Duplicate
How do I adjust the brightness of a color?
How do I determine darker or lighter color variant of a given color?
Programmat
I changed Pavel Vladov function to modify even RGB component, to get shades on any combination of R/G/B directions:
Public Function ChangeColorShades(color As Color, correctionFactor As Single, bR As Boolean, bG As Boolean, bB As Boolean) As Color
Dim red As Single = CSng(color.R)
Dim green As Single = CSng(color.G)
Dim blue As Single = CSng(color.B)
If (correctionFactor < 0) Then
correctionFactor = 1 + correctionFactor
If bR Then
red *= correctionFactor
End If
If bG Then
green *= correctionFactor
End If
If bB Then
blue *= correctionFactor
End If
Else
If bR Then
red = (255 - red) * correctionFactor + red
End If
If bG Then
green = (255 - green) * correctionFactor + green
End If
If bB Then
blue = (255 - blue) * correctionFactor + blue
End If
End If
Return color.FromArgb(color.A, CInt(red), CInt(green), CInt(blue))
End Function