一个API做的电子时钟

/////////////////////////////////////////////////////////////// // Clock.cpp文件 #include <windows.h> #include "resource.h" #include <math.h> LRESULT __stdcall WndProc(HWND, UINT, WPARAM, LPARAM); int __stdcall WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) { char szWindowClass[] = "Clock"; // 注册窗口类 WNDCLASSEX wcex; wcex.cbSize = sizeof(WNDCLASSEX); wcex.style = CS_HREDRAW | CS_VREDRAW; wcex.lpfnWndProc = (WNDPROC)WndProc; wcex.cbClsExtra = 0; wcex.cbWndExtra = 0; wcex.hInstance = hInstance; wcex.hIcon = ::LoadIcon(hInstance, (LPCTSTR)IDI_MAIN); wcex.hCursor = LoadCursor(NULL, IDC_ARROW); wcex.hbrBackground = (HBRUSH)(COLOR_3DFACE + 1); // 此域可以是一个系统定义的颜色值 wcex.lpszMenuName = NULL; wcex.lpszClassName = szWindowClass; wcex.hIconSm = NULL; ::RegisterClassEx(&wcex); // 创建并显示主窗口 HWND hWnd = ::CreateWindowEx(NULL, szWindowClass, "时钟", WS_POPUP|WS_SYSMENU|WS_SIZEBOX, 100, 100, 300, 300, NULL, NULL, hInstance, NULL); ::ShowWindow(hWnd, nShowCmd); ::UpdateWindow(hWnd); // 进入消息循环 MSG msg; while(::GetMessage(&msg, NULL, 0, 0)) { ::TranslateMessage(&msg); ::DispatchMessage(&msg); } return 1; } ////////////////////////////////////////////////////////////////////////////////////// // 消息处理代码 #define IDT_CLOCK 1 const int IDM_HELP = 100; const int IDM_TOPMOST = 101; // 实现函数 void SetIsotropic(HDC hdc, int cxClient, int cyClient); void DrawClockFace(HDC hdc); void DrawHand(HDC hdc, int nLength, int nWidth, int nDegrees, COLORREF clrColor); // 上一次Windows通知时的时间 static int s_nPreHour; // 小时 static int s_nPreMinute; // 分钟 static int s_nPreSecond; // 秒 // 窗口客户区的大小 static int s_cxClient; static int s_cyClient; // 是否位于最顶层 static BOOL s_bTopMost; LRESULT __stdcall WndProc(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam) { switch(nMsg) { case WM_CREATE: { // 向系统菜单中添加自定义的项 HMENU hSysMenu; hSysMenu = ::GetSystemMenu(hWnd, FALSE); ::AppendMenu(hSysMenu, MF_SEPARATOR, 0, NULL); ::AppendMenu(hSysMenu, MF_STRING, IDM_TOPMOST, "总在最前"); ::AppendMenu(hSysMenu, MF_STRING, IDM_HELP, "帮助"); // 设置时间 SYSTEMTIME time; ::GetLocalTime(&time); s_nPreHour = time.wHour%12; s_nPreMinute = time.wMinute; s_nPreSecond = time.wSecond; // 创建定时器 ::SetTimer(hWnd, IDT_CLOCK, 1000, NULL); return 0; } case WM_SIZE: { s_cxClient = LOWORD(lParam); s_cyClient = HIWORD(lParam); return 0; } case WM_PAINT: { PAINTSTRUCT ps; HDC hdc = ::BeginPaint(hWnd, &ps); // 设置坐标系 SetIsotropic(hdc, s_cxClient, s_cyClient); // 绘制时钟外观 DrawClockFace(hdc); // 绘制指针 // 经过1个小时时针走30度（360/12），经过1分钟时针走0.5度（30/60） DrawHand(hdc, 200, 8, s_nPreHour*30 + s_nPreMinute/2, RGB(0, 0, 0)); // 经过1分钟分针走6度（360/60） DrawHand(hdc, 400, 6, s_nPreMinute*6, RGB(0, 0, 0)); // 经过1秒钟秒针走6度（360/60） DrawHand(hdc, 400, 1, s_nPreSecond*6, RGB(0, 0, 0)); ::EndPaint(hWnd, &ps); return 0; } case WM_TIMER: { // 如果窗口处于最小化状态就什么也不做 if(::IsIconic(hWnd)) // IsIconic函数用来判断窗口是否处于最小化状态 return 0; // 取得系统时间 SYSTEMTIME time; ::GetLocalTime(&time); // 建立坐标系 HDC hdc = ::GetDC(hWnd); SetIsotropic(hdc, s_cxClient, s_cyClient); // 以COLOR_3DFACE为背景色就可以擦除指针了（因为窗口的背景色也是COLOR_3DFACE） COLORREF crfColor = ::GetSysColor(COLOR_3DFACE); // 如果分钟改变的话就擦除时针和分针 if(time.wMinute != s_nPreMinute) { // 擦除时针和分针 DrawHand(hdc, 200, 