balloontip.cpp

操作系统实验演示代码(三个实验

{
	if (CFrameWnd::OnCreate(lpCreateStruct) == -1)
    {
        return -1;
    }
	
    // Remove caption and thick frame for proper shading
    ModifyStyle(WS_CAPTION | WS_THICKFRAME, 0); 

    CRect t_Rect;
	GetClientRect(&t_Rect);  // Get the client rectangle to set the balloon region

    if (m_bBalloonUp)
    {
        // Calculation of Text window, where to write text in the balloon
        m_rectText.left   = t_Rect.Width() * 0.10; 
        m_rectText.right  = t_Rect.Width() * 0.90;
        m_rectText.top    = t_Rect.Height() * 0.10; 
        m_rectText.bottom = t_Rect.Height()* 0.70; 
            	
        // Create an elliptical region out of the client rectangle
	    m_rgnRoundRect.CreateRoundRectRgn(
            t_Rect.left, 
            t_Rect.top, 
            t_Rect.right,
            t_Rect.bottom - (t_Rect.Height() * 0.25), 
            abs(t_Rect.left - t_Rect.right) * 0.18,
            t_Rect.Height() * 0.25
        );
   
        // Start the process of creating the balloon tip
	    CPoint ptTri[4];
	    ptTri[0].x = (t_Rect.left) + (t_Rect.Width() * 0.93);
	    ptTri[0].y = (t_Rect.bottom) - (t_Rect.Height() * 0.40);
    
	    ptTri[1].x = (t_Rect.left) + (t_Rect.Width() * 0.65);
	    ptTri[1].y = t_Rect.bottom;

	    ptTri[2].x = (t_Rect.left) + (t_Rect.Width() * 0.70);
	    ptTri[2].y = (t_Rect.bottom) - (t_Rect.Height() * 0.40);
   
	    ptTri[3].x = (t_Rect.left) + (t_Rect.Width() * 0.93);
	    ptTri[3].y = (t_Rect.bottom) - (t_Rect.Height() * 0.40);
   
	    m_rgnTip.CreatePolygonRgn(ptTri, 3, ALTERNATE);
    }
    else
    {
        // Calculation of Text window, where to write text in the balloon
        m_rectText.left   = t_Rect.Width() * 0.10;
        m_rectText.right  = t_Rect.Width() * 0.90;
        m_rectText.top    = t_Rect.Height() * 0.30;
        m_rectText.bottom = t_Rect.Height() * 0.90;
        
        // Create an elliptical region out of the client rectangle
	    m_rgnRoundRect.CreateRoundRectRgn(
            t_Rect.left,
            t_Rect.bottom - (t_Rect.Height() * 0.75), 
            t_Rect.right, 
            t_Rect.bottom, 
            abs(t_Rect.left - t_Rect.right) * 0.18,
            t_Rect.Height() * 0.25
        );

        // Start the process of creating the balloon tip
	    CPoint ptTri[4];
	    ptTri[0].x = (t_Rect.left) + (t_Rect.Width() * 0.07);
	    ptTri[0].y = (t_Rect.Height() * 0.40);
            
	    ptTri[1].x = (t_Rect.left) + (t_Rect.Width() * 0.35);
	    ptTri[1].y = t_Rect.bottom - t_Rect.Height();

	    ptTri[2].x = (t_Rect.left) + (t_Rect.Width() * 0.30);
	    ptTri[2].y = t_Rect.Height() * 0.40;
           
	    ptTri[3].x = (t_Rect.left) + (t_Rect.Width() * 0.07);
	    ptTri[3].y = t_Rect.Height() * 0.40;
           
	    m_rgnTip.CreatePolygonRgn(ptTri, 3, ALTERNATE);
    }
    
    // Create the combined region with ellipse and tip
	CRgn rgnComb;	
    
    rgnComb.CreateRectRgn(t_Rect.left, t_Rect.top, t_Rect.right, t_Rect.bottom);
		
	int iRetComb = rgnComb.CombineRgn(&m_rgnTip, &m_rgnRoundRect, RGN_OR);
	
    if (iRetComb == ERROR)
	{
        ::AfxMessageBox( "ERROR in Combining Region" );
		return -1;
	}
   
    SetWindowRgn(rgnComb.operator HRGN(), TRUE);
	
	return 0;
}




/*-----------------------------------------------------------------------------
 Function : CBalloonTip::OnPaint()

 Created: Nov 1, 2001
 Author:  Prateek Kaul
 e-mail:  [e-mail]

 Abstract : Gets called by MFC for a WM_PAINT message

 Parameters : 
        See MFC documentation

 Return Value : void

 Exceptions : none

 Revisions : none
----------------------------------------------------------------------------*/

void CBalloonTip::OnPaint() 
{
	CPaintDC dc(this); // device context for painting

    CRect t_Rect;
    GetClientRect(&t_Rect);

    // Get the total balloon, inclding all cut out regions
	CRgn rgnComb;	
    rgnComb.CreateRectRgn(t_Rect.left, t_Rect.top, t_Rect.right, t_Rect.bottom);
   
    // Create a balloon tip from this total region
    int iRetComb = rgnComb.CombineRgn(&m_rgnTip, &m_rgnRoundRect, RGN_OR );
    if (iRetComb == ERROR)
	{
        ::AfxMessageBox( "ERROR in Combining Region" );
        return;
	}

