main.cpp

一个动态画图程序

#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define Pi 3.1415926

long WINAPI WndProc(HWND hwnd,UINT iMessage,
					UINT wParam,LONG lParam);
double dfTheta=0,dfRange=100.0;		//正弦曲线的角度变量.
long i=0,j=0;
long lCentreX=0,lCentreY=0,lRadious=(long)(0.2*dfRange);
						//定义圆心坐标和圆半径.
POINT lpSin[100];	//定义正弦曲线的点坐标.

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInst,LPSTR lpszCmdLine,int nCmdShow)
{
	HWND hwnd;
	MSG Msg;
	WNDCLASS wndclass;
	char lpszClassName[]="SIN";
	char lpszTitle[]="test4_4";
	
	wndclass.style = 0;
	wndclass.lpfnWndProc = WndProc;
	wndclass.cbClsExtra = 0;
	wndclass.cbWndExtra = 0;
	wndclass.hInstance = hInstance;
	wndclass.hIcon = LoadIcon(NULL,IDI_APPLICATION);
	wndclass.hCursor = LoadCursor(NULL,IDC_ARROW);
	wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);

	wndclass.lpszMenuName = NULL;
	wndclass.lpszClassName = lpszClassName;
	
	if(!RegisterClass(&wndclass))
	{
		MessageBeep(0);
		return FALSE;
	}

	hwnd=CreateWindow
	(lpszClassName,			//窗口类名.
	lpszTitle,				//标题名.
	WS_OVERLAPPEDWINDOW,	//带标题栏,最大/小按钮的窗口
	CW_USEDEFAULT,	//窗口左上角坐标.
	0,						
	CW_USEDEFAULT,	//采用缺省的宽度和高度.
	0,
	NULL,			//无父窗口.
	NULL,			//无主菜单.
	hInstance,			//当前实例句柄.
	NULL);

	ShowWindow(hwnd,nCmdShow);	//显示窗口.
	UpdateWindow(hwnd);		//更新并绘制用户区.
	
	for(int j=0;j<100;j++)		//生成正弦曲线的点坐标.
	{
		lpSin[j].x=(long)(j*2*Pi/100*60);
		lpSin[j].y=(long)(dfRange*sin(j*2*Pi/100));
	}
	
	while(GetMessage(&Msg,0,0,0))
	{
		TranslateMessage(&Msg);	//消息循环.
		DispatchMessage(&Msg);
	}
	return Msg.wParam;
}

long WINAPI WndProc(HWND hwnd,UINT iMessage,
					UINT wParam,LONG lParam)
{
	HDC hDC;				//定义设备环境句柄.
	HBRUSH hBrush;			//定义画刷句柄
	HPEN hPen;				//定义画笔句柄
	PAINTSTRUCT PtStr;//定义包含绘图信息的结构体变量

	switch(iMessage)
{
  case WM_PAINT:				//处理绘图消息
	hDC=BeginPaint(hwnd,&PtStr);		//获得设备环境指针
	SetWindowOrgEx(hDC,-200,-200,NULL);//设置原点坐标
	hPen=CreatePen(PS_DASH,1,RGB(255,0,0));	//建新画笔
	SelectObject(hDC,hPen);				//选入画笔
	Polyline(hDC,lpSin,100);			//绘制正弦曲线

if(i<=25) //第一个1/4周期.
{	hPen=CreatePen(PS_DASH,1,RGB(255,0,0));	
	hBrush=CreateHatchBrush(HS_BDIAGONAL,RGB(255,0,0));
	lRadious=(long)(dfRange*0.2+i%25*dfRange*0.4/25);  //计算半径
}
else if(i<=50)//第二个1/4周期.
{	hPen=CreatePen(PS_DASH,1,RGB(0,255,0));
	hBrush=CreateHatchBrush(HS_DIAGCROSS,RGB(0,255,0));
	lRadious=(long)(dfRange*0.2+i%25*dfRange*0.4/25);
}
else if(i<=75)//第三个周期.
{	hPen=CreatePen(PS_DASH,1,RGB(0,0,255));
	hBrush=CreateHatchBrush(HS_CROSS,RGB(0,0,255));
	lRadious=(long)(dfRange*0.2+i%25*dfRange*0.4/25);
}
else//第四个周期.
{	hPen=CreatePen(PS_DASH,1,RGB(255,255,0));
	hBrush=CreateHatchBrush(HS_VERTICAL,RGB(255,255,0));
	lRadious=(long)(dfRange*0.2+i%25*dfRange*0.4/25);
}
		SelectObject(hDC,hBrush);	//选入画刷.
		SelectObject(hDC,hPen);	//选入画笔.
		lCentreX=lpSin[i].x;		//圆心x坐标.
		lCentreY=lpSin[i].y;		//圆心y坐标.
		Ellipse(hDC,lCentreX-lRadious,lCentreY-lRadious,
	  	           lCentreX+lRadious,lCentreY+lRadious);   //画圆

		i++;
		DeleteObject(hPen);		//删除画笔
		DeleteObject(hBrush);	//删除画刷
		EndPaint(hwnd,&PtStr);	//删除设备环境指针
		Sleep(100);			//停0.1秒
		if(i<100) InvalidateRect(hwnd,NULL,1);	//刷新用户区
		return 0;
	case WM_DESTROY:		//关闭窗口.
		PostQuitMessage(0);		return 0;
	default:
	         return(DefWindowProc(hwnd,iMessage,wParam,lParam));
	}
}