Question

This is my bitmap object

Bitmap b = new Bitmap(columns, rows, PixelFormat.Format8bppIndexed);
BitmapData bmd = b.LockBits(new Rectangle(0, 0, columns, rows), ImageLockMode.ReadWrite, b.PixelFormat);

How do i convert this into a 8 bit grayscale bitmap ?

Answer 1

hi you could change the color palette to a grayscale one

although the following code is in Vb.net. You could easily convert it to C#

Private Function GetGrayScalePalette() As ColorPalette  
    Dim bmp As Bitmap = New Bitmap(1, 1, Imaging.PixelFormat.Format8bppIndexed)  

    Dim monoPalette As ColorPalette = bmp.Palette  

    Dim entries() As Color = monoPalette.Entries  

    Dim i As Integer 
    For i = 0 To 256 - 1 Step i + 1  
        entries(i) = Color.FromArgb(i, i, i)  
    Next 

    Return monoPalette  
End Function 

Original Source -> http://social.msdn.microsoft.com/Forums/en-us/vblanguage/thread/500f7827-06cf-4646-a4a1-e075c16bbb38