于八方向鏈碼的邊界跟蹤代碼，其中nVerct數(shù)組存儲的是邊界點的矢量方向，Coordinate存儲的是邊界點的坐標(biāo)。
//函數(shù) OnProcessTrace()
void CSkagonView::OnProcessTrace() 
{
    if(DibObject.pDib==NULL) 
    {
        MessageBox("請先載入一幅位圖","Error",MB_ICONERROR | MB_OK);
        return;
    }
    if(DibObject.GetNumberOfColors() != 256)
    {
        MessageBox("您處理的圖片不是256色圖","Error",MB_ICONERROR | MB_OK);
        return;
    }


    struct EdgePoint
    {
        BYTE nCurrenVerct;        //當(dāng)前矢量，即在輪廓跟蹤中的前一個搜索方向
        CPoint CurrenPoint;        //當(dāng)前點的坐標(biāo)
    };

    //CArray <EdgePoint,EdgePoint&> TraceArray;

    //獲取位圖的寬，高，以及每行字節(jié)數(shù)
    int nWidth=DibObject.GetWidth();
    int nByteWidth=DibObject.GetByteWidth();
    int nHeight=DibObject.GetHeight();

    //循環(huán)變量
    int i,j;

    //開辟一塊新的空間
    BYTE *pData=new BYTE[nByteWidth*nHeight];
    memset(pData,255,nByteWidth*nHeight);

    //像素值
    unsigned char pixel;

    //是否找到起始點及回到起始點
    bool bFindStartPoint;

    //是否掃描到一個邊界點
    bool bFindPoint;

    typedef struct 
    {
        int Width;
        int Height;
    }Position;

    //起始邊界點與當(dāng)前邊界點
    Position StartPoint,CurrentPoint;

    //八個方向和起始掃描方向，依次是左上方、上方、右上方、右方、右下方、下方、左下方和左方。
    int Direction[8][2]={ {-1,1},{0,1},{1,1},{1,0},{1,-1},{0,-1},{-1,-1},{-1,0} };
    int BeginDirect;


    //先找到最左下方的邊界點
    bFindStartPoint = false;
    for (j = 1;j < nHeight-1 && !bFindStartPoint;j++)
    {
        for(i = 1;i < nWidth-1 && !bFindStartPoint;i++)
        {
            //取得當(dāng)前指針處的像素值
            pixel = PointOld(i,j);
            
            if(pixel == 0)
            {
                bFindStartPoint = true;
                StartPoint.Height = j;
                StartPoint.Width = i;

                // 指向目標(biāo)圖像倒數(shù)第j行，第i個象素的指針            
                Point(i,j) = 0;
            }        
        }
    }

    //由于起始點是在左下方，故起始掃描沿左上方向
    BeginDirect = 0;
    //跟蹤邊界
    bFindStartPoint = false;
            
    CurrentPoint.Height = StartPoint.Height;
    CurrentPoint.Width = StartPoint.Width;

    int index=0;
    memset(nVerct,0,9999);

    
    while(!bFindStartPoint)
    {
        //從起始點一直找邊界，直到再次找到起始點為止
        bFindPoint = false;
        while(!bFindPoint)
        {
            //沿掃描方向，這里是左上方向獲取一個像素
            pixel = PointOld( CurrentPoint.Width + Direction[BeginDirect][0], 
                                CurrentPoint.Height + Direction[BeginDirect][1] );
            if(pixel == 0)
            {
                bFindPoint = true;

                //存儲邊界點的矢量方向
                nVerct[index] = (BYTE)BeginDirect;
                //存儲邊界點的坐標(biāo)
                Coordinate[index][0] = CurrentPoint.Width;
                Coordinate[index][1] = CurrentPoint.Height;
                index++;


                CurrentPoint.Width = CurrentPoint.Width + Direction[BeginDirect][0];
                CurrentPoint.Height = CurrentPoint.Height + Direction[BeginDirect][1];

                //如果一圈以后找到了起始點，那么邊界尋找完成
                if(CurrentPoint.Height == StartPoint.Height && 
CurrentPoint.Width == StartPoint.Width)
                {
                    bFindStartPoint = true;
                }
                //將輪廓在新的位圖中標(biāo)示出來
                Point(CurrentPoint.Width,CurrentPoint.Height) = 0;
                //掃描的方向逆時針旋轉(zhuǎn)兩格
                //為什么？因為逆時針旋轉(zhuǎn)三格的象素絕對不是邊界，不然當(dāng)前點就不會是邊界。
                BeginDirect--;
                if(BeginDirect == -1)
                    BeginDirect = 7;
                BeginDirect--;
                if(BeginDirect == -1)
                    BeginDirect = 7;
            }
            else
            {
                //掃描方向順時針旋轉(zhuǎn)一格
                BeginDirect++;
                if(BeginDirect == 8)
                    BeginDirect = 0;
            }

        }
    }    

    //邊界跟蹤時，邊界點數(shù)
    m_nNumNode =index;

    memcpy(DibObject.m_pData,pData,nByteWidth*nHeight);
    delete pData;
    FileIndex++;
    Invalidate();    //重繪
    
}