c++ - MFC 应用程序 : animating graphics cause program to not respond

Question

我目前正在尝试创建一个 MFC 程序，该程序显示一种涉及对象的动画，对象的位置以图形方式转换为小板上的矩形、椭圆等位置。这是一个 32 位程序。

我的想法是，当用户按下按钮时，他会以特定的时间速率看到模拟。但是，我的代码使其仅在有人不断点击按钮以推进模拟时运行。

当我用另一个按钮做同样的事情时，图形动画通常很流畅。但是，我的窗口屏幕上最终出现了一个 (Not Responding) 提示(在非特定时间)，导致图形卡住，直到模拟完成。

如何防止图形窗口卡住？

相关代码:

void Csmart_parking_guiDlg::OnPaint()
{
    if (IsIconic())
    {
        CPaintDC dc(this); // device context for painting

        SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

        // Center icon in client rectangle
        int cxIcon = GetSystemMetrics(SM_CXICON);
        int cyIcon = GetSystemMetrics(SM_CYICON);
        CRect rect;
        GetClientRect(&rect);
        int x = (rect.Width() - cxIcon + 1) / 2;
        int y = (rect.Height() - cyIcon + 1) / 2;

        // Draw the icon
        dc.DrawIcon(x, y, m_hIcon);
    }
    else
    {
        CDialogEx::OnPaint();
    }
    DrawGrid();
}


void Csmart_parking_guiDlg::DrawGrid() {
    CRect gridBase;
    gridDrawSurface->GetWindowRect(&gridBase);
    this->ScreenToClient(&gridBase);
    CPoint bottomRight = gridBase.TopLeft();
    int rectSize = 400;
    bottomRight += CPoint(rectSize, rectSize);
    gridBase.BottomRight() = bottomRight;
    gridBase.NormalizeRect();
    gridDraw->Rectangle(gridBase);
    int baseRectWidth = gridBase.Width();
    int baseRectHeight = gridBase.Height();
    double proportion = (baseRectWidth / world->getGridSize());
    // Draw destinations. Set boolean to check if all are drawn yet
        CBrush brushDest(RGB(165, 42, 42));
        gridBrush = gridDraw->SelectObject(&brushDest);
        CPen penBlack;
        penBlack.CreatePen(PS_SOLID, 1, RGB(0, 0, 0));
        gridPen = gridDraw->SelectObject(&penBlack);
        vector <Location> destLoc = world->getDestLocations();
        int xCenter;
        int yCenter;
        for (size_t ii = 0; ii < destLoc.size(); ii++) { // draw brown circle
            xCenter = (int)round(gridBase.TopLeft().x + destLoc[ii].x*proportion);
            yCenter = (int)round(gridBase.TopLeft().y + destLoc[ii].y*proportion);
            gridDraw->Rectangle(xCenter - 4, yCenter-4, xCenter+4, yCenter+4);
        }
        gridDraw->SelectObject(gridBrush);
        destDrawn = true;
    // Draw lots.
        CBrush brushLot(RGB(35, 62, 148));
        gridDraw->SetTextColor(RGB(35, 62, 148));
        // gridDraw->SetBkMode(TRANSPARENT);
        gridBrush = gridDraw->SelectObject(&brushLot);
        vector<Location> lotLoc = world->getLotLocations();
        vector<int> lotSpots;
        vector<Lot *> allLots = world->getAllLots();
        for (size_t ii = 0; ii < allLots.size(); ii++) {
            lotSpots.push_back(allLots[ii]->getOpenSpots());
        }
        for (size_t ii = 0; ii < lotLoc.size(); ii++) { // draw blue circle and number
            xCenter = (int)round(gridBase.TopLeft().x + lotLoc[ii].x*proportion);
            yCenter = (int)round(gridBase.TopLeft().y + lotLoc[ii].y*proportion);
            gridDraw->Ellipse(xCenter-3, yCenter-3, xCenter+3, yCenter+3);
            CString echoNum;
            echoNum.Format(_T("%d"), lotSpots[ii]);
            gridDraw->TextOutW(xCenter + 4, yCenter + 1, echoNum);
        }
        lotDrawn = true;
        gridDraw->SelectObject(gridBrush);
        gridDraw->SelectObject(gridPen);
    // Draw drivers
    vector<Location> driverLoc = world->getDriverLocations(); // get all drivers currently visible on screen
    for (size_t ii = 0; ii < driverLoc.size(); ii++) { // draw red dot
        xCenter = (int)round(gridBase.TopLeft().x + driverLoc[ii].x*proportion);
        yCenter = (int)round(gridBase.TopLeft().y + driverLoc[ii].y*proportion);
        gridDraw->Rectangle(xCenter - 1, yCenter - 1, xCenter + 1, yCenter + 1);
    }
}

void Csmart_parking_guiDlg::OnBnClickedBSimend() // On clicking, simulation jumps to the very end.
{
    while (!world->simulationOver[world->getCurrentIteration()]) {
        run_simulation(*world);
        m_TimeDisplay = world->getTime(); // double
        m_EchoTime.Format(_T("Time: %g"), m_TimeDisplay);
        if (!world->simulationOver[world->getCurrentIteration()]) oss << world->getCurrentEvent();
        CString c_status(oss.str().c_str());
        m_EchoStatus = c_status;
        UpdateData(FALSE);
        OnPaint();
        GetDlgItem(IDC_ST_STATUS)->RedrawWindow();
        pEdit->LineScroll(pEdit->GetLineCount());
        // theApp.PumpMessage(); // this works but it makes it way too slow
        // Sleep(50); // program stops responding at times with a sleep message
    }
}

Answer 1

您可以(并且应该)摆脱 while 循环，只需调用 SetTimer 即可开始模拟。然后在每次调用 WM_TIMER 消息处理程序时执行模拟的一个步骤。你永远不应该自己调用 OnPaint。您的计时器可以调用 Invalidate 使 Windows 调用 OnPaint。