第八章 计时器（DIGCLOCK）

/*--------------------------------------
DIGCLOCK.C -- Digital Clock
              (c) Charles Petzold, 1998
--------------------------------------*/

#include <Windows.h>

#define ID_TIMER 1

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain( __in HINSTANCE hInstance
                    , __in_opt HINSTANCE hPrevInstance
                    , __in LPSTR lpCmdLine
                    , __in int nShowCmd )
{
    static TCHAR szAppName[] = TEXT("DigClock");
    HWND hwnd;
    MSG msg;
    WNDCLASS wndclass;

    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;

    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("Program requires Windows NT!")
            , szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName, TEXT("Digital Clock")
        , WS_OVERLAPPEDWINDOW
        , CW_USEDEFAULT, CW_USEDEFAULT
        , CW_USEDEFAULT, CW_USEDEFAULT
        , NULL, NULL, hInstance, NULL);

    ShowWindow(hwnd, nShowCmd);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return msg.wParam;
}

void DisplayDigit(HDC hdc, int iNumber)
{
    static BOOL fSevenSegment[10][7] = 
    {
        1, 1, 1, 0, 1, 1, 1,    //0
        0, 0, 1, 0, 0, 1, 0,    //1
        1, 0, 1, 1, 1, 0, 1,    //2
        1, 0, 1, 1, 0, 1, 1,    //3
        0, 1, 1, 1, 0, 1, 0,    //4
        1, 1, 0, 1, 0, 1, 1,    //5
        1, 1, 0, 1, 1, 1, 1,    //6
        1, 0, 1, 0, 0, 1, 0,    //7
        1, 1, 1, 1, 1, 1, 1,    //8
        1, 1, 1, 1, 0, 1, 1        //9
    };

    static POINT ptSegment[7][6] =
    {
        7, 6, 11, 2, 31, 2, 35, 6, 31, 10, 11, 10,
        6, 7, 10, 11, 10, 31, 6, 35, 2, 31, 2, 11,
        36, 7, 40, 11, 40, 31, 36, 35, 32, 31, 32, 11,
        7, 36, 11, 32, 31, 32, 35, 36, 31, 40, 11, 40,
        6, 37, 10, 41, 10, 61, 6, 65, 2, 61, 2, 41,
        36, 37, 40, 41, 40, 61, 36, 65, 32, 61, 32, 41,
        7, 66, 11, 62, 31, 62, 35, 66, 31, 70, 11, 70 

    };

    for (int iSeg(0); iSeg != 7; ++iSeg)
    {
        if (fSevenSegment[iNumber][iSeg])
            Polygon(hdc, ptSegment[iSeg], 6);
    }
}

void DisplayTwoDigits(HDC hdc, int iNumber, BOOL fSuppress)
{
    if (!fSuppress || (iNumber / 10 != 0))
        DisplayDigit(hdc, iNumber / 10);
    
    OffsetWindowOrgEx(hdc, -42, 0, NULL);
    DisplayDigit(hdc, iNumber % 10);
    OffsetWindowOrgEx(hdc, -42, 0, NULL);
}

void DisplayColon(HDC hdc)
{
    POINT ptColon[2][4] = { 2, 21, 6, 17, 10, 21, 6, 25,
                            2, 51, 6, 47, 10, 51, 6, 55 };
    
    Polygon(hdc, ptColon[0], 4);
    Polygon(hdc, ptColon[1], 4);

    OffsetWindowOrgEx(hdc, -12, 0, NULL);
}

void DisplayTime(HDC hdc, BOOL f24Hour, BOOL fSuppress)
{
    SYSTEMTIME st;

    GetLocalTime(&st);

    if (f24Hour)
        DisplayTwoDigits(hdc, st.wHour, fSuppress);
    else
        DisplayTwoDigits(hdc, (st.wHour %= 12) ? st.wHour : 12, fSuppress);

    DisplayColon(hdc);
    DisplayTwoDigits(hdc, st.wMinute, FALSE);
    DisplayColon(hdc);
    DisplayTwoDigits(hdc, st.wSecond, FALSE);
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static BOOL f24Hour, fSuppress;
    static HBRUSH hBrushRed;
    static int cxClient, cyClient;
    HDC hdc;
    PAINTSTRUCT ps;
    TCHAR szBuffer[2];

    switch (message)
    {
    case WM_CREATE:
        hBrushRed = CreateSolidBrush(RGB(255, 0, 0));
        SetTimer(hwnd, ID_TIMER, 1000, NULL);

        //fall through
    case WM_SETTINGCHANGE:
        GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_ITIME, szBuffer, 2);
        f24Hour = (szBuffer[0] == TEXT('1'));

        GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_ITLZERO, szBuffer, 2);
        fSuppress = (szBuffer[0] == TEXT('0'));

        InvalidateRect(hwnd, NULL, TRUE);
        return 0;

    case WM_SIZE:
        cxClient = LOWORD(lParam);
        cyClient = HIWORD(lParam);
        return 0;

    case WM_TIMER:
        InvalidateRect(hwnd, NULL, TRUE);
        return 0;

    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);

        SetMapMode(hdc, MM_ISOTROPIC);
        SetWindowExtEx(hdc, 276, 72, NULL);
        SetViewportExtEx(hdc, cxClient, cyClient, NULL);

        SetWindowOrgEx(hdc, 138, 36, NULL);
        SetViewportOrgEx(hdc, cxClient / 2, cyClient / 2, NULL);
        SelectObject(hdc, GetStockObject(NULL_PEN));
        SelectObject(hdc, hBrushRed);

        DisplayTime(hdc, f24Hour, fSuppress);

        EndPaint(hwnd, &ps);
        return 0;

    case WM_DESTROY:
        KillTimer(hwnd, ID_TIMER);
        DeleteObject(hBrushRed);
        PostQuitMessage(0);
        return 0;
    }

    return DefWindowProc(hwnd, message, wParam, lParam);
}