Tricks of the Windows Gam…ming Gurus (2nd Edition)/Disc2.iso/msdn_vcb/samples/vc98/mfc/advanced/mtmdi/bounce.cpp

C/C++ Source or Header | 1998-03-27 | 13.6 KB | 453 lines

// bounce.cpp : Defines the class behaviors for the Bounce child window.
//
// This is a part of the Microsoft Foundation Classes C++ library.
// Copyright (C) 1992-1998 Microsoft Corporation
// All rights reserved.
//
// This source code is only intended as a supplement to the
// Microsoft Foundation Classes Reference and related
// electronic documentation provided with the library.
// See these sources for detailed information regarding the
// Microsoft Foundation Classes product.

#include "stdafx.h"
#include "mdi.h"
#include "bounce.h"
#include "mtbounce.h"

#define ABS(x) ((x) < 0? -(x) : (x) > 0? (x) : 0)

BEGIN_MESSAGE_MAP(CBounceMDIChildWnd, CMDIChildWnd)
    //{{AFX_MSG_MAP(CBounceMDIChildWnd)
    ON_WM_SIZE()
    //}}AFX_MSG_MAP
    ON_MESSAGE(WM_USER_PREPARE_TO_CLOSE, OnPrepareToClose)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CBounceMDIChildWnd

CMenu CBounceMDIChildWnd::menu;        // menu for all BOUNCE windows

CBounceMDIChildWnd::CBounceMDIChildWnd()
{
}

BOOL CBounceMDIChildWnd::Create(LPCTSTR szTitle, LONG style /* = 0 */,
    const RECT& rect /* = rectDefault */,
    CMDIFrameWnd* parent /* = NULL */)
{
    // Setup the shared menu
    if (menu.m_hMenu == NULL)
        menu.LoadMenu(IDR_BOUNCE);
    m_hMenuShared = menu.m_hMenu;

    if (!CMDIChildWnd::Create(NULL, szTitle, style, rect, parent))
        return FALSE;

    // The default PostNcDestroy handler will delete this CBounceMDIChildWnd
    // object when destroyed.  When Windows destroys the CBounceMDIChildWnd
    // window, it will also destroy the CBounceWnd, which is the child
    // window of the MDI child window, executing in the separate thread.
    // Finally, when the child CBounceWnd window is destroyed, the
    // CWinThread object will be automatically destroyed, as explained
    // in the comment for CBounceThread::InitInstance in mtbounce.cpp.

    CBounceThread* pBounceThread = new CBounceThread(m_hWnd);
    pBounceThread->CreateThread();

    return TRUE;
}


BOOL CBounceMDIChildWnd::OnCmdMsg(UINT nID, int nCode, void* pExtra,
        AFX_CMDHANDLERINFO* pHandlerInfo)
{
    // The default CFrameWnd::OnCmdMsg function is responsible for
    // dispatching menu commands to ON_COMMAND handlers and for
    // initializing menus and toolbars via ON_UPDATE_COMMAND_UI
    // handlers.  For the MDI child window, all such dispatching
    // and command user interface initialization are done in the
    // main application thread.  The CBounceWnd object processes
    // user interface events in a separate thread.  This override,
    // CBounceMDIChildWnd::OnCmdMsg, delegates command handling to
    // the child CBounceWnd window.  It cannot do this delegation
    // by simply calling CBounceWnd::OnCmdMsg, because doing so
    // would defeat the design of handling CBounceWnd user interface
    // events in the separate thread.  If CBounceMDIChildWnd::OnCmdMsg
    // simply called CBounceWnd::OnCmdMsg, then the command handling
    // would be processed in the same main application thread as that
    // of the MDI child window.
    //
    // A common and safe way to make a call from one thread to another
    // is to call SendMessage for a window whose message pump runs in
    // a second thread.  That is how CBounceMDIChildWnd::OnCmdMsg is
    // implemented.  All of the OnCmdMsg parameters are gathered into
    // an application-defined (but re-usable) COnCmdMsg structure,
    // that is sent by reference to the CBounceWnd window via the
    // lParam of SendMessage.


    CWnd* pBounceWnd = (CBounceWnd*)GetDlgItem(IDC_BOUNCE_WND);
    if (pBounceWnd == NULL)
        return FALSE; // child CBounceWnd not created yet.

    // It is safe to create the COnCmdMsg on the stack because
    // it will not be deleted until the SendMessage call has
    // synchronously executed.

