Windows编程 - Clock

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

LRESULT __stdcall WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI 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);
}