Help with colors

General
1

Hello all,

I am reading the colors of an image that consists of grays, reds with black grid lines. I am using the grid as a “box” to size an object on a canvas.

My challenge comes in where not all blacks are equal. I was using this code, but it did not work universally:

If surf.Pixel( nx, ny) <> OrgColor Then
If surf.Pixel( nx, ny) = &c00000000 OR surf.Pixel(nx, ny) = &c03030300 Then

I think what I really need to do is something like this where a range of color values are acceptable:

if surf.Pixel( nx, ny) >= &c00000000 AND surf.Pixel( nx, ny) <= &c03030300 Then

However this fails in compile with the complaint" Undefined operator. Type color does not define “>=” with type color.

I also tried with this:
Dim col As Color = surf.Pixel( nx, ny)
if Col >= &c00000000 AND Col <= &c03030300 Then

but, it too fails with the same message.

Can anyone tell me how to do this?

Thank you!
Tim

2

I’m sure others will have better ideas than this, but you could use color.ToString.

3

try

dim tst as color = surf.Pixel( nx, ny) 
if   (tst.red + tst.green + tst.blue )  < 80  then   //arbitrary value.. experiment with the threshold?
//its dark
end if
4

You could do this with a method like this:

Function isBetween(compareColor as Color, firstColor as Color, secondColor as Color) as Boolean
    If compareColor.Red < min(firstColor.Red, secondColor.Red) or compareColor.Red > max(firstColor.Red, secondColor.Red) then
        Return False
    End If

     If compareColor.Green < min(firstColor.Green, secondColor.Green) or compareColor.Green > max(firstColor.Green, secondColor.Green) then
        Return False
    End If

    If compareColor.Blue < min(firstColor.Blue, secondColor.Blue) or compareColor.Blue > max(firstColor.Blue, secondColor.Blue) then
        Return False
    End If

    Return True
End Function
5

Thank you all!

Greg, your function works best. Norman had a suggestion too, and that helped, but yours really did a great job.

Also, I changed the location (nx, ny) where we inspect the color of the pixel. This helped cure the problem too.

Thanks again everyone!
Tim