	CBrush brOutlineBrush;
    brOutlineBrush.CreateSolidBrush(RGB(0, 0, 0)); // blue
   
    CBrush brFillBrush;
    brFillBrush.CreateSolidBrush(RGB(249, 254, 188)); // light yellow
   
   
    dc.FillRgn(&rgnComb, &brFillBrush);  // Fill the balloon
    dc.FrameRgn(&rgnComb, &brOutlineBrush, 2, 1); // Outline the balloon

    int nBkMode          = dc.SetBkMode(TRANSPARENT);
    COLORREF clrPrevious =  dc.SetTextColor(RGB(255, 0, 0));
    CFont *pFont = dc.SelectObject(&m_fontBalloonText);
   
    CSize czTextWidth = dc.GetTextExtent(m_strMessage);
   
    if (czTextWidth.cx < m_rectText.Width())
    {
       dc.DrawText(m_strMessage, m_rectText, DT_CENTER | DT_VCENTER | DT_SINGLELINE);
    }
     
    else
    {
        dc.DrawText(m_strMessage, m_rectText, DT_CENTER | DT_WORDBREAK);
    }
    
    // Restore the DC to its oroginal state
    dc.SelectObject(pFont);
    dc.SetBkColor(nBkMode);
    dc.SetTextColor(clrPrevious);
}




/*-----------------------------------------------------------------------------
 Function : CBalloonTip::PreCreateWindow(CREATESTRUCT& cs)

 Created: Dec 07, 2001
 Author:  Prateek Kaul
 e-mail:  [e-mail]

 Abstract : Called by MFC when a before WM_CREATE message is received by the
            window.

            We override this function so that the window so created is not
            visible in the Taskbar. We make this window the child of an
            invisible parent m_wndInvisibleParent.

 Parameters : Look in MFC documentation

 Return Value : BOOL

 Exceptions : none

 Revisions : none
----------------------------------------------------------------------------*/

BOOL CBalloonTip::PreCreateWindow(CREATESTRUCT& cs)
{
	if (!CWnd::PreCreateWindow(cs))
    {
		return FALSE;
    }

 	// Create invisible parent window
 	if (!::IsWindow(m_wndInvisibleParent.m_hWnd))
 	{
        // Try creating the invisible parent window
        PCSTR pstrOwnerClass = ::AfxRegisterWndClass(0);
       
        BOOL bError = m_wndInvisibleParent.CreateEx(
                          0,
                          pstrOwnerClass, 
                          _T(""), 
                          WS_POPUP,
				          0,
                          0,
                          0,
                          0,
				          NULL,
                          0
                      );

        if (bError == FALSE)
        {
			return FALSE;
        }
 	}

    // Set the invisible window as the parent of "this" window
	cs.hwndParent = m_wndInvisibleParent.m_hWnd;

	return TRUE;
}




/*-----------------------------------------------------------------------------
 Function : CBalloonTip::Create()

 Created: Dec 07, 2001
 Author:  Prateek Kaul
 e-mail:  [e-mail]

 Abstract : Called by the static CBalloonTip to create a Windows(R) window 

 Parameters : rect-> a rectangle in screen co ordinates where the balloon
              will be displayed.

 Return Value : BOOL

 Exceptions : none

 Revisions : none
----------------------------------------------------------------------------*/

BOOL CBalloonTip::Create(CRect rect)
{
    m_rectWindow = rect;

    PCSTR pstrOwnerClass = ::AfxRegisterWndClass(0);
    BOOL bResult = CFrameWnd::Create(pstrOwnerClass, NULL, WS_OVERLAPPED, m_rectWindow);
    
    return bResult;
}





/*-----------------------------------------------------------------------------
 Function : CBalloonTip::Hide()

 Created: Dec 08, 2001
 Author:  Prateek Kaul
 e-mail:  [e-mail]

 Abstract : Provided to destroy a balloon before it self destructs. If it is 
            already hidden, it will have no effect.
            
 Parameters : CBalloonTip*

 Return Value : void

 Exceptions : none

 Revisions : none
----------------------------------------------------------------------------*/

void CBalloonTip::Hide(CBalloonTip* pBalloonTip)
{
    if (CBalloonTip::nBalloonInstances != 0)
    {
        pBalloonTip->ShowWindow(SW_HIDE);
        pBalloonTip->KillTimer(ID_TIMER);
        pBalloonTip->DestroyWindow();
    }
}




/*-----------------------------------------------------------------------------
  int CBalloonTip::nBalloonInstances;

  Abstract: Used for preventing more than one instance of the class CBalloonTip
-----------------------------------------------------------------------------*/

int CBalloonTip::nBalloonInstances = 0;




/*-----------------------------------------------------------------------------
 Function : CBalloonTip::PostNcDestroy()

 Created: Dec 08, 2001
 Author:  Prateek Kaul
 e-mail:  [e-mail]

 Abstract : Last function the window receives when it is destroyed.
            Used for resetting the counter CBalloonTip::nBalloonInstances to 0,
            so that a new instance of this class can be created.
            
 Parameters : void

 Return Value : void

 Exceptions : none

 Revisions : none
----------------------------------------------------------------------------*/

void CBalloonTip::PostNcDestroy()
{
    CBalloonTip::nBalloonInstances = 0;
    CFrameWnd::PostNcDestroy();
}