ATOM MyRegisterClass(HINSTANCE hInstance)
{WNDCLASSEXW wcex;  //窗口类结构wcex.cbSize = sizeof(WNDCLASSEX); //结构大小wcex.style          = CS_HREDRAW | CS_VREDRAW|CS_OWNDC;//CS:class style此窗口类派生的窗口具有的风格//CS_OWNDC使得windows将每次对DC的设置保存下来，CS_HREDRAW | CS_VREDRAW窗口大小变化就刷新wcex.lpfnWndProc    = WndProc;    //窗口函数指针                     wcex.cbClsExtra     = 0;  //紧跟在窗口类结构后的附加字节数wcex.cbWndExtra     = 0;  //紧跟在窗口事例后的附加字节数wcex.hInstance      = hInstance;//本模块的实例句柄wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_CLOCKWINDOW));//窗口左上角图标句柄wcex.hCursor        = LoadCursor(nullptr, IDC_ARROW);//光标句柄wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW); //背景画刷句柄wcex.lpszMenuName   = MAKEINTRESOURCEW(IDC_CLOCKWINDOW);//菜单名//wcex.lpszMenuName   =NULL;  //无菜单wcex.lpszClassName  = szWindowClass;  //此窗口类名wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));//小图标句柄return RegisterClassExW(&wcex);  //注册此窗口类
}

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{hInst = hInstance; // 将实例句柄存储在全局变量中HWND hWnd = CreateWindowW(szWindowClass,       //窗口类名szTitle,             //窗口标题WS_OVERLAPPEDWINDOW, //窗口风格 WS:window style                    CW_USEDEFAULT,       //初始位置X坐标CW_USEDEFAULT,       //初始位置Y坐标500,                 //宽度500,                 //高度nullptr,             //父窗口句柄nullptr,             //菜单句柄hInstance,           //程序实例句柄nullptr);            //用户数据if (!hWnd){return FALSE;}ShowWindow(hWnd, nCmdShow);  //显示窗口UpdateWindow(hWnd);          //刷新客户区return TRUE;
}

int APIENTRY wWinMain(_In_ HINSTANCE hInstance,_In_opt_ HINSTANCE hPrevInstance,_In_ LPWSTR    lpCmdLine,_In_ int       nCmdShow)
{UNREFERENCED_PARAMETER(hPrevInstance);UNREFERENCED_PARAMETER(lpCmdLine);// 初始化全局字符串
    LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);LoadStringW(hInstance, IDC_CLOCKWINDOW, szWindowClass, MAX_LOADSTRING);MyRegisterClass(hInstance);// 执行应用程序初始化: if (!InitInstance (hInstance, nCmdShow)){return FALSE;}HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_CLOCKWINDOW));MSG msg;// 主消息循环: while (GetMessage(&msg, nullptr, 0, 0))//GetMessage返回False程序结束
    {if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)){TranslateMessage(&msg);DispatchMessage(&msg);}}return (int) msg.wParam;  //程序结束时返回最后一个MSG的wParam。
}

    HWND hWnd;HDC hDC;hWnd = ::FindWindow(_TEXT("Notepad"), NULL);hDC = ::GetDC(hWnd);while (::IsWindow(hWnd)){    ::SetTextColor(hDC, RGB(255, 0, 0));::SetBkColor(hDC, RGB(0, 0, 0));::TextOut(hDC, 10, 10, _T("this is a test."), sizeof("this is a test.") - 2);HPEN hPen = CreatePen(NULL,4,RGB(255,255,255));::SelectObject(hDC, hPen);::SelectObject(hDC, ::GetStockObject(BLACK_BRUSH));Ellipse(hDC, 0, 0, 500, 500);Sleep(1000);::SelectObject(hDC, ::GetStockObject(WHITE_BRUSH));Ellipse(hDC, 0, 0, 500, 500);Sleep(1000);::SelectObject(hDC, ::GetStockObject(LTGRAY_BRUSH));Ellipse(hDC, 0, 0, 500, 500);Sleep(1000);::SelectObject(hDC, ::GetStockObject(GRAY_BRUSH));Ellipse(hDC, 0, 0, 500, 500);Sleep(1000);::SelectObject(hDC, ::GetStockObject(DKGRAY_BRUSH));Ellipse(hDC, 0, 0, 500, 500);Sleep(1000);::SelectObject(hDC, ::GetStockObject(DKGRAY_BRUSH));Ellipse(hDC, 0, 0, 500, 500);Sleep(1000);}ReleaseDC(hWnd, hDC);

