Converting bitmap to grayscale

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• 

  Frogleg15y agoPosted Jan 17, 2011, 10:40 PM

  Accepted answer

  
  
  Bitmap bmp;
  public Form1()
  {
  InitializeComponent();
  }
  private void Form1_Load(object sender, EventArgs e)
  {
  // loadImage();//use this to autoload
  }
  public void loadImage()
  {
  Image img = Image.FromFile("po.bmp");
  bmp = new Bitmap(img.Width, img.Height);
  Graphics g = Graphics.FromImage(bmp);
  g.DrawImage(img, 0, 0);
  pictureBox1.Image = ConvertToGrayscale(bmp);
  }
  
  public Bitmap ConvertToGrayscale(Bitmap source)
  {
  Bitmap bm = new Bitmap(source.Width, source.Height);
  for (int y = 0; y < bm.Height; y++)
  {
  for (int x = 0; x < bm.Width; x++)
  {
  Color c = source.GetPixel(x, y);
  int luma = (int)(c.R * 0.3 + c.G * 0.59 + c.B * 0.11);
  bm.SetPixel(x, y, Color.FromArgb(luma, luma, luma));
  }
  }
  return bm;
  }
  private void button1_Click(object sender, EventArgs e)
  {
  loadImage();
  }
  Try this. To load automatically uncomment
  // loadImage();//use this to autoload
   or put loadImage(); in open file dialog
• KH

  Kip Hackman5y agoPosted Dec 23, 2020, 10:30 PM

  You can use LEADTOOLS Imaging Pro SDK technology in your application.

  https://www.leadtools.com/sdk/image-processing

  You can leverage the GrayscaleCommand class to convert an image to a grayscale image.

  Here is some sample code:

  1. using (RasterCodecs codecs = new RasterCodecs())  
  2. {  
  3.     string srcFileName = @"FILE PATH TO INPUT IMAGE";   
  4.     string destFileName = @"FILE PATH TO OUTPUT GRAYSCALE IMAGE";  
  5.     using (RasterImage image = codecs.Load(srcFileName, 24, CodecsLoadByteOrder.Bgr, 1, 1))  
  6.     {  
  7.         // Convert to 8-bit grayscale   
  8.         GrayscaleCommand command = new GrayscaleCommand();   
  9.         command.BitsPerPixel = 8;   
  10.         command.Run(image);   
  11.   
  12.         codecs.Options.Jpeg.Save.QualityFactor = 2;   
  13.         codecs.Save(image, destFileName, RasterImageFormat.Jpeg, 8);   
  14.     }  
  15. }   
• LM

  luci marginean15y agoPosted Jan 18, 2011, 7:10 AM

  Thank you verry much for you help...but I managed to make the program working last night...
         
  private void btnLoad_Click(object sender, EventArgs e)
          {
              OpenFileDialog fDialog = new OpenFileDialog();
  
              fDialog.Filter =
                  "Bitmaps |*.bmp| GIFs |*.gif| JPEGs |*.jpg;*.jpeg| TIFs |*.tif";
  
              fDialog.InitialDirectory = @"C:\Documents and Settings\Taticu\Desktop\Scoala\Poze proba";
             
              if (fDialog.ShowDialog() == DialogResult.OK)
              {
                  Image old = Image.FromFile(fDialog.FileName);
                  pcbImage.Image = (Image)Grayscale(new Bitmap(old));
                  pcbImage.SizeMode = PictureBoxSizeMode.AutoSize;
              }
  
          }
         
  public static Bitmap Grayscale(Bitmap original)
          {
             
              Bitmap newBitmap = new Bitmap(original.Width, original.Height);
              Graphics g = Graphics.FromImage(newBitmap);
              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}
                });
  
              ImageAttributes attributes = new ImageAttributes();
  
              attributes.SetColorMatrix(colorMatrix);
  
              g.DrawImage(original, new Rectangle(0, 0, original.Width, original.Height),
                 0, 0, original.Width, original.Height, GraphicsUnit.Pixel, attributes);
  
              g.Dispose();
              return newBitmap;
          }