8, s_nPreHour*30 + s_nPreMinute/2, crfColor); DrawHand(hdc, 400, 6, s_nPreMinute*6, crfColor); s_nPreHour = time.wHour; s_nPreMinute = time.wMinute; } // 如果秒改变的话就擦除秒针，然后重画所有指针 if(time.wSecond != s_nPreSecond) { // 擦除秒针 DrawHand(hdc, 400, 1, s_nPreSecond*6, crfColor); // 重画所有指针 DrawHand(hdc, 400, 1, time.wSecond*6, RGB(0, 0, 0)); DrawHand(hdc, 200, 8, time.wHour*30 + time.wMinute/2, RGB(0, 0, 0)); DrawHand(hdc, 400, 6, time.wMinute*6, RGB(0, 0, 0)); s_nPreSecond = time.wSecond; } return 0; } case WM_CONTEXTMENU: POINT pt; pt.x = LOWORD(lParam); pt.y = HIWORD(lParam); { // 取得系统菜单的句柄 HMENU hSysMenu = ::GetSystemMenu(hWnd, FALSE); // 弹出系统菜单 int nID = ::TrackPopupMenu(hSysMenu,TPM_LEFTALIGN|TPM_RETURNCMD, pt.x, pt.y, 0, hWnd, NULL); if(nID > 0) ::SendMessage(hWnd, WM_SYSCOMMAND, nID, 0); return 0; } case WM_CLOSE: { ::KillTimer(hWnd, IDT_CLOCK); ::DestroyWindow(hWnd); return 0; } case WM_DESTROY: { ::PostQuitMessage(0); return 0; } case WM_NCHITTEST: { UINT nHitTest; nHitTest = ::DefWindowProc(hWnd, WM_NCHITTEST, wParam, lParam); if (nHitTest == HTCLIENT && ::GetAsyncKeyState(MK_LBUTTON) < 0) // 如果鼠标左键按下，GetAsyncKeyState函数的返回值小于0 nHitTest = HTCAPTION; return nHitTest; } case WM_SYSCOMMAND: int nID = wParam; { if(nID == IDM_HELP) { ::MessageBox(hWnd, "一个时钟的例子", "时钟", 0); } else if(nID == IDM_TOPMOST) { HMENU hSysMenu = ::GetSystemMenu(hWnd, FALSE); if(s_bTopMost) { ::CheckMenuItem(hSysMenu, IDM_TOPMOST, MF_UNCHECKED); ::SetWindowPos(hWnd, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOREDRAW | SWP_NOSIZE); s_bTopMost = FALSE; } else { ::CheckMenuItem(hSysMenu, IDM_TOPMOST, MF_CHECKED); ::SetWindowPos(hWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOREDRAW | SWP_NOSIZE); s_bTopMost = TRUE; } } return ::DefWindowProc(hWnd, WM_SYSCOMMAND, nID, 0); } } return ::DefWindowProc(hWnd, nMsg, wParam, lParam); } void SetIsotropic(HDC hdc, int cx, int cy) { ::SetMapMode(hdc, MM_ISOTROPIC); ::SetWindowExtEx(hdc, 1000, 1000, NULL); ::SetViewportExtEx(hdc, cx, -cy, NULL); ::SetViewportOrgEx(hdc, cx/2, cy/2, NULL); } // 绘制时钟的外观 void DrawClockFace(HDC hdc) { const int SQUARESIZE = 20; static POINT pt[] = { 0, 450, // 12点 225, 390, // 1点 390, 225, // 2点 450, 0, // 3点 390, -225, //... 下面的坐标是上面的点的对称点（以X轴、Y轴或原点对称） 225, -390, 0, -450, -225, -390, -390, -225, -450, 0, -390, 225, -225, 390 }; // 选择一个黑色的画刷 ::SelectObject(hdc, ::GetStockObject(BLACK_BRUSH)); // 画12个圆 for(int i=0; i<12; i++) { ::Ellipse(hdc, pt[i].x - SQUARESIZE, pt[i].y + SQUARESIZE, pt[i].x + SQUARESIZE, pt[i].y - SQUARESIZE); } } // 指针的长度、宽度、相对于0点偏移的角度、颜色分别由参数nLength、nWidth、nDegrees、clrColor指定 void DrawHand(HDC hdc, int nLength, int nWidth, int nDegrees, COLORREF clrColor) { // 将角度nDegrees转化成弧度 . 2*3.1415926/360 == 0.0174533 double nRadians = (double)nDegrees*0.0174533; // 计算坐标 POINT pt[2]; pt[0].x = (int)(nLength*sin(nRadians)); pt[0].y = (int)(nLength*cos(nRadians)); pt[1].x = -pt[0].x/5; pt[1].y = -pt[0].y/5; // 创建画笔，并选如DC结构中 HPEN hPen = ::CreatePen(PS_SOLID, nWidth, clrColor); HPEN hOldPen = (HPEN)::SelectObject(hdc, hPen); // 画线 ::MoveToEx(hdc, pt[0].x, pt[0].y, NULL); ::LineTo(hdc, pt[1].x, pt[1].y); ::SelectObject(hdc, hOldPen); ::DeleteObject(hPen); }