Gray Scale 2

using System.Drawing.Imaging;

public static Bitmap MakeGrayscale(Bitmap original)
{
    //create a blank bitmap the same size as original
    Bitmap newBitmap =
    new Bitmap(original.Width, original.Height);

    //get a graphics object from the new image
    Graphics g = Graphics.FromImage(newBitmap);

    //create the grayscale ColorMatrix
    ColorMatrix colorMatrix = new ColorMatrix(
    new float[][]{
        new float[] {.3f, .3f, .3f, 0, 0},
        new float[] {.59f, .59f, .59f, 0, 0},
        new float[] {.11f, .11f, .11f, 0, 0},
        new float[] {0, 0, 0, 1, 0},
        new float[] {0, 0, 0, 0, 1}});

    //create some image attributes
    ImageAttributes attributes = new ImageAttributes();

    //set the color matrix attribute
    attributes.SetColorMatrix(colorMatrix);

    //draw the original image on the new image
    //using the grayscale color matrix
    g.DrawImage(original,
    new Rectangle(0, 0, original.Width, original.Height),
    0, 0, original.Width, original.Height,
    GraphicsUnit.Pixel, attributes);

    //dispose the Graphics object
    g.Dispose();
    return newBitmap;
}

private void button1_Click(object sender, EventArgs e)
{
    Bitmap b = (Bitmap) pictureBox1.Image;
    pictureBox2.Image = MakeGrayscale(b);
}

Gray Scale

using System.Drawing.Imaging;

public Image GrayScaleImage(Graphics graph, Image img, int left, int top)
        {
                     
            ColorMatrix colorMix = new ColorMatrix();           
            colorMix.Matrix00 = 1 / 3f;
            colorMix.Matrix01 = 1 / 3f;
            colorMix.Matrix02 = 1 / 3f;
            colorMix.Matrix10 = 1 / 3f;
            colorMix.Matrix11 = 1 / 3f;
            colorMix.Matrix12 = 1 / 3f;
            colorMix.Matrix20 = 1 / 3f;
            colorMix.Matrix21 = 1 / 3f;
            colorMix.Matrix22 = 1 / 3f;

            ImageAttributes imgAttrib = new ImageAttributes();
            imgAttrib.SetColorMatrix(colorMix);

            graph.DrawImage(img, new Rectangle(left, top, img.Width,
                 img.Height), 0, 0, img.Width, img.Height,
                 GraphicsUnit.Pixel, imgAttrib);
            Bitmap bmp = new Bitmap(img);
            return bmp;

        }

Graphic Up

private void Form1_Paint(object sender, PaintEventArgs e)
{
    // حالت معمولی
    e.Graphics.DrawEllipse(new Pen(Color.Red, 10), 30, 30, 50, 50);

    //  SmoothingMode.AntiAlias  روانسازی به کمک
    e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
    e.Graphics.DrawEllipse(new Pen(Color.Blue, 10), 30, 100, 50, 50);
}

Follower

bool b = false;
        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            b = true;
            a.Clear();
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            b = false;

        }
        ArrayList a = new ArrayList();
        Point[] p = new Point[50];
        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (b == true)
            {
                a.Add(new Point(e.X, e.Y));
                if (a.Count >= 50)
                {
                    for (int i = 0; i < a.Count - 50; i++)
                    {
                        a.RemoveAt(i);
                    }

                    a.CopyTo(p);
                }
                else
                {
                    a.CopyTo(p);
                }
                Bitmap bp = new Bitmap(this.Width, this.Height);
                Graphics g = Graphics.FromImage(bp);
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
                Pen pn = new Pen(Brushes.Black);
                pn.Width = 2;
                pn.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;
                g.DrawLines(pn, p);
                this.BackgroundImage = bp;
            }

Filled Squere

private void Form1_Paint(object sender, PaintEventArgs e)
{
    Graphics g = e.Graphics;
    // Create pen.
    Pen blackPen = new Pen(Color.Black, 3);
    // Create points that define polygon.
    Point point1 = new Point(30, 50);
    Point point2 = new Point(100, 25);
    Point point3 = new Point(200, 5);
    Point point4 = new Point(250, 50);
    Point point5 = new Point(270, 100);
    Point point6 = new Point(250, 250);
    Point[] curvePoints = {point1, point2, point3, point4, point5, point6};
    // Draw polygon to screen.
    g.DrawPolygon(blackPen, curvePoints);
    // Fill polygon
    g.FillPolygon(Brushes.Red, curvePoints);
}