            PAINTSTRUCT ps;HDC hdc = BeginPaint(hWnd, &ps);  //取得（窗口客户区无效区域）设备环境句柄//绘图代码//EndPaint(hWnd, &ps);HDC hdcW = ::GetWindowDC(hWnd);   //取得整个窗口设备环境句柄HDC hdcD = ::GetDC(hWnd);         //取得窗口客户区设备环境句柄(函数可用在任何地方)        

void SetIsotropic(HWND hWnd,HDC hdc)
{RECT rect;GetClientRect(hWnd, &rect);       //取得客户区大小::SetMapMode(hdc, MM_ANISOTROPIC);  //自定义坐标系MM_ANISOTROPIC：X!=Y,MM_ISOTROPIC:X=Y::SetWindowExtEx(hdc, 500, 500, NULL);   //逻辑刻度，第四个参数可用于返回原来的大小::SetViewportExtEx(hdc, rect.right, -rect.bottom, NULL); //像素刻度(坐标方向)，第四个参数可用于返回原来的大小::SetViewportOrgEx(hdc, rect.right / 2, rect.bottom / 2, NULL);  //修改坐标系(参照之前坐标系的位置坐标)，第四个参数可用于返回原来的原点
}

void paintClock(HWND hWnd,HDC hdc)
{HPEN hPenTri, hPenTime, hPenCent;HBRUSH hBrushTr, hBrushTime, hBrushCent;int colorUseR = (rand() % (255 - 0 + 1)) + 0;   //(rand() % (b-a+1))+ a; a~b随机数int colorUseG = (rand() % (255 - 0 + 1)) + 0;int colorUseB = (rand() % (255 - 0 + 1)) + 0;hPenTri = CreatePen(NULL, 4, RGB(255, colorUseG, 240));hBrushTr = ::CreateSolidBrush(RGB(255, colorUseG, 240));bankColor = RGB(255, colorUseG, 240);hPenTime = CreatePen(NULL, 4, RGB(colorUseR, 240, 240));hBrushTime = ::CreateSolidBrush(RGB(colorUseR, 240, 240));hPenCent = ::CreatePen(NULL, 4, RGB(240, 240, colorUseB));hBrushCent = ::CreateSolidBrush(RGB(240, 240, colorUseB));SetIsotropic(hWnd,hdc);
///三角形
    //SetDCBrushColor(hdc, RGB(255, 255, 255));//（无效）
    ::SelectObject(hdc, hPenTri);::SelectObject(hdc, hBrushTr);//POINT Mypoint[12] = { (250,10),(375,33.5),(466.5,125),(490,250),(466.5,375),(375,466.5),(250,490),(125,466.5),(33.5,375),(10,250),(33.5,125),(125,33.5) };//写法错误POINT Mypoint[12] = { 0,240,120,207.84,207.84,120,240,0,207.84,-120,120,-207.84,0,-240,-120,-207.84,-207.84,-120,-240,0,-207.84,120,-120,207.84 };//::ClientToScreen(hWnd, point);   //投射到屏幕坐标,返回至pointPOINT Mypoint1[3] = { Mypoint[0],Mypoint[4],Mypoint[8] };POINT Mypoint2[3] = { Mypoint[1],Mypoint[5],Mypoint[9] };POINT Mypoint3[3] = { Mypoint[2],Mypoint[6],Mypoint[10] };POINT Mypoint4[3] = { Mypoint[3],Mypoint[7],Mypoint[11] };//POINT Mypoint5[4]={ Mypoint1 ,Mypoint2,Mypoint3,Mypoint4}//不好用for循环简化操作，二维数组用不了？？Polygon(hdc, Mypoint1, 3);Polygon(hdc, Mypoint2, 3);Polygon(hdc, Mypoint3, 3);Polygon(hdc, Mypoint4, 3);
//圆形===============================================================
::SelectObject(hdc, hPenTime);::SelectObject(hdc, hBrushTime);//图形填充色for (int i = 0; i < 12; i++){Ellipse(hdc, Mypoint[i].x - 10, Mypoint[i].y - 10, Mypoint[i].x + 10, Mypoint[i].y + 10);}
//中心点加文本=======================================================
    ::SelectObject(hdc, hPenCent);::SelectObject(hdc, hBrushCent);::Ellipse(hdc, -5, 5, 5, -5);::SetTextColor(hdc, RGB(0, 0, 0));  //文字颜色//::SetBkColor(hdc, TRANSPARENT);  //文字背景色，设置为透明无效::SetBkMode(hdc, TRANSPARENT);  //文字背景透明
CString strText = _T("时钟");TextOut(hdc, -240, 240, (LPCWSTR)strText, sizeof(strText) - 2);
}

