HSB and RGB Colours

[Trumpeter_Chris]

Does anyone know how to convert HSB colour values to RGB values, as I want to make some graphics that change through the spectrum with time.

Thanks

Chris

------------------
"Trust No One, Including Yourself"

[Paul282]

What's HSB? I have functions that convert a long to RGB componants or HEX to RGB... Am I playing the right sport?

[Trumpeter_Chris]

HSB stands for Hue (Pos. in Spectrum), Saturation (Intensity of Colour) and Brightness. It is useful for making rainbows or other nice effects.

------------------
"Trust No One, Including Yourself"

[G.Kumaraguru]

Hope this helps , with due credits to
Neil Pearson

'============================================

Function HSL(ByVal Hue As Integer, ByVal Sat As Integer, ByVal Lum As Integer)
Do While Hue > 359: Hue = Hue - 360: Loop
Do While Hue < 0: Hue = Hue + 360: Loop
If Sat > 100 Or Sat < 0 Then Exit Function
If Lum > 100 Or Lum < 0 Then Exit Function
Dim R As Integer, G As Integer, B As Integer
If Hue <= 60 Then
R = 255
G = CInt(Hue / 60 * 256)
B = 0
ElseIf Hue > 60 And Hue <= 120 Then
R = CInt((1 - (Hue - 60) / 60) * 256)
G = 255
B = 0
ElseIf Hue > 120 And Hue <= 180 Then
R = 0
G = 255
B = CInt((Hue - 120) / 60 * 256)
ElseIf Hue > 180 And Hue <= 240 Then
R = 0
G = CInt((1 - (Hue - 180) / 60) * 256)
B = 255
ElseIf Hue > 240 And Hue <= 300 Then
R = CInt((Hue - 240) / 60 * 256)
G = 0
B = 255
ElseIf Hue > 300 Then
R = 255
G = 0
B = CInt((1 - (Hue - 300) / 60) * 256)
End If
R = R + (50 - Sat) / 100 * (128 - R)
G = G + (50 - Sat) / 100 * (128 - G)
B = B + (50 - Sat) / 100 * (128 - B)
If Lum < 50 Then
R = (R / 50) * Lum
G = (G / 50) * Lum
B = (B / 50) * Lum
Else
R = Lum * ((255 - R) / 50) + 2 * R - 255
G = Lum * ((255 - G) / 50) + 2 * G - 255
B = Lum * ((255 - B) / 50) + 2 * B - 255
End If
If R > 255 Then R = 255
If G > 255 Then G = 255
If B > 255 Then B = 255
If R < 0 Then R = 0
If G < 0 Then G = 0
If B < 0 Then B = 0
HSL = RGB(R, G, B)
End Function

Sub RGB_To_HSL(R As Single, G As Single, B As Single)
'error checking:
If R < 0 Or R > 255 Or G < 0 Or G > 255 Or B < 0 Or B > 255 Then
'found an error, insert error handling code
H = 0: S = 0: L = 0
Exit Sub
End If
'syntax is valid, proceed
Dim Delta, CMin, CMax As Single 'declare floating-point variables
R = R / 255 'scale color channels
G = G / 255 'to values between
B = B / 255 'one and zero
CMax = R: CMin = R 'assume that read is highest and lowest
If CMax < G Then CMax = G: If CMin > G Then CMin = G 'if green is highest or lowest, replace with green value
If CMax < B Then CMax = B: If CMin > B Then CMin = B 'if blue is highest or lowest, replace with blue value
L = (CMax + CMin) / 2 'determine luminance (average of extremities)
If CMax = CMin Then 'color is greyscale, and has
S = 0 'no saturation and
H = 0 'unknown hue
Else
Delta = CMax - CMin 'range of colour values
If L < 0.5 Then 'determine saturation depending on luminance and
S = Delta / (CMax + CMin)
Else
S = Delta / (2 - CMax - CMin)
End If
Select Case CMax 'determine which color is most predominant
Case R: H = (G - B) / Delta 'hue is between 0 and 119
Case G: H = 2 + (B - R) / Delta 'hue is between 120 and 239
Case Else: H = 4 + (R - G) / Delta 'hue is between 240 and 359
End Select
H = H / 6 'scale hue back to decimal value
If H < 0 Then H = H + 1 'ensure that hue is positive
End If
H = CInt(H * 360) 'scale hue to degrees on color wheel
L = CInt(L * 100) 'scale luminance to percentage
S = CInt(S * 100) 'scale saturation to percentage
End Sub