Scanning and conversion of computer graphics circles (2)

Qing Dujun

Address: http://blog.csdn.net/qingdujun/article/details/40042591

This article uses a complete example to demonstrate the scanning and conversion of circles.

1) Create CP2 class

Header file: p2.h

// P2.h: interface for the CP2 class.////////////////////////////////////////////////////////////////////////#if !defined(AFX_P2_H__709052D1_45DA_4DF0_B5F2_15AC2B45687A__INCLUDED_)#define AFX_P2_H__709052D1_45DA_4DF0_B5F2_15AC2B45687A__INCLUDED_#if _MSC_VER > 1000#pragma once#endif // _MSC_VER > 1000//二维点类class CP2  {public:CP2();CP2(double x,double y);virtual ~CP2();public:         //方便访问，直接定义为共有double x;double y;};#endif // !defined(AFX_P2_H__709052D1_45DA_4DF0_B5F2_15AC2B45687A__INCLUDED_)

Implementation file: cp2.cpp

// P2.cpp: implementation of the CP2 class.////////////////////////////////////////////////////////////////////////#include "stdafx.h"#include "DrawCircle.h"#include "P2.h"#ifdef _DEBUG#undef THIS_FILEstatic char THIS_FILE[]=__FILE__;#define new DEBUG_NEW#endif//////////////////////////////////////////////////////////////////////// Construction/Destruction//////////////////////////////////////////////////////////////////////CP2::CP2(){}CP2::~CP2(){}

2) create a ccircle class

Header file circle. h

// Circle.h: interface for the CCircle class.////////////////////////////////////////////////////////////////////////#if !defined(AFX_CIRCLE_H__AFAF8AB9_D976_4D82_8750_DB3E7F64F45C__INCLUDED_)#define AFX_CIRCLE_H__AFAF8AB9_D976_4D82_8750_DB3E7F64F45C__INCLUDED_#if _MSC_VER > 1000#pragma once#endif // _MSC_VER > 1000#include "P2.h"class CCircle  {public:CCircle();virtual ~CCircle();void OneEight(double R,CDC *pDC);               //绘制1/8圆void SymmetryFill(double x, double y,CDC *pDC); //绘制，同时根据对称性填充其他的7/8private:CP2 Center;   //圆心};#endif // !defined(AFX_CIRCLE_H__AFAF8AB9_D976_4D82_8750_DB3E7F64F45C__INCLUDED_)

Implementation file: circle. cpp

// Circle.cpp: implementation of the CCircle class.////////////////////////////////////////////////////////////////////////#include "stdafx.h"#include "DrawCircle.h"#include "Circle.h"#include <math.h>#define Round(d) int(floor(d+0.5))//四舍五入宏定义#ifdef _DEBUG#undef THIS_FILEstatic char THIS_FILE[]=__FILE__;#define new DEBUG_NEW#endif//////////////////////////////////////////////////////////////////////// Construction/Destruction//////////////////////////////////////////////////////////////////////CCircle::CCircle(){//初始化圆心坐标Center.x = 200;Center.y = 200;}CCircle::~CCircle(){}void CCircle::OneEight(double R,CDC *pDC)     //绘制1/8圆{double x,y,d,xMax; d=1.25-R;       //第一个中点是(1,R-0.5)，代入隐函数得d（R为半径）x=0; y=R;       //从像素点(0,R)开始填充（圆最上方顶点处）xMax = R*cos(3.14/4); // x属于(0 ,R*(sqrt(2)/2) )范围，即cos(45°)for(x=0;x<=xMax;x++)  //（主方向为x）{SymmetryFill(x,y,pDC);//绘制，同时根据对称性填充其他的7/8if (d<0)d=d+2*x+3;    //当d(i)<0时，递推公式d(i+1)=d(i)+2x(i)+3else{d=d+2*(x-y)+5;//递推公式d(i+1)=d(i)+2[x(i)-y(i)]+5y--;} }}void CCircle::SymmetryFill(double x, double y,CDC *pDC) //绘制，同时根据对称性填充其他的7/8{       //定义圆的边界颜色 COLORREF  clr=RGB(255,0,0);//绘制，填充该点pDC->SetPixelV(Round(x+Center.x),Round(y+Center.y),clr);  //x,y//同时根据对称性填充其他的7/8像素点pDC->SetPixelV(Round(y+Center.x),Round(x+Center.y),clr);  //y,xpDC->SetPixelV(Round(y+Center.x),Round(-x+Center.y),clr); //y,-xpDC->SetPixelV(Round(x+Center.x),Round(-y+Center.y),clr); //x,-ypDC->SetPixelV(Round(-x+Center.x),Round(-y+Center.y),clr);//-x,-ypDC->SetPixelV(Round(-y+Center.x),Round(-x+Center.y),clr);//-y,-xpDC->SetPixelV(Round(-y+Center.x),Round(x+Center.y),clr); //-y,xpDC->SetPixelV(Round(-x+Center.x),Round(y+Center.y),clr); //-x,y}

3) ondraw Function

void CDrawCircleView::OnDraw(CDC* pDC){CDrawCircleDoc* pDoc = GetDocument();ASSERT_VALID(pDoc);// TODO: add draw code for native data hereCCircle *pCircle = new CCircle;pCircle->OneEight(100,pDC);}

4) Running Effect

Address: http://blog.csdn.net/qingdujun/article/details/40042591

References: tutorial on basic computer graphics (Visual C ++) (2nd) by Kong lingde

Scanning and conversion of computer graphics circles (2)