关于图像分割Snake算法（c#）的一些不解之惑，望大神指点

Question

我手头有一个别人的代码，是winform程序，其中包含了两个类，分别是FormSnake.cs和SnakeSharp.cs在FormSnake类中的鼠标事件里，用了一个动态数组presetContour来记录鼠标每次每次停留位置的坐标，在SnakeSarp中也定义一个数组snakePoints,我的问题是：presetContour里面是肯定有数据的，而snakePoints是怎么得到这些数据的。我把两个类的代码都放上来，请明白的前辈指点一下。

Answer 1

+++++++++++FrmSnake.cs++++++++++++++
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace SnakeSharp
{
public partial class FormSnake : Form
{
public FormSnake()
{
InitializeComponent();
}
Graphics graphics = null;
Image curImage = null;
Bitmap oriImage = null;
Point imageOrignal = new Point(0, 0);
List presetContour = null;
SnakeSharp snakeSharp = null;

    private void panelBMP_Paint(object sender, PaintEventArgs e)
    {
        try
        {
            SplitterPanel pnl = sender as SplitterPanel;
            if (pnl == null)
            {
                return;
            }
            if (curImage == null)
            {
                return;
            }
            e.Graphics.DrawImage(curImage, imageOrignal);
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    private void FormSnake_Load(object sender, EventArgs e)
    {
        buttonClear.Enabled = false;
        buttonSetContour.Enabled = false;
        buttonStart.Enabled = false;
        //buttonStop.Enabled = false;
        //buttonStep.Enabled = false;
    }

    private void buttonClear_Click(object sender, EventArgs e)
    {
        curImage = null;
        buttonClear.Enabled = true;
        buttonSetContour.Enabled = true;
        buttonStart.Enabled = true;
        //buttonStop.Enabled = false;
        //buttonStep.Enabled = false;
       // buttonLoadImage.Enabled = true;
        imageOrignal = new Point(0, 0);                                                                         
        presetContour = null;
        mainContainer.Panel1.Refresh();
    }
    bool isDrawingContour = false;
    bool isMouseDown = false;
    private void buttonSetContour_Click(object sender, EventArgs e)
    {
        isDrawingContour = true;
        buttonSetContour.Enabled = true;
        buttonStart.Enabled = true;
        presetContour = new List<Point>();
        snakeSharp = SnakeSharp.FromImage(oriImage);

        curImage = new Bitmap(snakeSharp.CachedImage);
        mainContainer.Panel1.Refresh();
    }
    private void splitContainer1_Panel1_MouseDown(object sender, MouseEventArgs e)
    {
        if (!isDrawingContour)
        {
            return;
        }
        else
        {
            isMouseDown = true;
        }
    }

    private void splitContainer1_Panel1_MouseUp(object sender, MouseEventArgs e)
    {

        if (isMouseDown)
        {

            isDrawingContour = false;
            isMouseDown = false;
            buttonSetContour.Enabled = true;
            buttonStart.Enabled = true;
            //buttonStep.Enabled = true; 
            graphics = Graphics.FromImage(curImage);
            Pen p = new Pen(Color.Green);
            if (presetContour.Count > 1)
            {
                graphics.DrawLine(p, presetContour[0], presetContour[presetContour.Count - 1]);
            }
            graphics.Save();
            mainContainer.Panel1.Refresh();
            textBoxInfo.AppendText("\r\n边界设定完毕，共设定" + presetContour.Count + "个点。");
            if (snakeSharp != null)
            {
                snakeSharp.SetCurcePoints(presetContour);
            }
        }
    }
    long mouseTick = 0;
    private void splitContainer1_Panel1_MouseMove(object sender, MouseEventArgs e)
    {

        if (isMouseDown && isDrawingContour)
        {
            long ticks = DateTime.Now.Ticks;

            if ((ticks - mouseTick) < 100 * 10000)
            {
                return;
            }

            mouseTick = ticks;
            Rectangle imageRec = new Rectangle(imageOrignal, curImage.Size);
            if (imageRec.Contains(e.Location))
            {
                Point pt = new Point(e.Location.X - imageOrignal.X, e.Location.Y - imageRec.Y);
                presetContour.Add(pt);

                graphics = Graphics.FromImage(curImage);
                Pen p = new Pen(Color.Green);
                graphics.DrawRectangle(p, pt.X-1, pt.Y-1, 3, 3);
                if (presetContour.Count > 1)
                {
                    graphics.DrawLine(p, presetContour[presetContour.Count - 2], presetContour[presetContour.Count - 1]);
                }
                graphics.Save();
                mainContainer.Panel1.Refresh();
            }
        }
    }

