# Splitting a colour into R G B values

A

#### Andrew Black (delete obvious bit)

Hi
Are there functions that can split a colour value into its component rgb
If I give
colour = RGB ( 255,0,0)
I would like
red (colour) returns 255
green (colour) ..... 0

Cheers

The colour value is actually RGB, but in the reverse order. If you convert
any value back to Hex, you'll see that the first 2 digits are the Blue
value, the middle 2 digits are the Green value and the last 2 digits are the
Red value.

Therefore, the following will work:

Function Red(ColourValue As Long) As Long
Dim strHexColour As String

strHexColour = Right\$("000000" & Hex(ColourValue), 6)
Red = CLng("&H" & Right\$(strHexColour, 2))

End Function

Function Green(ColourValue As Long) As Long
Dim strHexColour As String

strHexColour = Right\$("000000" & Hex(ColourValue), 6)
Green = CLng("&H" & Mid\$(strHexColour, 3, 2))

End Function

Function Blue(ColourValue As Long) As Long
Dim strHexColour As String

strHexColour = Right\$("000000" & Hex(ColourValue), 6)
Blue = CLng("&H" & Left\$(strHexColour, 2))

End Function

A couple of more methods.

1) If the color value could be a System Color Constant or an OLE color
then you really should use this method:
http://www.vbaccelerator.com/tips/vba0018.htm

2) The standard method is here:
http://support.microsoft.com/default.aspx?scid=http://support.microsoft.
com:80/support/kb/articles/Q112/0/61.asp&NoWebContent=1

3) If performance is a concern then:

Private Declare Sub apiCopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
(Destination As Any, Source As Any, ByVal Length As Long)

' Break apart the passed RGB values
Dim aRGBStart(0 To 3) As Byte

' Individual RGB bytes
Dim Bstart As Byte
Dim Gstart As Byte
Dim Rstart As Byte

' Break out into RGB bytes
apiCopyMemory aRGBStart(0), RGBStart, 4

Bstart = aRGBStart(2)
Gstart = aRGBStart(1)
Rstart = aRGBStart(0)

If you really want to understand more read on:

For information on Window's System Color Indexes see:
http://support.microsoft.com/support/kb/articles/Q186/0/62.ASP?

To understand how to seperate a long RGB Color value back to its RGB
components see:
http://support.microsoft.com/support/kb/articles/Q112/0/61.asp

For a detailed online Color FAQ see:
http://www.inforamp.net/~poynton/Poynton-color.html
Specifically:
http://www.inforamp.net/~poynton/ColorFAQ.html

For information on how windows represents colors see:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/col
ors_87zn.asp

Working with Color

Visual Basic uses a consistent system for all color properties and
graphics methods. A color is represented by a Long integer, and this
value has the same meaning in all contexts that specify a color.

Specifying Colors at Run Time
There are four ways to specify a color value at run time:

Use the RGB function.

Use the QBColor function to choose one of 16 Microsoft QuickBasic®
colors.

Use one of the intrinsic constants listed in the Object Browser.

Enter a color value directly.
This section discusses how to use the RGB and QBColor functions as
simple ways to specify color. See "Using Color Properties" later in this
chapter for information on using constants to define color or directly
entering color values.

Using the RGB Function
You can use the RGB function to specify any color.

To use the RGB function to specify a color

Assign each of the three primary colors (red, green, and blue) a number
from 0 to 255, with 0 denoting the least intensity and 255 the greatest.

Give these three numbers as input to the RGB function, using the order
red-green-blue.

Assign the result to the color property or color argument.
Every visible color can be produced by combining one or more of the
three primary colors. For example:

' Set background to green.
Form1.BackColor = RGB(0, 128, 0)
' Set background to yellow.
Form2.BackColor = RGB(255, 255, 0)
' Set point to dark blue.
PSet (100, 100), RGB(0, 0, 64)

Function" in the Language Reference.

