更新一次
	//如果不用disParentRepaint來鎖定，就會進入死循環
	if( !m_bgTransparent )
	{//不透明，不用通知父窗口，自己畫就行了
		return FALSE;
	}

	if( !m_disParentRepaint )
	{
		if( GetParent() != NULL )
		{
			MapWindowPoints( GetParent(), rect );
			m_disParentRepaint = TRUE;
			GetParent()->InvalidateRect( rect ); 
			return TRUE;
		}
		else
		{
			return FALSE;
		}
	}
	else
	{
		m_disParentRepaint = FALSE;
		return FALSE;
	}
}

void CBtnEx::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) 
{
	ASSERT(lpDrawItemStruct != NULL);
	if( NotifyParentRepaint( &(lpDrawItemStruct->rcItem) ) )
	{//已通知父窗口重畫，自己暫時不用畫，等父窗口發來的信號再畫
		return;
	}

CDC * pDC = CDC::FromHandle(lpDrawItemStruct->hDC);
CRect rect = lpDrawItemStruct->rcItem;
UINT state = lpDrawItemStruct->itemState;
int nRadius = m_nRadius;

	pDC->SelectClipRgn(&m_rgn);
	DrawItemBG( pDC, state, rect, nRadius );//畫背景
	DrawItemFace( pDC, state, rect, nRadius );//畫表面
	pDC->SelectClipRgn( NULL );
	DrawItemBorder( pDC, state, rect, nRadius );//畫邊框
}

void CBtnEx::DrawItemFace( CDC * pDC, UINT state, CRect & rect, int & nRadius )
{
	if( m_faceIMG.GetSafeHandle() != NULL
	 && m_faceIMG.GetImageCount() > 0 )
	{
		DrawFaceIMG( pDC, state, rect, nRadius );
	}
	else
	{
		DrawFaceText( pDC, state, rect, nRadius );
	}
}

void CBtnEx::DrawItemBorder( CDC * pDC, UINT state, CRect & rect, int & nRadius )
{
	if( !(state & ODS_SELECTED) && !m_bHover )
	{//不是按下或彈起狀態
		if( m_enableFlat )
		{//使用平面按鈕，不畫邊框
			return;
		}
	}
	switch( m_pattern )
	{
	case patternRound:
		DrawBorderRound( pDC, state, rect, nRadius );
		break;
	case patternRect:
		DrawBorderRect( pDC, state, rect, nRadius );
		break;
	default:
		DrawBorderOther( pDC, state, rect, nRadius );
	}
}

void CBtnEx::DrawItemBG(CDC * pDC, UINT state, CRect & rect, int & nRadius )
{
	if( !m_bgTransparent )
	{
	COLORREF clr;
		if( state & ODS_DISABLED )
			clr = m_clrFaceD;
		else if( state & ODS_SELECTED )
			clr = m_clrFaceS;
		else if( m_bHover )
			clr = m_clrFaceH;
		else 
			clr = m_clrFaceN;
		pDC->FillSolidRect(rect, clr);
	}
}

void CBtnEx::DrawFaceText(CDC * pDC, UINT state, CRect & rect, int & nRadius )
{
	// draw the text if there is any
CString strText;
	GetWindowText(strText);
	if( strText.IsEmpty() )
	{
		return;
	}

UINT nStyle = GetStyle();

CSize Extent = pDC->GetTextExtent(strText);
	if( strText.Find( '&' ) >= 0 )
	{//有&符號
	CSize ex = pDC->GetTextExtent( "&" );
		Extent.cx -= ex.cx;
	}