    private void buttonStart_Click(object sender, EventArgs e)
    {
        buttonStart.Enabled = false;
        buttonSetContour.Enabled = false;
        buttonClear.Enabled = false;
        //buttonStop.Enabled = true;
        //buttonStep.Enabled = false;
        isRunning = true;
        try
        {
           // snakeSharp.CurvatureThreshold = double.Parse(textBoxCurvatureThreshold.Text);
           // snakeSharp.GradientThreshold = byte.Parse(textBoxGradientThreshold.Text);
           // snakeSharp.PointsMovedThreshold = Int32.Parse(textBoxPtsmovedThreshold.Text);
           // snakeSharp.WillRemoveDead = checkBoxRemoveDeadpoint.Checked;
            backgroundWorker.RunWorkerAsync();//当执行BackgroundWorker.RunWorkerAsync方法时会触发DoWork该事件，并且传递DoWorkEventArgs参数
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    //private void buttonStop_Click(object sender, EventArgs e)
    //{

    //    backgroundWorker.CancelAsync();
  //  }

   // private void buttonStep_Click(object sender, EventArgs e)//单步运行
    //{
      //  try
        //{
          //  int steps = (int)numericSteps.Value;
            //snakeSharp.CurvatureThreshold = double.Parse(textBoxCurvatureThreshold.Text);
            //snakeSharp.GradientThreshold = byte.Parse(textBoxGradientThreshold.Text);
            //snakeSharp.PointsMovedThreshold = Int32.Parse(textBoxPtsmovedThreshold.Text);
            //snakeSharp.WillRemoveDead = checkBoxRemoveDeadpoint.Checked;
            //int ptsMoved = 0;
            //while (steps > 0)
            //{
              //  ptsMoved = snakeSharp.RunSnake();
                //textBoxInfo.AppendText("\r\n移动了" + ptsMoved + "个点。");
                //steps--;
            //}
            //curImage = new Bitmap(snakeSharp.CachedImage);
            //graphics = Graphics.FromImage(curImage);
            //Pen p = new Pen(Color.Green);


            //if (snakeSharp.SnakePoints.Length > 0)
            //{
              //  CurvePoint[] snakePoints = snakeSharp.SnakePoints;
               // foreach (CurvePoint pt in snakePoints)
                //{
                  //  graphics.DrawRectangle(p, pt.X-1, pt.Y-1, 3, 3);

                //}
               // for (int i = 0; i < snakePoints.Length; i++)
                //{
                  //  graphics.DrawLine(p, snakePoints[i].Pos, snakePoints[(i + 1)%snakePoints.Length].Pos);
                //}
            //}
            //graphics.Save();
            //mainContainer.Panel1.Refresh();
        //}
        //catch (Exception ex)
        //{
          //  MessageBox.Show(ex.Message);
        //}
    //}

    public bool isRunning { get; set; }

    private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
    {
        BackgroundWorker bgWorker = sender as BackgroundWorker;
        if (bgWorker == null)
        {
            return;
        }
        int ptsMoved = 0;
        while (!bgWorker.CancellationPending)
        {
            long ticks = DateTime.Now.Ticks;
            long currentTicks = DateTime.Now.Ticks;
            long interval = 500 * 10000;
            do
            {
                ptsMoved = snakeSharp.RunSnake();

                currentTicks = DateTime.Now.Ticks;
            } while (currentTicks - ticks < interval && ptsMoved > snakeSharp.PointsMovedThreshold);
            WorkState state = new WorkState();
            state.Points = new List<CurvePoint>();
            foreach (CurvePoint pt in snakeSharp.SnakePoints)
            {
                state.Points.Add(pt);
            }
            bgWorker.ReportProgress(10, state);//触发ProgressChanged事件

            if (ptsMoved <= snakeSharp.PointsMovedThreshold)
            {
                return;
            }
        }
    }

    private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        BackgroundWorker bgWorker = sender as BackgroundWorker;
        if (bgWorker == null)
        {
            return;
        }
        WorkState state = e.UserState as WorkState;
        if (state == null)
        {
            return;
        }
        curImage = new Bitmap(snakeSharp.CachedImage);
        graphics = Graphics.FromImage(curImage);
        Pen p = new Pen(Color.Green);
        if (state.Points.Count > 0)
        {

            foreach (CurvePoint pt in state.Points)
            {
                graphics.DrawRectangle(p, pt.X-1, pt.Y-1, 3, 3);
            }
            for (int i = 0; i < state.Points.Count ; i++)
            {
                graphics.DrawLine(p, state.Points[i].Pos, state.Points[(i + 1)%state.Points.Count].Pos);
            }
        }
        graphics.Save();
        mainContainer.Panel1.Refresh();
    }

