[计算机图形学] 基于C#窗口的Bresenham直线扫描算法、种子填充法、扫描线填充法模拟软件设计（二）

             1
            //
            4-connected boundary-fill

             2
            //
            一种基于边界返回的四连通填充法，比如绘图颜料桶的作用
             3
            void BoundaryFill4(int x,int y,int fill,int boundary)
 4{
 5int current;
 6     current = getpixel(x, y);
 7if ((current != boundary) && (current != fill))
 8    {
 9        putpixel(x, y, fill);
10         BoundaryFill4(x+1, y, fill, boundary);
11         BoundaryFill4(x-1, y, fill, boundary);
12         BoundaryFill4(x, y+1, fill, boundary);
13         BoundaryFill4(x, y-1, fill, boundary);
14    }
15}
16//4-connected boundary-fill
17//一种基于新颜色返回的四连通填充法，最终多把内部和边界颜色涂成一样18void FloodFill4(int x,int y,int fillColor,int oldColor)
19{
20int current;
21     current = getpixel(x, y);
22if (current == oldColor)
23    {
24        putpixel(x, y, fillColor);
25         BoundaryFill4(x+1, y, fillColor, oldColor);
26         BoundaryFill4(x-1, y, fillColor, oldColor);
27         BoundaryFill4(x, y+1, fillColor, oldColor);
28         BoundaryFill4(x, y-1, fillColor, oldColor);
29    }
30 }

            1
            public Point[] pSearch_8 = 
2 { new Point(-1, 0), new Point(-1, 1), new Point(0, 1), new Point(1, 1),
3new Point(1, 0), new Point(1, -1), new Point(0, -1), new Point(-1, -1) 
4 };                                      //八联通填充八个方向偏移（原始偏移)5public Point[] pSearch_4 = 
6 { new Point(-1, 0), new Point(0, 1), new Point(1, 0), new Point(0, -1) 
7 };                                      //四联通填充四个方向偏移

             1
            void
             FloodSeedFill(Point a)

             2
            {

             3
            if (a.X < XiangSu / 2 || a.X > 508 || a.Y < XiangSu / 2 || a.Y > 440) return;//边界情况 4if(Vram[a.X + a.Y*600]==false)
 5    {
 6         Rectangle rect = new Rectangle(a.X - XiangSu / 2, a.Y - XiangSu / 2, XiangSu, XiangSu);
 7        g.FillEllipse(red, rect);
 8         Vram[a.X + a.Y * 600] = true;//标记已经走过 9if (checkBox.Checked == true)
10for (int i = 0; i < 4; i++)
11            {
12                 tempp.X = a.X + direction_4[i].X;
13                 tempp.Y = a.Y + direction_4[i].Y;
14                FloodSeedFill(tempp);
15            }
16else17for (int i = 0; i < 8; i++)
18            {
19                 tempp.X = a.X + direction_8[i].X;
20                 tempp.Y = a.Y + direction_8[i].Y;
21                FloodSeedFill(tempp);
22            } 
23    }
24 }

             1
            public
            class
             EDGE

             2
            {

             3
            public
            double xi;//边的下端点x坐标，在活化链表（AET）中，表示扫描线与边的交点x坐标 4publicdouble dx;//是个常量（直线斜率的倒数）（x + dx, y + 1） 5publicint ymax;//边的上顶点的y值 6publicstaticbooloperator <(EDGE a, EDGE b)//重载排列关系 7    {
 8return (Math.Abs(a.xi - b.xi)<1 ? a.dx < b.dx : a.xi < b.xi);
 9    }
10publicstaticbooloperator >(EDGE a, EDGE b)//重载排列关系11    {
12return (Math.Abs(a.xi - b.xi) < 1 ? a.dx > b.dx : a.xi > b.xi);
13    }
14publicstaticbooloperator ==(EDGE a, EDGE b)//重载等于号15    {
16return (Math.Abs(a.xi - b.xi)<1  && a.dx == b.dx && a.ymax == b.ymax);
17    }
18publicstaticbooloperator !=(EDGE a, EDGE b)//重载不等于号19    {
20return (Math.Abs(a.xi - b.xi)>1 || a.dx != b.dx || a.ymax != b.ymax);
21    }
22 }

