Use Color Matrix to gray the image : Color Matrix « 2D Graphics « C# / C Sharp

1. C# / C Sharp
2. 2D Graphics
3. Color Matrix

Use Color Matrix to gray the image

 

  using System;
  using System.Drawing;
  using System.Drawing.Drawing2D;
  using System.Collections;
  using System.ComponentModel;
  using System.Windows.Forms;
  using System.Data;
  using System.Drawing.Imaging;

  public class Form1 : System.Windows.Forms.Form
  {
    public Form1()
    {
      InitializeComponent();
    }
    private void InitializeComponent()
    {
      this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
      this.ClientSize = new System.Drawing.Size(292, 273);
      this.Text = "";
      this.Resize += new System.EventHandler(this.Form1_Resize);
      this.Paint += new System.Windows.Forms.PaintEventHandler(this.Form1_Paint);

    }
    static void Main() 
    {
      Application.Run(new Form1());
    }

    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {      
      Graphics g = e.Graphics;
      Bitmap bmp = new Bitmap("winter.jpg");
      g.FillRectangle(Brushes.White, this.ClientRectangle);

      // Create a color matrix
      // The value 0.6 in row 4, column 4 specifies the alpha value
      float[][] matrixItems = {
                                new float[] {1, 0, 0, 0, 0},
                                new float[] {0, 1, 0, 0, 0},
                                new float[] {0, 0, 1, 0, 0},
                                new float[] {0, 0, 0, 0.6f, 0}, 
                                new float[] {0, 0, 0, 0, 1}};
      ColorMatrix colorMatrix = new ColorMatrix(matrixItems);

      // Create an ImageAttributes object and set its color matrix
      ImageAttributes imageAtt = new ImageAttributes();
      imageAtt.SetColorMatrix(
        colorMatrix,
        ColorMatrixFlag.Default,
        ColorAdjustType.Bitmap);

      // Now draw the semitransparent bitmap image.
      g.DrawImage(bmp, this.ClientRectangle, 0.0f, 0.0f, bmp.Width, bmp.Height, 
                  GraphicsUnit.Pixel, imageAtt);

      imageAtt.Dispose();
    }

    private void Form1_Resize(object sender, System.EventArgs e)
    {
      Invalidate();
    }
  }


           
         
  

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