Color shades rgb help

[tweaker99]

hello i recently got a response from you guys on how to, Search for a pixel and replace it well now im stuck on finding out how i could do shades, So im using this code

   Dim newImage As Bitmap = New Bitmap(PictureBox1.BackgroundImage)
        Dim bmp As Bitmap = DirectCast(PictureBox1.BackgroundImage, Bitmap)
        For x As Integer = 0 To bmp.Width - 1
            For y As Integer = 0 To bmp.Height - 1
                If bmp.GetPixel(x, y) = (Color.FromArgb(0, 0, 0)) Then
                    newImage.SetPixel(x, y, Color.White)
                    PictureBox2.BackgroundImage = newImage
                Else
                End If
            Next
        Next

now how could i have it. say if x,y= any shade of black Then.'Take Action'
im making my own paint type tool so im jw how i could paint all black even if it is just 1 digit off from 0,0,0'<- Black' or could someone give me some example code on how to loop threw some lines of r,g,b values so i could use that in my function

[boops boops]

Hi Tweaker, Here's a typical way to check if two colors match within a certain tolerance. I think that's what you are after.

You check if the Red, Green and Blue components are each within tolerance limits. For example:

Dim tolerance as Integer = 8
Dim testColor as Color = Color.Black

'then put this in the middle of the loop instead of just If bmp.GetPixel(x, y) = ...

Dim clr As Color = bmp.GetPixel(x, y)
If Math.Abs(clr.R - testColor.R) < tolerance AndAlso _
   Math.Abs(clr.G - testColor.G) < tolerance AndAlso _ 
   Math.Abs(clr.B - testColor.B) < tolerance Then _
   newImage.SetPixel(x, y, Color.White)
End If

You can obviously try this out with different colors and tolerances.

As minitech pointed out in the other thread, using GetPixel and SetPixel isn't the most efficient way to do pixel processing. But I think it's a good idea to get it working this way first, and leave speeding it up to later if it turns out to be necessary. (By the way, you should put PictureBox2.BackgroundImage = ... outside the loop, because otherwise you will be doing it thousands of times when you really only need to do it once.)

BB

[tweaker99]

Hi Tweaker, Here's a typical way to check if two colors match within a certain tolerance. I think that's what you are after.

You check if the Red, Green and Blue components are each within tolerance limits. For example:

Dim tolerance as Integer = 8
Dim testColor as Color = Color.Black

'then put this in the middle of the loop instead of just If bmp.GetPixel(x, y) = ...

Dim clr As Color = bmp.GetPixel(x, y)
If Math.Abs(clr.R - testColor.R) < tolerance AndAlso _
   Math.Abs(clr.G - testColor.G) < tolerance AndAlso _ 
   Math.Abs(clr.B - testColor.B) < tolerance Then _
   newImage.SetPixel(x, y, Color.White)
End If

You can obviously try this out with different colors and tolerances.

As minitech pointed out in the other thread, using GetPixel and SetPixel isn't the most efficient way to do pixel processing. But I think it's a good idea to get it working this way first, and leave speeding it up to later if it turns out to be necessary. (By the way, you should put PictureBox2.BackgroundImage = ... outside the loop, because otherwise you will be doing it thousands of times when you really only need to do it once.)

BB

wow man this was 100% exactly what i was looking for
Your amazing also pro Thanks So Much