    COnCmdMsg oncmdmsg;
    oncmdmsg.m_nID =    nID;
    oncmdmsg.m_nCode = nCode;
    oncmdmsg.m_pExtra = pExtra;
    oncmdmsg.m_pHandlerInfo = pHandlerInfo;

    // In addition to passing all of the OnCmdMsg parameters to
    // the CBounceWnd window via the SendMessage lParam, it is also
    // necessary to forward the implicit wParam originally passed
    // in the WM_COMMAND message for the menu command.  The original
    // WM_COMMAND wParam is not a parameter of OnCmdMsg, but it can
    // be obtained by calling GetCurrentMessage.  The wParam is needed by
    // the CBounceWnd::OnColor command handler to distinguish which
    // menu item, i.e., which color, was selected from the Color menu.
    //
    // The original single thread MDI sample application, the
    // CBounceWnd::OnColor command handler calls GetCurrentMessage
    // to retrieve the wParam from the WM_COMMAND message.  To satisfy
    // that implementation of CBounceWnd::OnColor, we call
    // GetCurrentMessage() and forward the wParam in the user-defined
    // WM_USER_ONCMDMSG message.  Alternatively, we could have
    // called GetMessageMsg and passed the wParam as an additional
    // member of the COnCmdMsg structure.

    return pBounceWnd->SendMessage(WM_USER_ONCMDMSG,
        GetCurrentMessage()->wParam, (LPARAM)&oncmdmsg);
}

BOOL CBounceMDIChildWnd::DestroyWindow()
{
    OnPrepareToClose();

    return CMDIChildWnd::DestroyWindow();
}

LRESULT CBounceMDIChildWnd::OnPrepareToClose(WPARAM, LPARAM)
{
    // Wait for the bounce thread to auto-destroy its CWinThread object
    // before continuing.  This avoids a possible false memory leak
    // detection in debug mode when exiting the application.  The false
    // memory leak might be reported if the main application thread
    // terminates sooner than the bounce thread auto-destroys its own
    // CWinThread object.  See also comments for CBounceWnd::OnNcDestroy.

    CWnd* pBounceWnd = (CBounceWnd*)GetDlgItem(IDC_BOUNCE_WND);
    pBounceWnd->SendMessage(WM_USER_PREPARE_TO_CLOSE);

    WaitForSingleObject(CBounceThread::m_hEventBounceThreadKilled, INFINITE);

    return 0;
}

/////////////////////////////////////////////////////////////////////////////
// CBounceWnd

BEGIN_MESSAGE_MAP(CBounceWnd, CWnd)
    //{{AFX_MSG_MAP(CBounceWnd)
    ON_WM_CREATE()
    ON_WM_SIZE()
    ON_WM_TIMER()
    ON_UPDATE_COMMAND_UI(IDM_RED, OnUpdateColor)
    ON_COMMAND(IDM_BLACK, OnColor)
    ON_COMMAND(IDM_CUSTOM, OnCustomColor)
    ON_UPDATE_COMMAND_UI(IDM_SLOW, OnUpdateSlow)
    ON_COMMAND(IDM_SLOW, OnSlow)
    ON_UPDATE_COMMAND_UI(IDM_FAST, OnUpdateFast)
    ON_COMMAND(IDM_FAST, OnFast)
    ON_WM_LBUTTONDOWN()
    ON_COMMAND(IDM_RED, OnColor)
    ON_COMMAND(IDM_GREEN, OnColor)
    ON_COMMAND(IDM_BLUE, OnColor)
    ON_COMMAND(IDM_WHITE, OnColor)
    ON_UPDATE_COMMAND_UI(IDM_WHITE, OnUpdateColor)
    ON_UPDATE_COMMAND_UI(IDM_GREEN, OnUpdateColor)
    ON_UPDATE_COMMAND_UI(IDM_CUSTOM, OnUpdateColor)
    ON_UPDATE_COMMAND_UI(IDM_BLUE, OnUpdateColor)
    ON_UPDATE_COMMAND_UI(IDM_BLACK, OnUpdateColor)
    ON_WM_DESTROY()
    //}}AFX_MSG_MAP
    ON_MESSAGE(WM_USER_ONCMDMSG, OnDelegatedCmdMsg)
    ON_MESSAGE(WM_USER_PREPARE_TO_CLOSE, OnPrepareToClose)
END_MESSAGE_MAP()

IMPLEMENT_DYNAMIC(CBounceWnd, CWnd)

/////////////////////////////////////////////////////////////////////////////
// CBounceWnd creation

BOOL CBounceWnd::Create(LPCTSTR szTitle, LONG style, const RECT& rect, CWnd* parent)
{
    // Register a custom WndClass and create a window.
    // This must be done because CBounceWnd has a custom cursor, and
    //  no icon.
    LPCTSTR lpszBounceClass =
        AfxRegisterWndClass(CS_HREDRAW | CS_VREDRAW,
            LoadCursor(NULL, IDC_UPARROW),
            (HBRUSH)(COLOR_WINDOW+1),
            NULL);

    return CWnd::Create(lpszBounceClass, szTitle, style, rect, parent,
        IDC_BOUNCE_WND);
}

