Windows程序设计之------简单时钟的实现

              Windows程序设计是利用API提供的接口进行的编写程序的过程，API（application programming interface）即应用程序编程接口。直接使用API编程是了解操作系统运行细节的最佳方式。

　　　　 由于课程实习要学这个，所以花了一个星期照着书，编译成功了第一个windows应用程序

　　　　这个程序是由几个部分组成的，分别是/try.cpp/try.h/stdafx.h......主要是try.cpp，话不多说，直接看代码吧！

// try.cpp : 定义应用程序的入口点。
//

#include "stdafx.h"
#include "try.h"
#include <windows.h>
#include <iostream>
#include <stdlib.h>

using namespace std;

#define MAX_LOADSTRING 100

// 全局变量:
HINSTANCE hInst;								// 当前实例
TCHAR szTitle[MAX_LOADSTRING];					// 标题栏文本
TCHAR szWindowClass[MAX_LOADSTRING];
// 主窗口类名
static int s_nPreHour;
static int s_nPreMinute;
static int s_nPreSecond;

static int s_cxClient;
static int s_cyClient;
static BOOL s_bTopMost;

// 此代码模块中包含的函数的前向声明:
ATOM				MyRegisterClass(HINSTANCE hInstance);
BOOL				InitInstance(HINSTANCE, int);
LRESULT CALLBACK	WndProc(HWND, UINT, WPARAM, LPARAM );
INT_PTR CALLBACK	About(HWND, UINT, WPARAM, LPARAM);

int APIENTRY _tWinMain(_In_ HINSTANCE hInstance,
                     _In_opt_ HINSTANCE hPrevInstance,
                     _In_ LPTSTR    lpCmdLine,
                     _In_ int       nCmdShow)
{
	UNREFERENCED_PARAMETER(hPrevInstance);
	UNREFERENCED_PARAMETER(lpCmdLine);

 	// TODO: 在此放置代码。
	MSG msg;
	HACCEL hAccelTable;

	// 初始化全局字符串
	LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
	LoadString(hInstance, IDC_TRY, szWindowClass, MAX_LOADSTRING);
	MyRegisterClass(hInstance);

	// 执行应用程序初始化:
	if (!InitInstance (hInstance, nCmdShow))
	{
		return FALSE;
	}

	hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_TRY));

	// 主消息循环:
	while (GetMessage(&msg, NULL, 0, 0))
	{
		if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
	}

	return (int) msg.wParam;
}



//
//  函数: MyRegisterClass()
//
//  目的: 注册窗口类。
//
inline ATOM MyRegisterClass(HINSTANCE hInstance)
{
	WNDCLASSEX wcex;

	char szClassName[]="MainWClsass";

	wcex.cbSize = sizeof(WNDCLASSEX);

	wcex.style			= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon			= LoadIcon(hInstance,(LPSTR)IDC_MYICON);//???
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(CreateSolidBrush(RGB(0xa6,0xca,0xf0)));//使窗口变成天蓝色
	wcex.lpszMenuName	= MAKEINTRESOURCE(IDC_TRY);
	wcex.lpszClassName	= szWindowClass;
	wcex.hIconSm		= LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

	return RegisterClassEx(&wcex);
}

//
//   函数: InitInstance(HINSTANCE, int)
//
//   目的: 保存实例句柄并创建主窗口
//
//   注释:
//
//        在此函数中，我们在全局变量中保存实例句柄并
//        创建和显示主程序窗口。
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd;

   hInst = hInstance; // 将实例句柄存储在全局变量中

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!hWnd)
   {
      return FALSE;
   }


   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

//
//  函数: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  目的: 处理主窗口的消息。
//
//  WM_COMMAND	- 处理应用程序菜单
//  WM_PAINT	- 绘制主窗口
//  WM_DESTROY	- 发送退出消息并返回
//
//


void DrawClockFace(HDC hdc)
{
	const int SQUARESIZE = 20;
	static POINT pt[]=
	{
		0,450,
		225,390,
		390,225,
		450,0,
		390,-225,
		225,-390,
		0,-450,
		-225,-390,
		-390,-225,
		-450,0,
		-390,225,
		-225,390
	};
	SelectObject(hdc,GetStockObject(BLACK_BRUSH));
	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);
	}
}

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);
}

void DrawHand(HDC hdc,int nLength,int nWidth,int nDegrees,COLORREF clrColor)
{
	double nRadians=(double)nDegrees*0.0174533;

	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 hOldPen=(HPEN)::SelectObject(hdc,hPen);

	MoveToEx(hdc,pt[0].x,pt[0].y,NULL);
	LineTo(hdc,pt[1].x,pt[1].y);

	SelectObject(hdc,hOldPen);
	DeleteObject(hPen);
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
						 LPARAM lParam)
{
	static int nNum;
	static int bSetTimer;
	char szText[56];
	PAINTSTRUCT ps;
	HDC hdc;

	SetTimer(hWnd,1,250,NULL);
	SetTimer(hWnd,2,10*1000,NULL);

	switch(message)
	{
	case WM_CREATE:
		SYSTEMTIME time;
		GetLocalTime(&time);
		s_nPreHour=time.wHour%12;
		s_nPreMinute=time.wMinute;
		s_nPreSecond=time.wSecond;
		SetTimer(hWnd,1,1000,NULL);
		break;
	case WM_PAINT:
		PAINTSTRUCT ps;
		hdc = BeginPaint(hWnd,&ps);
		SetIsotropic(hdc,s_cxClient,s_cyClient);
		DrawClockFace(hdc);
		//一小时时针走30度，一分钟时针0.5度
		DrawHand(hdc,200,8,s_nPreHour*30+s_nPreMinute/2,RGB(0,0,0));
		//一分钟分针走6度
		DrawHand(hdc,400,6,s_nPreMinute*6,RGB(0,0,0));
		//一秒钟秒针走6度
		DrawHand(hdc,400,1,s_nPreSecond*6,RGB(0,0,0));
		EndPaint(hWnd,&ps);
		break;
	case WM_TIMER:
		COLORREF crfColor;
		crfColor =RGB(0xa6,0xca,0xf0);
		if(IsIconic(hWnd))
			return 0;
		//SYSTEMTIME time;
		GetLocalTime(&time);
		//建标
		hdc = GetDC(hWnd);
		SetIsotropic(hdc,s_cxClient,s_cyClient);
		//擦除时针和分针
		if(time.wMinute != s_nPreMinute)
		{
			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;
		}
                //如果秒针改变就擦除秒针，并重画所有指针
		if(time.wSecond != s_nPreSecond)
		{
			DrawHand(hdc,400,1,s_nPreSecond*6,crfColor);//擦除秒针
                        //重画所有
			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;
		}
	
		break;
	case WM_CLOSE:
		
			KillTimer(hWnd,1);
			DestroyWindow(hWnd);
		break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	case WM_SIZE:
		s_cxClient = LOWORD(lParam);
		s_cyClient = HIWORD(lParam);
		break;
	}
	return DefWindowProc(hWnd,message,wParam,lParam);
}

// “关于”框的消息处理程序。
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
	UNREFERENCED_PARAMETER(lParam);
	switch (message)
	{
	case WM_INITDIALOG:
		return (INT_PTR)TRUE;

	case WM_COMMAND:
		if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
		{
			EndDialog(hDlg, LOWORD(wParam));
			return (INT_PTR)TRUE;
		}
		break;
	}
	return (INT_PTR)FALSE;
}