C# 实现Bresenham算法（vs2010）

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Drawing;

using System.Drawing.Drawing2D;

 

namespace Bresenham

{

    public partial class Form1 : Form

    {

        Graphics g;

        const int CellSize = 20;

        int iclick = 0;

        int Cols, Rows;

        Point A,B;

 

        public Form1()

        {

            InitializeComponent();

            g = CreateGraphics();

            Rows = this.Height / 20;

            Cols = this.Width / 20;

        }

 

        private void Form1_Load(object sender, EventArgs e)

        {

        }

 

        private void Form1_Paint(object sender, PaintEventArgs e)//程序启动时调用一次DrawSence()

        {

            DrawSence();

        }

 

        private void DrawSence()//绘制背景网格

        {

            int i, j;

            Point M, N;

            Pen p = new Pen(Brushes.Black, 1);

            g.Clear(Color.White);

            for (i = 0; i < Rows   1; i )

            {

                M = new Point(0, i * CellSize);

                N = new Point(Width, i * CellSize);

                g.DrawLine(p, M, N);

            }

            for (j = 0; j < Cols   1; j )

            {

                M = new Point(j * CellSize, 0);

                N = new Point(j * CellSize, Height);

                g.DrawLine(p, M, N);

            }                        

        }

 

        private void Form1_MouseClick(object sender, MouseEventArgs e)//记录鼠标坐标，并绘制位置

        {

            switch (iclick)

            {

                case 0:

                    {

                        A = new Point(e.X / CellSize, e.Y / CellSize);

                        DrawSence();

                        g.FillEllipse(Brushes.Red, A.X * CellSize, A.Y * CellSize, CellSize, CellSize);

                        iclick = 1;

                        break;

                    }

                case 1:

                    {

                        B = new Point(e.X / CellSize, e.Y / CellSize);

                        DoBresenham(A,B);

                        g.FillEllipse(Brushes.Red, B.X * CellSize, B.Y * CellSize, CellSize, CellSize);

                        g.FillEllipse(Brushes.Red, A.X * CellSize, A.Y * CellSize, CellSize, CellSize);

                        iclick = 0;

                        break;

                    }

            }

        }

        private void DoBresenham(Point p1,Point p2)//实现Bresenham算法，绘制离散像素点

        {

            int dx = p2.X - p1.X;

            int dy = p2.Y - p1.Y;

            int stepX = 0, stepY = 0;

            if (dx < 0)

            {

                dx = -dx;

                stepX = -1;

            }

            else

                stepX = 1;

            if (dy < 0)

            {

                dy = -dy;

                stepY = -1;

            }

            else

                stepY = 1;

 

            if (dx > dy)

            {

                int y = p1.Y;

                int d = 2 * dy - dx;

                for (int i = p1.X; i != p2.X; i  = stepX)

                {

                    g.FillEllipse(Brushes.Blue, i * CellSize, y * CellSize, 20, 20);

                    d = d   2 * dy;

                    if (d >= 0)

                    {

                        y  = stepY;

                        d = d - 2 * dx;

                    }

                }

            }

            else

            {

                int x = p1.X;

                int d = 2 * dx - dy;

                for (int i = p1.Y; i != p2.Y; i  = stepY)

                {

                    g.FillEllipse(Brushes.Blue, x * CellSize, i * CellSize, 20, 20);

                    d = d   2 * dx;

                    if (d >= 0)

                    {

                        x  = stepX;

                        d = d - 2 * dy;

                    }

                }

            }                                       

        }

    }

}