1 泛洪填充算法(Flood Fill Algorithm)

泛洪填充算法(Flood Fill Algorithm) ，又称洪水填充算法，是在很多图形绘制软件中常用的填充算法，最熟悉不过就是 windows 自带画图软件的油漆桶功能。

2 源程序

using System;
using System.Collections;
using System.Collections.Generic;

namespace Legalsoft.Truffer.Algorithm
{
    /// <summary>
    /// 洪水填充算法
    /// </summary>
    public static partial class Algorithm_Gallery
    {
        private static void Fill_4Directions(int[,] screen, int x, int y, int prevC, int newC)
        {
            int M = screen.GetLength(0);
            int N = screen.GetLength(1);

            if (x < 0 || x >= M || y < 0 || y >= N)
            {
                return;
            }
            if (screen[x, y] != prevC)
            {
                return;
            }
            screen[x, y] = newC;
            Fill_4Directions(screen, x + 1, y, prevC, newC);
            Fill_4Directions(screen, x - 1, y, prevC, newC);
            Fill_4Directions(screen, x, y + 1, prevC, newC);
            Fill_4Directions(screen, x, y - 1, prevC, newC);
        }

        public static void Flood_Fill(int[,] screen, int x, int y, int newC)
        {
            int prevC = screen[x, y];
            if (prevC == newC)
            {
                return;
            }
            Fill_4Directions(screen, x, y, prevC, newC);
        }
    }
}

3 代码格式

using System;
using System.Collections;
using System.Collections.Generic;namespace Legalsoft.Truffer.Algorithm
{/// <summary>/// 洪水填充算法/// </summary>public static partial class Algorithm_Gallery{private static void Fill_4Directions(int[,] screen, int x, int y, int prevC, int newC){int M = screen.GetLength(0);int N = screen.GetLength(1);if (x < 0 || x >= M || y < 0 || y >= N){return;}if (screen[x, y] != prevC){return;}screen[x, y] = newC;Fill_4Directions(screen, x + 1, y, prevC, newC);Fill_4Directions(screen, x - 1, y, prevC, newC);Fill_4Directions(screen, x, y + 1, prevC, newC);Fill_4Directions(screen, x, y - 1, prevC, newC);}public static void Flood_Fill(int[,] screen, int x, int y, int newC){int prevC = screen[x, y];if (prevC == newC){return;}Fill_4Directions(screen, x, y, prevC, newC);}}
}