    private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        //buttonStop.Enabled = false;
        buttonStart.Enabled = true;
        buttonSetContour.Enabled = true;
        buttonClear.Enabled = true;
        //buttonStep.Enabled = true;
        isRunning = false;
        textBoxInfo.AppendText("\r\n异步处理完毕");
    }

    private void textBoxPtsmovedThreshold_KeyPress(object sender, KeyPressEventArgs e)
    {
        int key = e.KeyChar;
        if ((key < 0x30 || key > 0x39) &&
            key != 0x08 /*&&  key != 46*/)
        {
            e.Handled = true;
        }
    }

    private void textBoxCurvatureThreshold_KeyPress(object sender, KeyPressEventArgs e)
    {
        int key = e.KeyChar;
        e.Handled = false;
        if ((key < 0x30 || key > 0x39) &&
            key != 0x08 && key != 46)
        {
            e.Handled = true;
            return;
        }
        if (key != 46)
        {
            return;
        }
     //   if (textBoxCurvatureThreshold.Text.Length <= 0)
      //  {
     //       e.Handled = true;
       //     return;
    //    }
      //  else
      //  {
          //  float f = 0.0f;
           // String newStr = textBoxCurvatureThreshold.Text + e.KeyChar;
           // bool b = float.TryParse(newStr, out f);
          //  e.Handled = !b;
      //  }
    }

    private void textBoxCurvatureThreshold_KeyUp(object sender, KeyEventArgs e)
    {

    }

    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)//复选框
    {
        //获取被选项目
        MyComboItem item = comboBox1.SelectedItem as MyComboItem;
        //执行操作

        if (comboBox1.SelectedItem.ToString() == "导入图片")
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.DefaultExt = ".bmp";
            ofd.Filter = "Image Files(*.bmp,*.jpg,*.png)|*.bmp;*.jpg;*.png||";
            if (DialogResult.OK != ofd.ShowDialog(this))
            {
                return;
            }
            Image tmpImage = Image.FromFile(ofd.FileName);
            textBoxInfo.AppendText("\r\n图片加载成功（" + ofd.FileName + "）");
            textBoxInfo.AppendText("\r\n图片大小：" + tmpImage.Width.ToString() + "X" + tmpImage.Height.ToString());
            Size clientSize = mainContainer.Panel1.ClientSize;
            Size newImageSize = new Size(tmpImage.Width, tmpImage.Height);
            if (tmpImage.Width > clientSize.Width || tmpImage.Height > clientSize.Height)
            {
                double rImage = tmpImage.Width * 1.0 / tmpImage.Height;
                double rWnd = clientSize.Width * 1.0 / clientSize.Height;
                if (rImage < rWnd) // image more high
                {
                    newImageSize.Height = clientSize.Height;
                    newImageSize.Width = (int)(newImageSize.Height * rImage);
                }
                else //image is more wide
                {

                    newImageSize.Width = clientSize.Width;
                    newImageSize.Height = (int)(newImageSize.Width / rImage);
                }
            }

            textBoxInfo.AppendText("\r\n调整图片大小为：" + newImageSize.Width + "X" + newImageSize.Height);
            oriImage = new Bitmap(tmpImage, newImageSize);
            snakeSharp = SnakeSharp.FromImage(oriImage);
            Bitmap bmpTmp = new Bitmap(newImageSize.Width, newImageSize.Height);
            for (int i = 0; i < newImageSize.Height; i++)
            {
                for (int j = 0; j < newImageSize.Width; j++)
                {
                    int val = (int)snakeSharp.ImageData[j, i];
                    if (val > 255) val = 255;
                    if (val < 0) val = 0;
                    bmpTmp.SetPixel(j, i, Color.FromArgb(val, val, val));
                }
            }
            curImage = new Bitmap(bmpTmp, newImageSize);
            imageOrignal = new Point((clientSize.Width - curImage.Width) / 2, (clientSize.Height - curImage.Height) / 2);

            mainContainer.Panel1.Refresh();
            buttonClear.Enabled = true;
            //buttonLoadImage.Enabled = true;
            buttonSetContour.Enabled = true;
        }
        else
        {
            ChildForm1 cf = new ChildForm1();
            cf.Show();
        }
    }
}
public class WorkState
{
    List<CurvePoint> points;
    public List<CurvePoint> Points
    {
        get { return points; }
        set { points = value; }
    }
}

}