Draw a Clover

/*------------------------------------------------------------------------
   DEVCAPS1.C -- Device Capabilities Display Program No. 1
	         (c) Charles Petzold, 1998
 ----------------------------------------------------------------------*/
#include <windows.h>
#include<cmath>
#define NUM 1000
#define TWO_PI (2*3.14159)


LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
void DrawRectangle(HWND);

int cxClient, cyClient;
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
            PSTR szCmdLine, int iCmdShow)
{
	static TCHAR szAppName[] = TEXT ("Bezier") ;
	HWND 		hwnd ;
	MSG 		msg ;
	WNDCLASS 	wndclass ;

	wndclass.style 		= CS_HREDRAW | CS_VREDRAW ;
	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	= szAppName ;

	if (!RegisterClass (&wndclass))
	{
		MessageBox (	NULL, TEXT ("This program requires Windows NT!"),
             				szAppName, MB_ICONERROR) ;
		return 0 ;
     }

	hwnd = CreateWindow (	szAppName, TEXT ("Draw a Clover"),
                				WS_OVERLAPPEDWINDOW,
               				    CW_USEDEFAULT, CW_USEDEFAULT,
        				        CW_USEDEFAULT, CW_USEDEFAULT,
   				                NULL, NULL, hInstance, NULL) ;

	ShowWindow (hwnd, iCmdShow) ;
	UpdateWindow (hwnd) ;

	while (GetMessage (&msg, NULL, 0, 0))
     {
		TranslateMessage (&msg) ;
		DispatchMessage (&msg) ;
	}
	/*
	while(TRUE){
		if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
		{
			if(msg.message == WM_QUIT) break;
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}else
		{
			DrawRectangle(hwnd);//没有消息的时候
		}

	}*/
	return msg.wParam ;
}

void DrawBezier(HDC hdc, POINT apt[]){
	PolyBezier(hdc, apt, 4);
	MoveToEx(hdc, apt[0].x, apt[0].y,NULL);
	LineTo(hdc, apt[1].x ,apt[1].y);

	MoveToEx(hdc, apt[2].x, apt[2].y, NULL);
	LineTo(hdc, apt[3].x, apt[3].y);
}
void Draw(HWND hwnd, HDC hdc){
	 RECT rect;
     GetClientRect(hwnd, &rect);
	 for(int x = 0; x< rect.right;x+=10){
	     MoveToEx(hdc, x, 0, NULL);
		 LineTo(hdc, x, rect.bottom);
	 }
	 for(int y = 0; y< rect.bottom; y+=10){
	     MoveToEx(hdc, 0, y, NULL);
		 LineTo(hdc, rect.right, y);
	 }
}
LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	//static int	cxClient, cyClient;
	static HRGN hRgnClip;
	double fAngle, fRadius;
	HCURSOR  hCursor;
	HDC		hdc ;
	int		i ;
	HRGN    hRgnTemp[6];
	PAINTSTRUCT	ps ;
	TEXTMETRIC	tm ;

	switch (message)
     {
	case WM_SIZE:
		cxClient = LOWORD(lParam);
		cyClient = HIWORD(lParam);
		hCursor  = SetCursor(LoadCursor(NULL, IDC_WAIT));
		ShowCursor(TRUE);
		
		if(hRgnClip) DeleteObject(hRgnClip);
		hRgnTemp[0] = CreateEllipticRgn(0, cyClient/3,
			               cxClient/2, 2 * cyClient/3);
		hRgnTemp[1] = CreateEllipticRgn(cxClient/2,cyClient/3,
			               cxClient, 2 * cyClient/3);
		hRgnTemp[2]	= CreateEllipticRgn (cxClient / 3, 0,
						   2 * cxClient / 3, cyClient / 2) ;
		hRgnTemp[3]	= CreateEllipticRgn (cxClient / 3, cyClient / 2,
                            2 * cxClient / 3, cyClient) ;
		hRgnTemp[4]	= CreateRectRgn (0, 0, 1, 1) ;
		hRgnTemp[5]	= CreateRectRgn (0, 0, 1, 1) ;
		hRgnClip	= CreateRectRgn (0, 0, 1, 1) ;
		CombineRgn(hRgnTemp[4], hRgnTemp[0], hRgnTemp[1],RGN_OR);
		CombineRgn(hRgnTemp[5], hRgnTemp[2], hRgnTemp[3],RGN_OR);
		CombineRgn(hRgnClip, hRgnTemp[4], hRgnTemp[5],  RGN_XOR);

		for(i = 0; i< 6; i++) DeleteObject(hRgnTemp[i]);
		SetCursor(hCursor);
		ShowCursor(FALSE);

		return 0;

	case WM_PAINT:
		//InvalidateRect(hwnd, NULL, TRUE);
		hdc = BeginPaint(hwnd, &ps);
		SetViewportOrgEx(hdc, cxClient/2, cyClient/2, NULL);
		SelectClipRgn(hdc, hRgnClip);
		fRadius = _hypot(cxClient/2.0, cyClient / 2.0);
		for(fAngle = 0.0; fAngle < TWO_PI; fAngle += TWO_PI/360)
		{
			MoveToEx(hdc, 0, 0, NULL);
			LineTo(hdc, (int)(fRadius * cos(fAngle) + 0.5),
				        (int)(-fRadius* sin(fAngle) + 0.5));
		
		}
		/*矩形函数：
		  FillRect (hdc, &rect, hBrush) ;
		  FrameRect (hdc, &rect, hBrush) ;
		  InvertRect (hdc, &rect) ;
		  SetRect (&rect, xLeft, yTop, xRight, yBottom) ;
		  将矩形沿x轴和y轴移动几个单元：OffsetRect (&rect, x, y) ;
          增减矩形的尺寸：InflateRect (&rect, x, y) ;
          矩形各字段设定为0：SetRectEmpty (&rect) ;
          将矩形复制给另一个矩形：CopyRect (&DestRect, &SrcRect) ;
		  取得两个矩形的交集：IntersectRect (&DestRect, &SrcRect1, &SrcRect2) ;
		  取得两个矩形的联集：UnionRect (&DestRect, &SrcRect1, &SrcRect2) ;
		  确定矩形是否为空：bEmpty = IsRectEmpty (&rect) ;
		  确定点是否在矩形内：bInRect = PtInRect (&rect, point) ;
          您可以用下列叙述来替代CopyRect函数调用：DestRect = SrcRect ;		
		*/


		EndPaint(hwnd, &ps);
		
		
		
		
		return 0 ;

	case WM_DESTROY:
		DeleteObject(hRgnClip);
		PostQuitMessage (0) ;
		return 0 ;
	}
	return DefWindowProc (hwnd, message, wParam, lParam) ;
}

void DrawRectangle(HWND hwnd)
{
	HBRUSH hBrush;
	HDC    hdc;
	RECT   rect;
	if(cxClient==0 || cyClient == 0)return ;
	SetRect(&rect, rand()% cxClient, rand() % cyClient,
		           rand()% cxClient, rand() % cyClient);
	hBrush = CreateSolidBrush( RGB(rand() % 256, rand()%256, rand() % 256));
	hdc = GetDC(hwnd);
	FillRect(hdc, &rect, hBrush);
	//Sleep(10);
	ReleaseDC(hwnd, hdc);
	DeleteObject(hBrush);

}