/*---------------------------------------------

 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 = ;

 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 = ;

     wndclass.cbWndExtra = ;

     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 ;

     }

     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, , ))

     {

         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 = ; x != DIVISIONS; ++x)

             for (y = ; y != DIVISIONS; ++y)

             {

                 hwndChild[x][y] = CreateWindow(szChildClass, NULL

                     , WS_CHILDWINDOW | WS_VISIBLE

                     , , , ,

                     , hwnd, (HMENU)(y <<  | x)

                     , (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE), NULL);

             }

         return ;

     case WM_SIZE:

         cxBlock = LOWORD(lParam) / DIVISIONS;

         cyBlock = HIWORD(lParam) / DIVISIONS;

         for (x = ; x != DIVISIONS; ++x)

             for (y = ; y != DIVISIONS; ++y)

             {

                 MoveWindow(hwndChild[x][y]

                     , x * cxBlock, y * cyBlock

                     , cxBlock, cyBlock, TRUE);

             }

         return ;

     case WM_LBUTTONDOWN:

         MessageBeep();

         return ;

         //on set-focus message, set focus to child window

     case WM_SETFOCUS:

         SetFocus(GetDlgItem(hwnd, idFocus));

         return ;

         //on key-down message, possibly change the focus window

     case WM_KEYDOWN:

         x = idFocus & 0xff;

         y = idFocus >> ;

         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 = ;

             break;

         case VK_END:

             x = y = DIVISIONS - ;

             break;

         default:

             return ;

         }

         x = (x + DIVISIONS) % DIVISIONS;

         y = (y + DIVISIONS) % DIVISIONS;

         idFocus = y <<  | x;

         SetFocus(GetDlgItem(hwnd, idFocus));

         return ;

     case WM_DESTROY:

         PostQuitMessage();

         return ;

     }

     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, );    // on/off flag

         return ;

     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 ;

         }

         //for Return and Space, fall through to toggle the square

     case WM_LBUTTONDOWN:

         SetWindowLong(hwnd, DWL_MSGRESULT,  ^ GetWindowLong(hwnd, DWL_MSGRESULT));

         SetFocus(hwnd);

         InvalidateRect(hwnd, &rect, FALSE);

         return ;

         //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 ;

     case WM_PAINT:

         hdc = BeginPaint(hwnd, &ps);

         GetClientRect(hwnd, &rect);

         Rectangle(hdc, , , rect.right, rect.bottom);

         //draw the "x" mark

         if (GetWindowLong(hwnd, DWL_MSGRESULT))

         {

             MoveToEx(hdc, , , NULL);

             LineTo(hdc, rect.right, rect.bottom);

             MoveToEx(hdc, , rect.bottom, NULL);

             LineTo(hdc, rect.right, );

         }

         //draw the "focus" rectangle

         if (hwnd == GetFocus())

         {

             rect.left += rect.right / ;

             rect.right -= rect.left;

             rect.top += rect.bottom / ;

             rect.bottom -= rect.top;

             SelectObject(hdc, GetStockObject(NULL_BRUSH));

             SelectObject(hdc, CreatePen(PS_DASH, , ));

             Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);

             DeleteObject(SelectObject(hdc, GetStockObject(BLACK_PEN)));

         }

         EndPaint(hwnd, &ps);

         return ;

     }

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

 }