C#，计算几何，计算机图形学（Computer Graphics）洪水填充算法（Flood Fill Algorithm）与源代码

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。

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);
		}
	}
}