多边形填充算法的实现 计算机图形学

多边形的填充算法有很多种，比如说边缘填充算法，栅栏填充算法，还有种子填充算法。种子填充算法和其他几种的算法采用的是完全不同的方法。

二、实验设备（环境）及要求

1、了解MATLAB软件基本操作，熟悉基本计算和绘图功能。

    2、环境要求：配有Windows XP及以上操作系统，安装MATLAB软件的完整版。

    3、实验过程中，务必仔细观察上机现象，记录必要信息，分析实验结果，按要求写出实验报告。

三、实验内容与步骤

题目：多边形填充算法的实现

四、实验结果与数据处理

    class CDrawView:public CView

    {

    protected://create from serialization only

        CDrawView();

        DECLARE_DYNCREATE(CDrawView)

    public:

        CDrawDoc*GetDocument();

    public:

        CPoint spt[7],s_point;

        ......

    }

    void CDrawView::OnDraw(CDC*pDC)

    {CDrawDoc*pDoc=GetDocument();

    ASSERT_VALID(pDoc);

    CPen newpen(PS_SOLID,1,RGB(0,0,255));

CPen*old=pDC->SelectObject(&newpen);

pDC->TextOut(20,20,"双击鼠标左键，生成多边形");

pDC->TextOut(20,50,"先在多边形内部单击鼠标右键，选择种子点，然后单击功能菜单实现填充");

pDC->SelectObject(old);

    }

    void CDrawView::OnSeedfill()

    {CclientDC dc(this);

    int fill=RGB(0,255,0);

    int boundary=RGB(0,0,255);

    int x,y,p0,pmin,pmax;

for(int m=1;m<7;m++)

    {

        for(int n=0;n<7-m;n++)

        {

            if(spt[n].y            {

                p0=spt[n].y；

                spt[n]=spt[n+1];

                spt[n+1]=p0;

            }

        }

    }

    pmax=spt[0].y;

    pmin=spt[6].y;

    x=s_point.x;y=s_point.y;

for(;y<=pmax;y++)

    {

        int current=dc.GetPixel(x,y);

        while((current!=boundary)&&(current!=fill))

        {

            dc.SetPixel(x,y,fill);

            x++;

            current=dc,GetPixel(x,y);

        }

        x=s-point.x;

        x--;

        current=dc.GetPixel(x,y);

        while((current!=boundary)&&(current!=fill))

        {

            dc.SetPixel(x,y,fill);

            x--;

            current=dc,GetPixel(x,y);

        }

        x=s-point.x;

    }

    x=s_point.x;y=s_point.y-1;

for(;y>=pmin;y--)

    {

        int current=dc.GetPixel(x,y);

        while((current!=boundary)&&(current!=fill))

        {

            dc.SetPixel(x,y,fill);

            x++;

            current=dc,GetPixel(x,y);

        }

        x=s-point.x;

        x--;

        current=dc.GetPixel(x,y);

        while((current!=boundary)&&(current!=fill))

        {

            dc.SetPixel(x,y,fill);

            x--;

            current=dc,GetPixel(x,y);

        }

        x=s-point.x;

    }

}

    void CDrawView::OnLButtonDblClk(UINT nFlags,CPoint point)

    {

        RedrawWindow();

        CDC*pDC=GetDC();

        CPen newpen(PS_SOLID,1,RGB(0,0,255));

CPen*old=pDC->SelectObject(&newpen);

        spt[0]=CPoint(100,100);

        spt[1]=CPoint(250,100);

        spt[2]=CPoint(250,250);

        spt[3]=CPoint(100,250);

        spt[4]=CPoint(150,200);

        spt[5]=CPoint(90,150);

        spt[6]=CPoint(160,150);

        spt[7]=CPoint(100,100);

pDC->SelectObject(old);

        CView::OnLButtonDblClk(nFlags,point);

    }

void CDrawView::OnLButtonDown(UINT nFlags,CPoint point)

{

s_point=pont;

CView::OnRButtonDown(nFlags,point);

}

    CView::OnLButtonDblClk(nFlags, point);

}

void CMy2dcadView::makeet()()

{    int p1=0,p2=1;

    int smally,bigy,smallx,bigx;

    Edge*ep1;

for(; p1        if(lhpoint[p1][1]==lhpoint[p2][1])

            continue;

        else if (lhpoint[p1][1]            smally=lhpoint[p1][1];

            bigy=lhpoint[p2][1];

            smallx=lhpoint[p1][0];

            bigx=lhpoint[p2][0];

        } else {

            smally=lhpoint[p2][1];

            bigy=lhpoint[p1][1];

            smallx=lhpoint[p2][0];

            bigx=lhpoint[p1][0];

    }

    ep1=new Edge;

ep1->ymax=bigy;

ep1->x=(float)smallx;

ep1->deltax=(float)(smallx-bigx)/(smally-bigy);

ep1->nextEdge=et[smally];

    et[smally]=ep1;

    }

}

void CMy2dcadView::OnRButtonDown(UINT nFlags,CPint point)

{

    //TODO:Add your message handler code here and/or call default

    CView::OnRButtonDown(nFlag,point);

    CClientDC dc(this);

    COLORREF Color;

    int scany=-1;

    int i=0,j=0;

    int k;

    int r,g,b;

    Edge*etp;

    makeet();

    while (et[++scany]==NULL);

While(scany<600){

        if(et[scany]!=NULL){

        etp=et[scany];

        while(etp){

            i=scany;

            while(iymax){

                j=(int)etp->x;

                j++;

                while(i<600){

                    Color=dc.GetPixel(j,i);

                    r=255--GetRValue(Color);

                    G=255--GetGValue(Color);

                    B=255--GetBValue(Color);

                    dc.GetPixel(j,i),RGB(r,g,b));

                    j++;}

                etp->x+=etp->deltax;

                i++;

            }

                etp->x+=etp->nextEdge;

        }

        et[scany]=NULL;

        }

        scany++;

    }

    npoint=20;

}

运行结果：

五、分析与讨论

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