CBounceWnd::CBounceWnd()
{
    m_nIDColor = IDM_BLACK;
    m_clrBall = RGB(0,0,0);
    m_bFastSpeed = FALSE;
}

void CBounceWnd::OnDestroy()
{
    // The following code forces a condition where the exiting application will
    // report a memory leak of the bounce CWinThread object if the application
    // does not wait for the bounce thread to auto-destroy its CWinThread object.
    // See also CMDIChildBounceWnd::OnNcDestroy.

#ifdef _DEBUG
    TRACE0("This is an intentional 1-second delay in terminating the bounce thread\n");
    Sleep(1000);
#endif
    CWnd::OnDestroy();
}

// Set up the ball parameters and start a timer.
int CBounceWnd::OnCreate(LPCREATESTRUCT /* p */)
{
    if (!SetTimer(1, 100 /*start slow*/, NULL))
    {
        MessageBox(_T("Not enough timers available for this window."),
                _T("MDI:Bounce"), MB_ICONEXCLAMATION | MB_OK);

        // signal creation failure...
        return -1;
    }

    CDC* pDC = GetDC();
    m_ptPixel.x = pDC->GetDeviceCaps(ASPECTX);
    m_ptPixel.y = pDC->GetDeviceCaps(ASPECTY);
    ReleaseDC(pDC);

    // Note that we could call MakeNewBall here (which should be called
    // whenever the ball's speed, color or size has been changed), but the
    // OnSize member function is always called after the OnCreate. Since
    // the OnSize member has to call MakeNewBall anyway, we don't here.

    return 0;
}

// MakeNewBall:
// Whenever a parameter changes which would affect the speed or appearance
// of the ball, call this to regenerate the ball bitmap.
//
void CBounceWnd::MakeNewBall()
{
    m_sizeTotal.cx = (m_sizeRadius.cx + ABS(m_sizeMove.cx)) << 1;
    m_sizeTotal.cy = (m_sizeRadius.cy + ABS(m_sizeMove.cy)) << 1;

    if (m_bmBall.m_hObject != NULL)
        m_bmBall.DeleteObject();        // get rid of old bitmap

    CClientDC dc(this);
    CDC dcMem;
    dcMem.CreateCompatibleDC(&dc);

    m_bmBall.CreateCompatibleBitmap(&dc, m_sizeTotal.cx, m_sizeTotal.cy);
    ASSERT(m_bmBall.m_hObject != NULL);

    CBitmap* pOldBitmap = dcMem.SelectObject(&m_bmBall);

    // draw a rectangle in the background (window) color
    CRect rect(0, 0, m_sizeTotal.cx, m_sizeTotal.cy);
    CBrush brBackground(::GetSysColor(COLOR_WINDOW));
    dcMem.FillRect(rect, &brBackground);

    CBrush brCross(HS_DIAGCROSS, 0L);
    CBrush* pOldBrush = dcMem.SelectObject(&brCross);

    dcMem.SetBkColor(m_clrBall);
    dcMem.Ellipse(ABS(m_sizeMove.cx), ABS(m_sizeMove.cy),
        m_sizeTotal.cx - ABS(m_sizeMove.cx),
        m_sizeTotal.cy - ABS(m_sizeMove.cy));

    dcMem.SelectObject(pOldBrush);
    dcMem.SelectObject(pOldBitmap);
    dcMem.DeleteDC();
}

// The ball's size and displacement change according to the window size.
void CBounceWnd::OnSize(UINT nType, int cx, int cy)
{
    LONG lScale;

    m_ptCenter.x = cx >> 1;
    m_ptCenter.y = cy >> 1;
    m_ptCenter.x += cx >> 3; // make the ball a little off-center

    lScale = min((LONG)cx * m_ptPixel.x,
        (LONG)cy * m_ptPixel.y) >> 4;
    m_sizeRadius.cx = (int)(lScale / m_ptPixel.x);
    m_sizeRadius.cy = (int)(lScale / m_ptPixel.y);
    m_sizeMove.cx = max(1, m_sizeRadius.cy >> 2);
    m_sizeMove.cy = max(1, m_sizeRadius.cy >> 2);

    MakeNewBall();

    CWnd::OnSize(nType, cx, cy);
}

/////////////////////////////////////////////////////////////////////////////
// CBounceWnd commands

