how can i get all pixels coordinate for shape boundary

Hi Frogleg, thanks for the code ;) you are really great, i learn a lot ;) thank you so much ;)

hi, i try to save the pixels coordinate from the listbox to txt file,

here is my code,

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;
using System.Collections;
using System.IO;
//c corner
namespace gettyPixel
{
    public partial class Form1 : Form
    {

        private Bitmap OriginalImage;
       // private Bitmap imgOut;
        private double BWThresh ;
        private Color cblack = System.Drawing.Color.FromArgb(255, 0, 0, 0);
        private Color cwhite = System.Drawing.Color.FromArgb(255, 255, 255, 255);
        //private ArrayList outList;



        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            BWThresh = 0.5;
        }

        private void bttnOpen_Click(object sender, EventArgs e)
        {

            openFileDialog1.Filter = "Image Files(*.PNG;*.JPG;*.GIF)|*.PNG;*.JPG;*.GIF";
            if (openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                pictureBox1.Image = null;
                Image img = Image.FromFile(openFileDialog1.FileName);// load image
                OriginalImage = new Bitmap(img.Width, img.Height);
                Graphics g = Graphics.FromImage(OriginalImage);// draw to bitmap
                g.DrawImage(img, 0, 0);
                pictureBox1.Image = Img2BW(OriginalImage, BWThresh);             
            }
        
        }
 

        private void bttnVertex_Click(object sender, EventArgs e)
        {
            /*
              display all pixels coordinate in listbox
             */          
                  
            ArrayList pxList = scan(OriginalImage);
            ShowVertexList(pxList);
           
            label1.Text = ("Listbox1 count = " + coordinate.Items.Count);
        }


        /* Convert the image into binary image*/
        // --> create a new B/W image from source image with brightness threshold = 0.5
        // --> this action is to make sure we only deal with black and white color
        private Bitmap Img2BW(Bitmap imgSrc, double threshold)
        {
            int width = imgSrc.Width;
            int height = imgSrc.Height;
            int px; double br;
            Color pixel;
            Bitmap imgOut = new Bitmap(imgSrc);
            for (int row = 0; row < height - 1; row++)
            {
                for (int col = 0; col < width - 1; col++)
                {
                    pixel = imgSrc.GetPixel(col, row);
                    px = pixel.ToArgb();
                    br = pixel.GetBrightness();
                    if (pixel.GetBrightness() < threshold)
                        imgOut.SetPixel(col, row, cblack);
                    else
                        imgOut.SetPixel(col, row, cwhite);
                }
            }
            return imgOut;
        }

        /* Show the pixels coordinate in listBox*/
        private void ShowVertexList(ArrayList al)
        {
            /*
             * Show the vertex in ListBox
             */
            coordinate.Items.Clear();
            Vertex prv;
            for (int k = 0; k < al.Count; k++)
            {
                prv = (Vertex)al[k];
                coordinate.Items.Add("{" + prv.X.ToString() + "," + prv.Y.ToString() + "}");
            }

                   }


        private ArrayList scan(Bitmap imgSrc)
        {
            pictureBox1.Refresh();
            Graphics g = pictureBox1.CreateGraphics();    
            ArrayList pixels = new ArrayList();

            for (int j = 0; j < imgSrc.Height; j++)
            {
                for (int i = 0; i < imgSrc.Width; i++)
                {
                    if (imgSrc.GetPixel(i, j) == cblack)
                    {
                        Vertex pix = new Vertex(i, j);
                        pixels.Add(pix);
                        if (checkBox1.Checked == false)
                        {
                            g.FillRectangle(Brushes.Red, i, j, 2, 2);
                        }
                       

                    }

                }
            }
          
            return pixels;
        }

        private void numericUpDown1_ValueChanged(object sender, EventArgs e)
        {
            BWThresh = Convert.ToDouble(numericUpDown1.Value);
        }

        private void button1_Click(object sender, EventArgs e)
        {
            saveFileDialog1.ShowDialog();           
           
        }

        private void saveFileDialog1_FileOk(object sender, CancelEventArgs e)
        {
            if (saveFileDialog1.FileName != "")
            {
                StreamWriter sw = new StreamWriter(saveFileDialog1.FileName);
                sw.WriteLine(coordinate.Items);
                sw.Close();
            }
        }

    }
}

but it does not return any file,

thanks

aznimah

Hi Frogleg,

i already try it ;) it return all the black pixels coordinate right. thanks for your help on my code. really thank you for your help, thank you so much ;)

hi Frogleg,

thanks for the reply,
what im trying to do is:

1) load an image

2) convert image to binary image so that the pixels color would be only black and white [0 or 1]

2) get display in listbox all the pixels coordinate which color black [1] only

i have try to code earlier but the code is not working, here is the code:



using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace PixelsCoordinate
{
    public partial class Form1 : Form
    {

        private Bitmap OriginalImage;
        private Bitmap imgOut;
        private double BWThresh = 0.5;
        private Color cblack = System.Drawing.Color.FromArgb(255, 0, 0, 0);
        private Color cwhite = System.Drawing.Color.FromArgb(255, 255, 255, 255);
        private ArrayList outList;

        public Form1()
        {
            InitializeComponent();
        }

        private void buttonOpen_Click(object sender, EventArgs e)
        {
            openFileDialog1.FileName = "";
            openFileDialog1.Title = "Images";
            openFileDialog1.Filter = "All Images|*.png; *.bmp; *.png";
            openFileDialog1.ShowDialog();
            if (openFileDialog1.FileName.ToString() != "")
            {
                pictureBox1.ImageLocation = openFileDialog1.FileName.ToString();
                OriginalImage = new Bitmap(openFileDialog1.FileName.ToString());
              
            }
        }


        private void buttonVertex_Click(object sender, EventArgs e)
        {
            /*
             * to convert image to binary image and display all pixels coordinate in listbox
             */
            Bitmap imgSrc = new Bitmap(OriginalImage);
            Bitmap imgOut = new Bitmap(imgSrc.Width, imgSrc.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);

            // --> create a new B/W image from source image with brightness threshold = 0.5
            // --> this action is to make sure we only deal with black and white color
            imgOut = Img2BW(imgSrc, BWThresh);
            ArrayList pxList = scan(imgOut);
            ShowVertexList(pxList);
        }

       

        /* Convert the image into binary image*/
        private Bitmap Img2BW(Bitmap imgSrc, double threshold)
        {
            int width = imgSrc.Width;
            int height = imgSrc.Height;
            int px; double br;
            Color pixel;
            Bitmap imgOut = new Bitmap(imgSrc);
            for (int row = 0; row < height - 1; row++)
            {
                for (int col = 0; col < width - 1; col++)
                {
                    pixel = imgSrc.GetPixel(col, row);
                    px = pixel.ToArgb();
                    br = pixel.GetBrightness();
                    if (pixel.GetBrightness() < threshold)
                        imgOut.SetPixel(col, row, cblack);
                    else
                        imgOut.SetPixel(col, row, cwhite);
                }
            }
            return imgOut;
        }

        /* Show the pixels coordinate in listBox*/
        private void ShowVertexList(ArrayList al)
        {
            /*
             * Show the vertex in ListBox
             */
            Vertex prv;
            for (int k = 0; k < al.Count; k++)
            {
                prv = (Vertex)al[k];
                coordinate.Items.Add("{" + prv.X.ToString() + "," + prv.Y.ToString() + "}");
            }
        }


        private ArrayList scan(Bitmap imgSrc)
        {
            coordinate.Items.Clear();
            Bitmap bp = new Bitmap(imgSrc);
            ArrayList pixels = new ArrayList();           
         
            for (int j = 0; j < bp.Height; j++)
            {
                for (int i = 0; i < bp.Width; i++)
                {
                    if (bp.GetPixel(i, j) == cblack)
                    {
                        Vertex pix = new Vertex(i, j);
                        pix.AddPixels(v);                            
                         
                    }
                                      
                }
            }
                      
            return pixels;
        }

       

        //private       

        class Vertex
        {
            ArrayList vertices = new ArrayList();
            private int x;
            private int y;
            public Vertex(int i, int j)
            {
                this.X = i;
                this.Y = j;
            }

            public void insert(Vertex v)
            {
                vertices.Add(v);
            }
            public ArrayList GetPixels()
            {
                return vertices;
            }
            public int GetCount()
            {
                return vertices.Count;
            }
            public void AddPixels(Vertex v)
            {
                vertices.Add(v);
            }
           
            public int X
            {
                get { return x; }
                set { x = value; }
            }

            public int Y
            {
                get { return y; }
                set { y = value; }
            }



        }

   
    }
}



really need help on this urgently, thank you so much

aznimah

you can use
Bitmap myBitmap = new Bitmap(yourWidth,yourHeight);
Color pixelColor = myBitmap.GetPixel(myX, myY);
int red = pixelColor.R;
int blue = pixelColor.B;
int green = pixelColor.G;
Then loop through myBitmap and check if red,blue and green = 0* and if so record myX and myY.
*You may need to check value between 0 & 10 to give yourself a bit of leeway