Using Color Properties

Many of the controls in Visual Basic have properties that determine the
colors used to display the control. Keep in mind that some of these
properties also apply to controls that aren't graphical. The following
table describes the color properties.

Property Description
BackColor Sets the background color of the form or control used for
drawing. If you change the BackColor property after using graphics
methods to draw, the graphics are erased by the new background color.
ForeColor Sets the color used by graphics methods to create text or
graphics in a form or control. Changing ForeColor does not affect text
BorderColor Sets the color of the border of a shape control.
FillColor Sets the color that fills circles created with the Circle
method and boxes created with the Line method.

properties, see "BackColor Property," "ForeColor Property," "BorderColor
Property," and "FillColor Property" in the Language Reference.

Defining Colors
The color properties can use any of several methods to define the color
value. The RGB function described in "Working with Color" is one way to
define colors. This section discusses two more ways to define colors:

Using defined constants

Using direct color settings
Using Defined Constants
You don't need to understand how color values are generated if you use
the intrinsic constants listed in the Object Browser. In addition,
intrinsic constants do not need to be declared. For example, you can use
the constant vbRed whenever you want to specify red as a color argument
or color property setting:

BackColor = vbRed

Using Direct Color Settings
Using the RGB function or the intrinsic constants to define color are in
direct methods. They are indirect because Visual Basic interprets them
into the single approach it uses to represent color. If you understand
how colors are represented in Visual Basic, you can assign numbers to
color properties and arguments that specify color directly. In most
cases, it's much easier to enter these numbers in hexadecimal.

The valid range for a normal RGB color is 0 to 16,777,215 (&HFFFFFF&).
Each color setting (property or argument) is a 4-byte integer. The high
byte of a number in this range equals 0. The lower 3 bytes, from least
to most significant byte, determine the amount of red, green, and blue,
respectively. The red, green, and blue components are each represented
by a number between 0 and 255 (&HFF).

Consequently, you can specify a color as a hexadecimal number using this
syntax:

&HBBGGRR&

The BB specifies the amount of blue, GG the amount of green, and RR the
amount of red. Each of these fragments is a two-digit hexadecimal number
from 00 to FF. The median value is 80. Thus, the following number
specifies gray, which has the median amount of all three colors:

&H808080&

Setting the most significant bit to 1 changes the meaning of the color
value: It no longer represents an RGB color, but an environment-wide
color specified through the Windows Control Panel. The values that
correspond to these system-wide colors range from &H80000000 to
&H80000015.

Note Although you can specify over 16 million different colors, not
all systems are capable of displaying them accurately. For more
information on how Windows represents colors, see "Working with 256
Colors" later in this chapter.

Using System Colors
When setting the colors of controls or forms in your application, you
can use colors specified by the operating system instead of specific
color values. If you specify system colors, when users of your
application change the values of system colors on their computers, your
application automatically reflects the user-specified color values.

Each system color has both a defined constant and a direct color
setting. The high byte of direct color settings for system colors
differs from those of normal RGB colors. For RGB colors, the high byte
equals 0 whereas for system colors the high byte equals 8. The rest of
the number refers to a particular system color. For example, the
hexadecimal number used to represent the color of an active window
caption is &H80000002&.

When you select color properties at design time with the Properties
window, selecting the System tab lets you choose system settings, which
are automatically converted into the hexadecimal value. You can also
find the defined constants for system colors in the Object Browser.

