www.pudn.com > 《MFC Windows程序设计(第二版)》.rar > MouseCap.cpp, change:1998-09-25,size:3264b

#include <afxwin.h> 
#include "MouseCap.h" 
 
CMyApp myApp; 
 
///////////////////////////////////////////////////////////////////////// 
// CMyApp member functions 
 
BOOL CMyApp::InitInstance () 
{ 
    m_pMainWnd = new CMainWindow; 
    m_pMainWnd->ShowWindow (m_nCmdShow); 
    m_pMainWnd->UpdateWindow (); 
    return TRUE; 
} 
 
///////////////////////////////////////////////////////////////////////// 
// CMainWindow message map and member functions 
 
BEGIN_MESSAGE_MAP (CMainWindow, CFrameWnd) 
    ON_WM_LBUTTONDOWN () 
    ON_WM_LBUTTONUP () 
    ON_WM_MOUSEMOVE () 
    ON_WM_NCLBUTTONDOWN () 
END_MESSAGE_MAP () 
 
CMainWindow::CMainWindow () 
{ 
    m_bTracking = FALSE; 
    m_bCaptureEnabled = TRUE; 
 
	// 
	// Register a WNDCLASS. 
	// 
    CString strWndClass = AfxRegisterWndClass ( 
        0, 
        AfxGetApp ()->LoadStandardCursor (IDC_CROSS), 
        (HBRUSH) (COLOR_WINDOW + 1), 
        AfxGetApp ()->LoadStandardIcon (IDI_WINLOGO) 
    ); 
 
	// 
	// Create a window. 
	// 
    Create (strWndClass, _T ("Mouse Capture Demo (Capture Enabled)")); 
} 
 
void CMainWindow::OnLButtonDown (UINT nFlags, CPoint point) 
{ 
	// 
	// Record the anchor point and set the tracking flag. 
	// 
    m_ptFrom = point; 
    m_ptTo = point; 
    m_bTracking = TRUE; 
 
	// 
	// If capture is enabled, capture the mouse. 
	// 
    if (m_bCaptureEnabled) 
        SetCapture (); 
} 
 
void CMainWindow::OnMouseMove (UINT nFlags, CPoint point) 
{ 
	// 
	// If the mouse is moved while we're "tracking" (that is, while a 
	// line is being rubber-banded), erase the old rubber-band line and 
	// draw a new one. 
	// 
    if (m_bTracking) { 
        CClientDC dc (this); 
        InvertLine (&dc, m_ptFrom, m_ptTo); 
        InvertLine (&dc, m_ptFrom, point); 
        m_ptTo = point; 
    } 
} 
 
void CMainWindow::OnLButtonUp (UINT nFlags, CPoint point) 
{ 
	// 
	// If the left mouse button is released while we're tracking, release 
	// the mouse if it's currently captured, erase the last rubber-band 
	// line, and draw a thick red line in its place. 
	// 
    if (m_bTracking) { 
        m_bTracking = FALSE; 
        if (GetCapture () == this) 
            ::ReleaseCapture (); 
 
        CClientDC dc (this); 
        InvertLine (&dc, m_ptFrom, m_ptTo); 
 
        CPen pen (PS_SOLID, 16, RGB (255, 0, 0)); 
        dc.SelectObject (&pen); 
 
        dc.MoveTo (m_ptFrom); 
        dc.LineTo (point); 
    } 
} 
 
void CMainWindow::OnNcLButtonDown (UINT nHitTest, CPoint point) 
{ 
	// 
	// When the window's title bar is clicked with the left mouse button, 
	// toggle the capture flag on or off and update the window title. 
	// 
    if (nHitTest == HTCAPTION) { 
        m_bCaptureEnabled = m_bCaptureEnabled ? FALSE : TRUE; 
        SetWindowText (m_bCaptureEnabled ? 
            _T ("Mouse Capture Demo (Capture Enabled)") : 
            _T ("Mouse Capture Demo (Capture Disabled)")); 
    } 
    CFrameWnd::OnNcLButtonDown (nHitTest, point); 
} 
 
void CMainWindow::InvertLine (CDC* pDC, CPoint ptFrom, CPoint ptTo) 
{ 
	// 
	// Invert a line of pixels by drawing a line in the R2_NOT drawing mode. 
	// 
    int nOldMode = pDC->SetROP2 (R2_NOT); 
 
    pDC->MoveTo (ptFrom); 
    pDC->LineTo (ptTo); 
 
    pDC->SetROP2 (nOldMode); 
}