计时器(3)机械时钟

获取当前时间

SYSTEMTIME st;GetSystemTime(&st);//是伦敦XX时间，跟北京时间相差8个时区GetLocaltime(&st)//获取的你电脑系统上显示的时间

LRESULT CALLBACK WindowProc(  HWND hwnd,      // handle to window  UINT uMsg,      // message identifier  WPARAM wParam,  // first message parameter  LPARAM lParam   // second message parameter){SYSTEMTIME st;HDC hdc;PAINTSTRUCT ps;TCHAR szBuffer[50];switch(uMsg){case WM_CREATE://GetSystemTime(&st);//获取的小时数跟北京的相差8个小时GetLocalTime(&st);wsprintf(szBuffer,TEXT("the time is %d H: %d m: %d s"),(int)st.wHour,st.wMinute,st.wSecond);MessageBox(NULL,szBuffer,TEXT("systemtime"),MB_ICONERROR);return 0;case WM_PAINT:return 0;case WM_DESTROY:PostQuitMessage(0);return 0;}return DefWindowProc(hwnd,uMsg,wParam,lParam);}

再看看SYSTEMTIME的结构吧

typedef struct _SYSTEMTIME {     WORD wYear;     WORD wMonth;     WORD wDayOfWeek;     WORD wDay;     WORD wHour;     WORD wMinute;     WORD wSecond;     WORD wMilliseconds; } SYSTEMTIME, *PSYSTEMTIME;

下面看看机械时钟，很酷喔

#include<windows.h>#include<windowsx.h>#include<math.h>#define ID_TIMER 1#define TOWPI (2*3.14159)LRESULT CALLBACK WindowProc(  HWND hwnd,      // handle to window  UINT uMsg,      // message identifier  WPARAM wParam,  // first message parameter  LPARAM lParam   // second message parameter);int WINAPI WinMain(  HINSTANCE hInstance,      // handle to current instance  HINSTANCE hPrevInstance,  // handle to previous instance  LPSTR lpCmdLine,          // command line  int nCmdShow              // show state){static TCHAR szAppName[]=TEXT("leidemingzi");HWND hwnd;MSG msg;WNDCLASS wndclass;wndclass.cbClsExtra=0;wndclass.cbWndExtra=0;wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);wndclass.hIcon=LoadIcon(NULL,IDI_ERROR);wndclass.hInstance=hInstance;wndclass.lpfnWndProc=WindowProc;wndclass.lpszClassName=szAppName;wndclass.lpszMenuName=NULL;wndclass.style=CS_HREDRAW|CS_VREDRAW;if(!RegisterClass(&wndclass)){MessageBox(NULL,TEXT("The program require window nt"),TEXT("this is tips"),MB_ICONERROR);return 0;}hwnd=CreateWindow(  szAppName,  // registered class name  TEXT("this is title"), // window name  WS_OVERLAPPEDWINDOW,        // window style  CW_USEDEFAULT,                // horizontal position of window  CW_USEDEFAULT,                // vertical position of window  CW_USEDEFAULT,           // window width  CW_USEDEFAULT,          // window height  NULL,      // handle to parent or owner window  NULL,          // menu handle or child identifier  hInstance,  // handle to application instance  NULL        // window-creation data);ShowWindow(hwnd,nCmdShow);UpdateWindow(hwnd);while(GetMessage(&msg,NULL,0,0)){TranslateMessage(&msg);DispatchMessage(&msg);}return msg.wParam;}void SetIsotropic(HDC hdc,int cxClient,int cyClient){SetMapMode(hdc,MM_ISOTROPIC);SetWindowExtEx(hdc,1000,1000,NULL);SetViewportExtEx(hdc,cxClient/2,-cyClient/2,NULL);SetViewportOrgEx(hdc,cxClient/2,cyClient/2,NULL);}void RotatePoint(POINT pt[],int iNum,int iAngle){int i;POINT ptTemp;for(i=0;i<iNum;++i){ptTemp.x=(int)(pt[i].x*cos(TOWPI*iAngle/360)+pt[i].y*sin(TOWPI*iAngle/360));ptTemp.y=(int)(pt[i].y*cos(TOWPI*iAngle/360)-pt[i].x*sin(TOWPI*iAngle/360));pt[i]=ptTemp;}}void DrawClock(HDC hdc){int iAngle;POINT pt[3];for(iAngle=0;iAngle<360;iAngle+=6){pt[0].x=0;pt[0].y=900;RotatePoint(pt,1,iAngle);pt[2].x=pt[2].y=iAngle%5?33:100;pt[0].x-=pt[2].x/2;pt[0].y-=pt[2].y/2;pt[1].x=pt[0].x+pt[2].x;pt[1].y=pt[0].y+pt[2].y;SelectObject(hdc,GetStockObject(BLACK_BRUSH));Ellipse(hdc,pt[0].x,pt[0].y,pt[1].x,pt[1].y);}}void DrawHands(HDC  hdc,SYSTEMTIME *pst,BOOL fChange){ static POINT pt[3][5] = { 0, -150, 100, 0, 0, 600, -100, 0, 0, -150,                               0, -200,  50, 0, 0, 800,  -50, 0, 0, -200,                               0,    0,   0, 0, 0,   0,    0, 0, 0,  800 } ;int i,iAngle[3];POINT ptTemp[3][5];iAngle[0]=(pst->wHour*30)%360+pst->wMinute/2;iAngle[1]=pst->wMinute*6;iAngle[2]=pst->wSecond*6;memcpy(ptTemp,pt,sizeof(pt));for(i=fChange?0:2;i<3;++i){RotatePoint(ptTemp[i],5,iAngle[i]);Polyline(hdc,ptTemp[i],5);}}LRESULT CALLBACK WindowProc(  HWND hwnd,      // handle to window  UINT uMsg,      // message identifier  WPARAM wParam,  // first message parameter  LPARAM lParam   // second message parameter){static int cxClient,cyClient;static SYSTEMTIME stPrevious;HDC hdc;bool fChange;PAINTSTRUCT ps;SYSTEMTIME st;switch(uMsg){case WM_CREATE:SetTimer(hwnd,ID_TIMER,1000,NULL);GetLocalTime(&st);stPrevious=st;return 0;case WM_SIZE:cxClient=GET_X_LPARAM(lParam);cyClient=GET_Y_LPARAM(lParam);return 0;case WM_TIMER:GetLocalTime(&st);fChange=st.wHour!=stPrevious.wHour||st.wMinute!=stPrevious.wMinute;hdc=GetDC(hwnd);SetIsotropic(hdc,cxClient,cyClient);SelectObject(hdc,GetStockObject(WHITE_PEN));DrawHands(hdc,&stPrevious,fChange);SelectObject(hdc,GetStockObject(BLACK_PEN));DrawHands(hdc,&st,TRUE);//InvalidateRect(hwnd,NULL,TRUE);ReleaseDC(hwnd,hdc);stPrevious=st;return 0;case WM_PAINT:hdc=BeginPaint(hwnd,&ps);SetIsotropic(hdc,cxClient,cyClient);DrawClock(hdc);DrawHands(hdc,&stPrevious,TRUE);EndPaint(hwnd,&ps);return 0;case WM_DESTROY:PostQuitMessage(0);return 0;}return DefWindowProc(hwnd,uMsg,wParam,lParam);}

 

怎么能没有效果图呢：

需要一点三角函数的知识，弄明白位置与角度的关系。