LRESULT CBounceWnd::OnDelegatedCmdMsg(WPARAM, LPARAM lParam)
{
    COnCmdMsg* pOnCmdMsg = (COnCmdMsg*)lParam;
    return CWnd::OnCmdMsg(pOnCmdMsg->m_nID, pOnCmdMsg->m_nCode, pOnCmdMsg->m_pExtra,
            pOnCmdMsg->m_pHandlerInfo);
}

LRESULT CBounceWnd::OnPrepareToClose(WPARAM, LPARAM)
{
    DestroyWindow();
    return 0;
}

void CBounceWnd::OnUpdateColor(CCmdUI* pCmdUI)
{
    pCmdUI->SetCheck(pCmdUI->m_nID == m_nIDColor);
}

void CBounceWnd::OnColor()
{
    m_nIDColor = LOWORD(GetCurrentMessage()->wParam);
    m_clrBall = colorArray[m_nIDColor - IDM_BLACK];

    // Force the client area text to be repainted in the new color
    MakeNewBall();
    Invalidate();
}

void CBounceWnd::OnCustomColor()
{
    CColorDialog dlgColor(m_clrBall);
    if (dlgColor.DoModal() == IDOK)
    {
        m_clrBall = dlgColor.GetColor();
        m_nIDColor = IDM_CUSTOM;
        MakeNewBall();
        Invalidate();
    }
}

// Change the ball's speed
void CBounceWnd::ChangeSpeed()
{
    // re-create the timer
    KillTimer(1);
    if (!SetTimer(1, m_bFastSpeed ? 0 : 100, NULL))
    {
        MessageBox(_T("Not enough timers available for this window."),
                _T("MDI:Bounce"), MB_ICONEXCLAMATION | MB_OK);
        DestroyWindow();
    }
}

// Animate the ball.
void CBounceWnd::OnTimer(UINT /* wParam */)
{
    if (m_bmBall.m_hObject == NULL)
        return;     // no bitmap for the ball

    CRect rcClient;
    GetClientRect(rcClient);

    CClientDC dc(this);
    CBitmap* pbmOld = NULL;

    CDC dcMem;
    dcMem.CreateCompatibleDC(&dc);
    pbmOld = dcMem.SelectObject(&m_bmBall);

    dc.BitBlt(m_ptCenter.x - m_sizeTotal.cx / 2,
            m_ptCenter.y - m_sizeTotal.cy / 2,
            m_sizeTotal.cx, m_sizeTotal.cy,
            &dcMem, 0, 0, SRCCOPY);

    m_ptCenter += m_sizeMove;

    if ((m_ptCenter.x + m_sizeRadius.cx >= rcClient.right) ||
        (m_ptCenter.x - m_sizeRadius.cx <= 0))
    {
        m_sizeMove.cx = -m_sizeMove.cx;
    }

    if ((m_ptCenter.y + m_sizeRadius.cy >= rcClient.bottom) ||
        (m_ptCenter.y - m_sizeRadius.cy <= 0))
    {
        m_sizeMove.cy = -m_sizeMove.cy;
    }

    dcMem.SelectObject(pbmOld);
    dcMem.DeleteDC();
}

void CBounceWnd::OnUpdateSlow(CCmdUI* pCmdUI)
{
    pCmdUI->SetCheck(!m_bFastSpeed);
}

void CBounceWnd::OnSlow()
{
    m_bFastSpeed = FALSE;
    ChangeSpeed();
}

void CBounceWnd::OnUpdateFast(CCmdUI* pCmdUI)
{
    pCmdUI->SetCheck(m_bFastSpeed);
}

void CBounceWnd::OnFast()
{
    m_bFastSpeed = TRUE;
    ChangeSpeed();
}

void CBounceMDIChildWnd::OnSize(UINT nType, int cx, int cy)
{
    CMDIChildWnd::OnSize(nType, cx, cy);

    CWnd* pBounceWnd = GetDlgItem(IDC_BOUNCE_WND);
    if (pBounceWnd == NULL)
        return; // child CBounceWnd not created yet

    CRect rect;
    GetClientRect(&rect);
    pBounceWnd->SetWindowPos(NULL, 0, 0, rect.Width(), rect.Height(),
        SWP_NOACTIVATE | SWP_NOMOVE | SWP_NOZORDER);
}

void CBounceWnd::OnLButtonDown(UINT, CPoint point)
{
    Invalidate();

    CRect rcClient;
    GetClientRect(rcClient);

    point.x = min(point.x, rcClient.right - 2*m_sizeRadius.cx);
    point.x = max(point.x, 2*m_sizeRadius.cx);
    point.y = min(point.y, rcClient.bottom - 2*m_sizeRadius.cx);
    point.y = max(point.y, 2*m_sizeRadius.cy);

    m_ptCenter = point;
}