第七章 鼠标（CHECKER4）

/*---------------------------------------------
CHECKER4.C -- Mouse Hit-Test Demo Program No.4
              (c) Charles Petzold, 1998
--------------------------------------------*/

#include <Windows.h>

#define DIVISIONS 5

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

int idFocus = 0;
TCHAR szChildClass[] = TEXT("Checker4_Child");

int WINAPI WinMain( __in HINSTANCE hInstance
                    , __in_opt HINSTANCE hPrevInstance
                    , __in LPSTR lpCmdLine
                    , __in int nShowCmd )
{
    static TCHAR szAppName[] = TEXT("Checker4");
    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;
    }

    wndclass.lpfnWndProc = ChildWndProc;
    wndclass.cbWndExtra = sizeof(long);
    wndclass.hIcon = NULL;
    wndclass.lpszClassName = szChildClass;

    RegisterClass(&wndclass);

    hwnd = CreateWindow(szAppName, TEXT("Checker4 Mouse Hit-Test Demo")
        , 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;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static HWND hwndChild[DIVISIONS][DIVISIONS];
    int cxBlock, cyBlock, x, y;

    switch (message)
    {
    case WM_CREATE:
        for (x = 0; x != DIVISIONS; ++x)
            for (y = 0; y != DIVISIONS; ++y)
            {
                hwndChild[x][y] = CreateWindow(szChildClass, NULL
                    , WS_CHILDWINDOW | WS_VISIBLE
                    , 0, 0, 0, 0
                    , hwnd, (HMENU)(y << 8 | x)
                    , (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE), NULL);
            }
        return 0;

    case WM_SIZE:
        cxBlock = LOWORD(lParam) / DIVISIONS;
        cyBlock = HIWORD(lParam) / DIVISIONS;

        for (x = 0; x != DIVISIONS; ++x)
            for (y = 0; y != DIVISIONS; ++y)
            {
                MoveWindow(hwndChild[x][y]
                    , x * cxBlock, y * cyBlock
                    , cxBlock, cyBlock, TRUE);
            }
        return 0;

    case WM_LBUTTONDOWN:
        MessageBeep(0);
        return 0;

        //on set-focus message, set focus to child window
    case WM_SETFOCUS:
        SetFocus(GetDlgItem(hwnd, idFocus));
        return 0;

        //on key-down message, possibly change the focus window
    case WM_KEYDOWN:
        x = idFocus & 0xff;
        y = idFocus >> 8;

        switch (wParam)
        {
        case VK_UP:
            --y;
            break;

        case VK_DOWN:
            ++y;
            break;

        case VK_LEFT:
            --x;
            break;

        case VK_RIGHT:
            ++x;
            break;

        case VK_HOME:
            x = y = 0;
            break;

        case VK_END:
            x = y = DIVISIONS - 1;
            break;

        default:
            return 0;
        }

        x = (x + DIVISIONS) % DIVISIONS;
        y = (y + DIVISIONS) % DIVISIONS;

        idFocus = y << 8 | x;
        SetFocus(GetDlgItem(hwnd, idFocus));
        return 0;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }

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

LRESULT CALLBACK ChildWndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    RECT rect;

    switch (message)
    {
    case WM_CREATE:
        SetWindowLong(hwnd, DWL_MSGRESULT, 0);    // on/off flag
        return 0;

    case WM_KEYDOWN:
        //send most key press to the parent window
        if (wParam != VK_RETURN && wParam != VK_SPACE)
        {
            SendMessage(GetParent(hwnd), message, wParam, lParam);
            return 0;
        }

        //for Return and Space, fall through to toggle the square
    case WM_LBUTTONDOWN:
        SetWindowLong(hwnd, DWL_MSGRESULT, 1 ^ GetWindowLong(hwnd, DWL_MSGRESULT));
        SetFocus(hwnd);
        InvalidateRect(hwnd, &rect, FALSE);
        return 0;

        //for focus message, invalidate the window for repaint
    case WM_SETFOCUS:
        idFocus = GetWindowLong(hwnd, GWL_ID);

        //fall through
    case WM_KILLFOCUS:
        InvalidateRect(hwnd, NULL, TRUE);
        return 0;

    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        
        GetClientRect(hwnd, &rect);
        Rectangle(hdc, 0, 0, rect.right, rect.bottom);

        //draw the "x" mark
        if (GetWindowLong(hwnd, DWL_MSGRESULT))
        {
            MoveToEx(hdc, 0, 0, NULL);
            LineTo(hdc, rect.right, rect.bottom);
            MoveToEx(hdc, 0, rect.bottom, NULL);
            LineTo(hdc, rect.right, 0);
        }

        //draw the "focus" rectangle
        if (hwnd == GetFocus())
        {
            rect.left += rect.right / 10;
            rect.right -= rect.left;
            rect.top += rect.bottom / 10;
            rect.bottom -= rect.top;

            SelectObject(hdc, GetStockObject(NULL_BRUSH));
            SelectObject(hdc, CreatePen(PS_DASH, 0, 0));
            Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);
            DeleteObject(SelectObject(hdc, GetStockObject(BLACK_PEN)));
        }

        EndPaint(hwnd, &ps);
        return 0;
    }

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