Extract The Red, Green and Blue Values From a Long

Category:

Screen/Graphics

Type:

Snippets

Difficulty:

Intermediate

Author:

Kirk Siqveland

Version Compatibility: Visual Basic 6

More information:

The included snippet makes it easy to extract the RGB values from a value of data type long. Everything I found on the web seems to result in slightly inaccurate numbers, so I made my own version of an unRGB function that I think is more accurate and easier to understand. The source of the original function is unknown.

Instructions: Copy the declarations and code below and paste directly into your VB project.

Declarations:
'The API call to get the current desktop's color settings. Private Declare Function GetSysColor Lib "user32.dll" (ByVal nIndex As Long) As Long

Code:

'This takes a Long Integer as a color and breaks it down into 'the Red, Green and Blue values
'
Public Sub unRGB(ByVal lSourceColor As Long, ByRef iRed As Integer, ByRef iGreen As Integer, ByRef iBlue As Integer)
Dim rgbColor As Long
Dim lGreen As Long      'This seems to be necessary to perform                                 
                        'the multiplication by &H100
    
    'First make sure we have an RGB color not a system color:
         rgbColor = GetRGBValue(lSourceColor)
    
    'Now we break it down by dividing from largest to smallest
    'and removing the values we have already calculated
        iBlue = Int(rgbColor / &H10000) 'Easier to read in hex
            rgbColor = rgbColor - (iBlue * &H10000)
        iGreen = Int(rgbColor / &H100)
            lGreen = iGreen
        iRed = rgbColor - (lGreen * &H100)
    'That's it.
End Sub

'This take a long integer which might be a system color or an RGB
'and returns the RGB long integer
Public Function GetRGBValue(Color As Long) As Long
    If (Color And &H80000000) Then  ' This is a system color
        Color = Color And &HFF&     ' Get the color index
        ' Get the RGB value
             GetRGBValue = GetSysColor(Color)
    Else
        'Not a system color
             GetRGBValue = Color
    End If
End Function