             1
            public
            void ScanLinePolygonFill(List<Point> Q, Graphics g, int XiangSu)
 2{
 3this.XiangSu = XiangSu;
 4this.g = g;
 5 6     List<EDGE>[] NET = new List<EDGE>[500];//定义新边表 7for (int i = 0; i < 500; i++) NET[i] = new List<EDGE>();//实例化 8 9int ymax=0, ymin=0;//多边形y的最大值和最小值1011     GetPolygonMinMax(Q, out ymax, out ymin);//计算更新ymax和ymin(ok)12     InitScanLineNewEdgeTable(NET, Q, ymin, ymax);//初始化新边表13     HorizonEdgeFill(Q); //水平边直接画线填充14    ProcessScanLineFill(NET, ymin, ymax);
15 }

             1
            ///
            <summary>
             2
            ///
             初始化新边表

             3
            ///
             算法通过遍历所有的顶点获得边的信息，然后根据与此边有关的前后两个顶点的情况

             4
            ///
             确定此边的ymax是否需要-1修正。ps和pe分别是当前处理边的起点和终点，pss是起

             5
            ///
             点的前一个相邻点，pee是终点的后一个相邻点，pss和pee用于辅助判断ps和pe两个

             6
            ///
             点是否是左顶点或右顶点，然后根据判断结果对此边的ymax进行-1修正，算法实现非

             7
            ///
             常简单，注意与扫描线平行的边是不处理的，因为水平边直接在HorizonEdgeFill()

             8
            ///
             函数中填充了。

             9
            ///
            </summary>
            10
            private
            void InitScanLineNewEdgeTable(List<EDGE>[] NET, List<Point> Q, int ymin, int ymax)
11{
12     List<int> temp = new List<int>();
13    EDGE e;
14for (int i = 0; i < Q.Count; i++)
15    {
16         Point ps = Q[i];
17         Point pe = Q[(i + 1) % Q.Count];
18         Point pss = Q[(i - 1 + Q.Count) % Q.Count];
19         Point pee = Q[(i + 2) % Q.Count];
20if (pe.Y != ps.Y)//不处理平行线21        {
22             e = new EDGE();
23             e.dx = (double)(pe.X - ps.X) / (double)(pe.Y - ps.Y) * XiangSu;
24if (pe.Y > ps.Y)
25            {
26                 e.xi = ps.X;
27if (pee.Y >= pe.Y)
28                     e.ymax = pe.Y - XiangSu;
29else30                     e.ymax = pe.Y;
31                 NET[ps.Y - ymin].Add(e);//加入对应的NET里32                 temp.Add(ps.Y - ymin);
33            }
34else35            {
36                 e.xi = pe.X;
37if (pss.Y >= ps.Y)
38                     e.ymax = ps.Y - XiangSu;
39else40                     e.ymax = ps.Y;
41                 NET[pe.Y - ymin].Add(e);//加入对应的NET里42                 temp.Add(pe.Y - ymin);
43            }
44        }
45    }
46for (int i = 0; i < temp.Count; i++)
47    {
48         My_Sort(ref NET[temp[i]]);
49    }
50 }

             1
            private
            void ProcessScanLineFill(List<EDGE>[] NET, int ymin, int ymax)
 2{
 3     List<EDGE> AET=new List<EDGE>();//扫描线 4for (int y = ymin; y < ymax; y+=XiangSu)
 5    {
 6#region 显示运算信息
 7         g.DrawLine(new Pen(red),new Point(10,y),new Point(20,y));
 8         g.DrawString(AET.Count.ToString(), new Font("微软雅黑", 6), blue, new Point(2, y));
 9         InsertNetListToAet(NET[y-ymin], ref AET);
10         g.DrawString(y + " -> " + NET[y - ymin].Count + " -> " + AET.Count.ToString(), new Font("微软雅黑", 6), blue, new Point(25, y));
11for (int i = 0; i < AET.Count; i++)
12        {
13             g.DrawString((((int)AET[i].xi) / XiangSu * XiangSu).ToString() + "", new Font("微软雅黑", 6), blue, new Point(400 + i * 24, y));
14        }
15#endregion16         FillAetScanLine(ref AET, y);
17         RemoveNonActiveEdgeFromAet(ref AET, y);//删除非活动边18         UpdateAndResortAet(ref AET);//更新活动边表中每项的xi值，并根据xi重新排序19    }
20 }