RGB, etc.

[samdv]

Now then, I know how to convert from RGB to long by using RGB(Red As Integer, Green As Integer, Blue As Integer), but how can I convert from a long value back to RGB?

It's puzzled me for a while and the only way I can think to do it is like this:

Dim redVal As Integer, greenVal As Integer, blueVal As Integer
Dim lngColour As Long
For redVal = 0 To 255
   For greenVal = 0 To 255
      For blueVal = 0 To 255
      If RGB(redVal, greenVal, blueVal) = lngColour Then
         'the RGB version of lngColour is redVal, greenVal, blueVal
         Exit Sub
      Else:
         'wrong colour, keep trying
      End If
      Next blueVal
   Next greenVal
Next redVal

This will work, but surely there's an easier way of doing it - this loops through 16 and a half million colours, and checks each one, and my computer crashes every time I try. I need to find it at the click of a mouse button, otherwise the purpose of the application is defied.

Anybody?

[parksie]

I answered this here:

http://forums.vb-world.net/showthrea...threadid=27064

although you may need to swap the blue and red around in the function, because it parses BGR values from the API.

[agent]

there are several ways of doing it. i can think of two, but this is my favorite:

Sub Value2RGB(color As Long, r As Long, g As Long, b As Long)
    Dim a As String
    
    a = Hex(color)
    a = String(6 - Len(a), "0") + a
    r = Val("&h" + Right(a, 2))
    g = Val("&h" + Mid(a, 3, 2))
    b = Val("&h" + Left(a, 2))
End Sub

you call it like this

Value2RGB color, r, g, b
'r, g, and b now contain the value of red, green, and blue (0 to 255)

[parksie]

agent - I don't like that method. Mine is safer, and considerably faster, because there is no need for string conversions - it's all done on the number, with integer arithmetic.

[DiGiTaIErRoR]

When I need RGB conversion I wrote my own code for it, pretty much the same as agent's and it worked perfectly.

[parksie]

Yes, but if you do it a lot, it really slows it down. Anyway, it's best to use the integer manipulations just from a tidiness point.