練手–用Windows SDK寫一個簡易時鐘

網上的高手都說要學編程一定不能不學底層，俺也學學。

#include <windows.h>
#include <math.h>

#define PI 3.1415926535
#define IDT_TM1 1
struct TIME_POINT{
 int x;
 int y;
 char s[2];
};//這是時鐘盤面上的時刻點結構

LRESULT CALLBACK WindProc(HWND,UINT,WPARAM,LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd );
bool init_WndClass(HINSTANCE hInstance);
bool init_WINDOW(HINSTANCE hInstance,int nShowCmd);

HWND _hwnd;
WNDCLASS _windclass;
MSG _msg;
TCHAR _clsname[]="Sunjoy的類";

bool init_WndClass(HINSTANCE hInstance){
 
 _windclass.style        = CS_HREDRAW | CS_VREDRAW ;
 _windclass.hInstance=hInstance;
 _windclass.lpfnWndProc=WindProc;
 _windclass.cbClsExtra=0;
 _windclass.cbWndExtra=0;
 _windclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
 _windclass.hCursor=LoadCursor(NULL,IDC_ARROW);
 _windclass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
 _windclass.lpszClassName=_clsname;
 _windclass.lpszMenuName=NULL;
 
 return (RegisterClass(&_windclass)!=NULL);
}

bool init_WINDOW(HINSTANCE hInstance,int nShowCmd){
  _hwnd=CreateWindow(_clsname,
  "簡易時鐘",
  WS_OVERLAPPEDWINDOW,
  CW_USEDEFAULT,
  CW_USEDEFAULT,
  450,
  450,
  NULL,
  NULL,
  hInstance,
  NULL);
 ShowWindow(_hwnd,nShowCmd);
 return (UpdateWindow(_hwnd)!=NULL);
}

int WINAPI WinMain(HINSTANCE hInstance,
       HINSTANCE hPrevInstance,
       LPSTR lpCmdLine,
       int nShowCmd )
{
 if(!init_WndClass(hInstance) || !init_WINDOW(hInstance,nShowCmd)){
  MessageBox(NULL,"建立視窗出錯",NULL,NULL);
 }

 
 
 while(GetMessage(&_msg,NULL,0,0)){
  TranslateMessage ( &_msg);
  DispatchMessage(&_msg);
 }
 return _msg.wParam;
}

LRESULT CALLBACK WindProc(HWND _hwnd,
        UINT _message,
        WPARAM _wparam,
        LPARAM _lparasm)
{
 HDC hdc;
 HPEN hpen;
 HBRUSH hbrush;
 PAINTSTRUCT ps;
 int cx=220; //圓心x座標
 int cy=215; //圓心y座標
 int r=200;  //圓的半徑
 TIME_POINT tmp[12]; //時刻
 int i=0;
 SYSTEMTIME systm; //系統時間
 for(i=0;i<12;i++){
  tmp[i].x=(int)(cx+(r-10)*sin(i*PI/6));
  tmp[i].y=(int)(cy-(r-10)*cos(i*PI/6));
  wsprintf(tmp[i].s,"%d",i);
 }
 strcpy(tmp[0].s,"12"); //初始化時鐘盤面座標
 
 switch(_message){
 case WM_CREATE:
  SetTimer (_hwnd, IDT_TM1, 1000, NULL) ;
  return 0;
 case WM_PAINT:
  
  hdc=BeginPaint(_hwnd,&ps);
  hpen=CreatePen(PS_SOLID,2,RGB(0,0,0));
  SelectObject(hdc,hpen);
  MoveToEx(hdc,cx,cy,NULL);
  Arc(hdc,cx-r,cy-r,r+cx,r+cy,cx+r,cy,cx+r,cy); //畫時鐘圓盤
  for(i=0;i<12;i++){
   TextOut(hdc,tmp[i].x-5,tmp[i].y-8,tmp[i].s,strlen(tmp[i].s));
  }//初始化時鐘盤面
  DeleteObject(hpen);
  
  //刷白
  hbrush=(HBRUSH)GetStockObject(WHITE_BRUSH);
  hpen=CreatePen(PS_SOLID,1,RGB(255,255,255));
  SelectObject(hdc,hbrush);
  SelectObject(hdc,hpen);
  Pie(hdc,cx-r+19,cy-r+19,cx+r-19,cy+r-19,cx+r-19,cy,cx+r-19,cy);
  MoveToEx(hdc,cx,cy,NULL);
  
  DeleteObject(hbrush);
  DeleteObject(hpen);

  //擷取本地時間 
  GetLocalTime(&systm);
  //畫秒針
  hpen=CreatePen(PS_SOLID,2,RGB(0,0,255));
  SelectObject(hdc,hpen);
  MoveToEx(hdc,cx,cy,NULL);
  LineTo(hdc,(int)(cx+(r-20)*sin(systm.wSecond*PI/30)),(int)(cy-(r-20)*cos(systm.wSecond*PI/30)));
  DeleteObject(hpen);
  
  //畫分針
  hpen=CreatePen(PS_SOLID,4,RGB(0,255,0));
  SelectObject(hdc,hpen);
  MoveToEx(hdc,cx,cy,NULL);
  LineTo(hdc,(int)(cx+(r-50)*sin(systm.wMinute*PI/30)),(int)(cy-(r-50)*cos(systm.wMinute*PI/30)));
  DeleteObject(hpen);
  
  //畫時針
  
  hpen=CreatePen(PS_SOLID,8,RGB(255,0,0));
  SelectObject(hdc,hpen);
  MoveToEx(hdc,cx,cy,NULL);
  LineTo(hdc,(int)(cx+(r-100)*sin(systm.wHour%12*PI/6)),(int)(cy-(r-100)*cos(systm.wHour%12*PI/6)));
  DeleteObject(hpen);

  EndPaint(_hwnd,&ps);
  
  return 0;
 case WM_TIMER:
  InvalidateRect(_hwnd,NULL,NULL); //計時器到時，重新整理無效區
  return 0;
 case WM_DESTROY:
  PostQuitMessage(0);
  return 0;
 }

 return DefWindowProc(_hwnd,_message,_wparam,_lparasm);

}