void DrawHand(HDC hdc, int nLength, int nWidth, int nDegrees, COLORREF clrColor)
{double nRadians = (double)nDegrees * 2 * 3.1415926 / 360;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;HPEN hPen = ::CreatePen(PS_SOLID, nWidth, clrColor);HPEN oldPen = (HPEN)::SelectObject(hdc, hPen);::MoveToEx(hdc, pt[0].x, pt[0].y, NULL);LineTo(hdc, pt[1].x, pt[1].y);::SelectObject(hdc, oldPen);::DeleteObject(hPen);
}

    case WM_CREATE:
//当一个应用程序通过CreateWindowEx函数或者CreateWindow函数请求创建窗口时发送此消息，(此消息在函数返回之前发送)。
        SYSTEMTIME time;::GetLocalTime(&time);s_PreHour = time.wHour%12;//取余s_PreMinute = time.wMinute;s_PreSecond = time.wSecond;SetTimer(hWnd,   //窗口句柄IDT_CLOCK,//TimerID1000,     //间隔NULL);     //计时器函数指针return 0;//它应当返回0以使得窗口的创建过程得以继续。如果对于这个消息程序返回-1，窗口将会被销毁。//并且CreateWindowEx或者CreateWindow函数将会返回一个值为NULL的句柄。

    case WM_TIMER:paintClock(hWnd, hDC);//paintClock(hWnd, hDC);重画了时钟面板，使得覆盖了旧的时钟指针if (::IsIconic(hWnd))   //如果窗口是最小化{return 0;}::GetLocalTime(&time);//HDC hDC = ::GetDC(hWnd);//(无法写在这里)SetIsotropic(hWnd, hDC);//建立坐标系if (time.wMinute != s_PreMinute){            //DrawHand(hDC, 140, 8, s_PreHour * 30 + s_PreMinute / 2, bankColor);//使用时钟面板颜色覆盖原指针//DrawHand(hDC, 170, 6, s_PreMinute * 6, bankColor);  //覆盖失败（不能使得指针颜色完全消失，如同在相同的两点好几条画好几条线，看起来线条变粗并不像一条直线）
            s_PreHour = time.wHour;s_PreMinute = time.wMinute;}if (time.wSecond != s_PreSecond){//DrawHand(hDC, 170, 1, s_PreSecond * 6, bankColor);//使用时钟面板颜色覆盖原指针DrawHand(hDC, 80, 6, s_PreHour * 30 + s_PreMinute / 2, RGB(0,0,0));DrawHand(hDC, 120, 4, s_PreMinute * 6, RGB(0, 0, 0));DrawHand(hDC, 170, 2, s_PreSecond * 6, RGB(0, 0, 0));s_PreSecond = time.wSecond;}//::MessageBeep(MB_ICONASTERISK);//发出“嘟嘟”声break;