Constant Value Description
vbScrollBars 0x80000000 Scroll bar color
vbDesktop 0x80000001 Desktop color
vbActiveTitleBar 0x80000002 Color of the title bar for the active window
vbInactiveTitleBar 0x80000003 Color of the title bar for the inactive
window
vbWindowBackground 0x80000005 Window background color
vbWindowFrame 0x80000006 Window frame color
vbWindowText 0x80000008 Color of text in windows
vbTitleBarText 0x80000009 Color of text in caption, size box, and scroll
arrow
vbActiveBorder 0x8000000A Border color of active window
vbInactiveBorder 0x8000000B Border color of inactive window
vbApplicationWorkspace 0x8000000C Background color of multiple-document
interface (MDI) applications
vbHighlight 0x8000000D Background color of items selected in a control
vbHighlightText 0x8000000E Text color of items selected in a control
vbButtonFace 0x8000000F Color of shading on the face of command buttons
buttons
vbGrayText 0x80000011 Grayed (disabled) text
vbButtonText 0x80000012 Text color on push buttons
vbInactiveCaptionText 0x80000013 Color of text in an inactive caption
vb3DHighlight 0x80000014 Highlight color for 3-D display elements
vb3DLight 0x80000016 Second lightest 3-D color after vb3DHighlight
vbInfoText 0x80000017 Color of text in ToolTips
vbInfoBackground 0x80000018 Background color of ToolTips

--
HTH
Stephen Lebans
http://www.lebans.com
Access Code, Tips and Tricks
Please respond only to the newsgroups so everyone can benefit.

Douglas J. Steele said:
The colour value is actually RGB, but in the reverse order. If you convert
any value back to Hex, you'll see that the first 2 digits are the Blue
value, the middle 2 digits are the Green value and the last 2 digits are the
Red value.

Therefore, the following will work:

Function Red(ColourValue As Long) As Long
Dim strHexColour As String

strHexColour = Right\$("000000" & Hex(ColourValue), 6)
Red = CLng("&H" & Right\$(strHexColour, 2))

End Function

Function Green(ColourValue As Long) As Long
Dim strHexColour As String

strHexColour = Right\$("000000" & Hex(ColourValue), 6)
Green = CLng("&H" & Mid\$(strHexColour, 3, 2))

End Function

Function Blue(ColourValue As Long) As Long
Dim strHexColour As String

strHexColour = Right\$("000000" & Hex(ColourValue), 6)
Blue = CLng("&H" & Left\$(strHexColour, 2))

End Function

--
Doug Steele, Microsoft Access MVP

message news:[email protected]...

Show off! <g>

Hi
Are there functions that can split a colour value into its component rgb
If I give
colour = RGB ( 255,0,0)
I would like
red (colour) returns 255
green (colour) ..... 0

Cheers

--
Andrew Black
London

Andrew,
my starting-point was to automatically change the font-colour, based on a table in Excel
(2 columns in 'Sheet2')
1139 (255, 0, 255)
1189 (255, 255, 0)
1710 (0, 0, 255) etc.

This functions as a LOOKUP-Table.
I wrote a FUNCTION (ChangeRGB)
As a result you obtain three variables: Red, Green and Blue, containing
the elements of the RGB-string. The "(" and ")" first have to be removed from
the initial RGB-string.
Then you use the SPLIT-command to attack the array variables.
Since the RGB-string always consists of only three elements, the number of
"IF" statements = 3 (from 0 to 2).
If you need more information, let me know and I will send you the Excel-file

Greetings from Holland.
Jouke de Vries

I hope you can comprehend the code:

Function ChangeRGB(Rcell As Range)
Dim vRGBCode As String
Dim strArray() As String
Dim intCount As Integer
Dim Red As String
Dim Green As String
Dim Blue As String
Dim intRed As Integer
Dim intGreen As Integer
Dim intBlue As Integer
Dim strColor As String
intRed = -1
intGreen = -1
intBlue = -1
vRGBCode = WorksheetFunction.VLookup(Rcell, Worksheets("Sheet2").Range("\$A:\$B"), 2, False)
vRGBCode = Replace(vRGBCode, "(", "")
vRGBCode = Replace(vRGBCode, ")", "")
strArray = Split(vRGBCode, ",")

For intCount = LBound(strArray) To UBound(strArray)
If intCount = 0 Then
Red = Trim(strArray(intCount))
End If
If intCount = 1 Then
Green = Trim(strArray(intCount))
End If
If intCount = 2 Then
Blue = Trim(strArray(intCount))
End If
Next
Rcell.Offset(0, 1).Font.Color = RGB(Red, Green, Blue)
End Function