Ｗｉｎ３２ＡＰＩでタイマーを作る

/*
*  タイマー
*/

#include <windows.h>
#include <stdio.h>

#define ID_B1      1000
#define ID_EDIT1   2000
#define ID_MYTIMER 3000

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);

int APIENTRY WinMain(
  HINSTANCE hInstance,
  HINSTANCE hPreInstance,
  LPSTR cmdLine,
  int cmdShow)
{
  WNDCLASS wd;

  char *wdName = "nmtimer00";

  if(!hPreInstance){
    wd.style = CS_HREDRAW | CS_VREDRAW;  //幅、高さの変化に対し再描画する
    wd.lpfnWndProc = (WNDPROC)WndProc;
    wd.cbClsExtra = 0;
    wd.cbWndExtra = 0;
    wd.hInstance = hInstance;
    wd.hIcon = NULL;
    wd.hCursor = LoadCursor(NULL, IDC_ARROW);
    wd.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wd.lpszMenuName = NULL;
    wd.lpszClassName = wdName;

    if(!RegisterClass(&wd)){
      return FALSE;
    }
  }

  RECT rect;

  rect.left = 0;
  rect.top = 0;
  rect.right = 300;
  rect.bottom = 200;

  AdjustWindowRect(&rect, WS_OVERLAPPEDWINDOW, FALSE);

  HWND form00 = CreateWindowEx(
    NULL,
    wdName,
    "nmTimer v1.00",
    WS_OVERLAPPEDWINDOW,
    CW_USEDEFAULT,
    CW_USEDEFAULT,
    rect.right - rect.left,
    rect.bottom - rect.top,
    NULL,
    NULL,
    hInstance,
    NULL);

  ShowWindow(form00, cmdShow);
  UpdateWindow(form00);

  MSG msg;
  while(GetMessage(&msg, NULL, NULL, NULL)){
    TranslateMessage(&msg);
    DispatchMessage(&msg);
  }
  return msg.wParam;
}

// ウィンドウプロシージャ
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam){
  // 0:停止 1:起動
  static int state = 0;
  // カウント 秒
  static int count = 0;

  static HWND hButton1;
  static HWND hEdit1;
  static HFONT hFont;

  HINSTANCE hInst;
  hInst = (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE);

  switch(message){
    case WM_CREATE:
      {
        hButton1 = CreateWindow("BUTTON", "START", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 0, 0, 0, 0, hwnd, (HMENU)ID_B1, hInst, NULL);
        hEdit1 = CreateWindow("EDIT", "3:00", WS_CHILD | WS_VISIBLE, 0, 0, 0, 0, hwnd, (HMENU)ID_EDIT1, hInst, NULL);
      }
      break;
    case WM_SIZE:
      {
        RECT rect;
        GetClientRect(hwnd, &rect);
        int h1 = rect.bottom / 3 * 2;
        int h2 = rect.bottom - h1;
        hFont = CreateFont(h1,0,0,0,FW_REGULAR,FALSE,FALSE,FALSE,SHIFTJIS_CHARSET,OUT_DEFAULT_PRECIS,CLIP_DEFAULT_PRECIS,DEFAULT_QUALITY,FIXED_PITCH | FF_MODERN,(LPCTSTR)"ＭＳ ゴシック");
        MoveWindow(hEdit1
          ,rect.left
          ,rect.top
          ,rect.right
          ,h1
          ,TRUE);
        MoveWindow(hButton1
          ,rect.left
          ,h1
          ,rect.right
          ,h2
          ,TRUE);
        SetWindowPos(hwnd, HWND_TOPMOST, 0, 0, 0, 0, (SWP_SHOWWINDOW | SWP_NOMOVE | SWP_NOSIZE));
      }
      break;
    case WM_TIMER:
      {
        if(count > 0){
          count--;
        }
        if(count == 0){
          MessageBeep(-1);
          state = 0;
          SetWindowText(hEdit1, (LPTSTR)"3:00");
          ShowWindow(hEdit1, TRUE);
          KillTimer(hwnd, ID_MYTIMER);
          SetWindowText(hButton1, (LPCTSTR)"START");
        }
        InvalidateRect(hwnd, NULL, FALSE);
      }
      break;
    case WM_PAINT:
      {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd, &ps);
        if(state == 1){
          RECT rect;
          GetClientRect(hwnd, &rect);
          HPEN hPen = CreatePen(PS_SOLID, 2, RGB(255, 255, 255));
          HPEN hOldPen = (HPEN)SelectObject(hdc, (HPEN)hPen);
          SelectObject(hdc, GetStockObject(WHITE_BRUSH));
          Rectangle(hdc, 0, 0, rect.right, rect.bottom / 3 * 2);
          SelectObject(hdc, hOldPen);
          DeleteObject(hPen);
          char buf[256];
          sprintf(buf, "%d:%02d", count / 60, count % 60);
          SelectObject(hdc, hFont);
          TextOut(hdc, 0, 0, buf, strlen(buf));
        }
        EndPaint(hwnd, &ps);
      }
      break;
    case WM_COMMAND:
      switch(LOWORD(wParam)){
        case ID_B1:
          {
            char buf[256];
            GetWindowText(hEdit1, (LPTSTR)buf, 64);

            int num1, num2;
            sscanf(buf, "%d:%d", &num1, &num2);
            int res = num1 * 60 + num2;

            if(state == 0){
              if(res >= 0){
                state = 1;
                count = res;
                ShowWindow(hEdit1, FALSE);
                SetTimer(hwnd, ID_MYTIMER, 1000, NULL);
                SetWindowText(hButton1, (LPCTSTR)"STOP");
              }
            }
            else{
              state = 0;
              char buf[256];
              sprintf(buf, "%d:%02d", count / 60, count % 60);
              SetWindowText(hEdit1, (LPTSTR)buf);
              ShowWindow(hEdit1, TRUE);
              KillTimer(hwnd, ID_MYTIMER);
              SetWindowText(hButton1, (LPCTSTR)"START");
            }
          }
          break;
        default:
          return(DefWindowProc(hwnd, message, wParam, lParam));
      }
      break;
    case WM_DESTROY:
      PostQuitMessage(0);
      break;
    default:
      return DefWindowProc(hwnd, message, wParam, lParam);
  }
  return NULL;
}