Определение цвета: белый или черный?

Option Explicit
Private Declare Function GetSysColor Lib "user32" (ByVal nIndex As Long) As Long
 
Private Sub Form_Click()
    Dim C As Long, R As Byte, G As Byte, B As Byte
    C = Me.BackColor
    SplitRGB C, R, G, B
    TextBox1.BackColor = RGB(255 - R, 255 - G, 255 - B)
End Sub
 
Sub SplitRGB(ByVal Color As Long, R As Byte, G As Byte, B As Byte)
    If Color And &H80000000 Then
        Color = GetSysColor(Color And &HFF)
    End If
    R = Color And 255
    Color = Color  256
    G = Color And 255
    B = Color  256
End Sub

Option Explicit
 
Private Declare Function GetSysColor Lib "user32" (ByVal nIndex As Long) As Long
 
Private Sub Command1_Click()
    Dim C As Long, R As Integer, G As Integer, B As Integer
    
    C = Me.BackColor
    SplitRGB C, R, G, B
           '381= (3 x 127)
    If R + G + B > 381 Then
        Text1.BackColor = vbBlack
    Else
        Text1.BackColor = vbWhite
    End If
 
End Sub
 
 
 
Sub SplitRGB(ByVal Color As Long, R As Integer, G As Integer, B As Integer)
    If Color And &H80000000 Then
        Color = GetSysColor(Color And &HFF)
    End If
    R = Color And 255
    Color = Color  256
    G = Color And 255
    B = Color  256
End Sub

Option Explicit
 
Public Type RGB
    R As Byte
    G As Byte
    B As Byte
End Type
 
Public Type HSL
    H As Double
    S As Double
    L As Double
End Type
 
Public Function HSL2RGB(pHSL As HSL) As RGB
 
  Dim dTmp1   As Double
  Dim dTmp2   As Double
  Dim dTmp(2) As Double
  
  Dim i As Byte
  
  Dim RGB As RGB
  
  'make sure the HSL values are valid
    If 0 > pHSL.H Or pHSL.H > 1 Or _
       0 > pHSL.S Or pHSL.S > 1 Or _
       0 > pHSL.L Or pHSL.L > 1 Then MsgBox "HSL values are not valid!", _
                                     vbOKOnly, "Error": Exit Function
    
    If pHSL.S = 0 Then 'the color is gray (all RGB values are equal)
    
      'and they are extracted from the Luminosity
        RGB.R = CByte(255 * pHSL.L)
        RGB.G = RGB.R
        RGB.B = RGB.R
        
    Else
    
        If pHSL.L < 0.5 Then
            dTmp2 = pHSL.L * (pHSL.S + 1)
        Else
            dTmp2 = (pHSL.L + pHSL.S) - (pHSL.L * pHSL.S)
        End If
        
        dTmp1 = (2 * pHSL.L) - dTmp2
        
      'calculate each color from the Hue value
        
        dTmp(0) = pHSL.H - (2 / 3)
        dTmp(1) = pHSL.H
        dTmp(2) = pHSL.H - (1 / 3)
        
        For i = 0 To 2
        
            If dTmp(i) < 0 Then dTmp(i) = dTmp(i) + 1
            
            If 6 * dTmp(i) < 1 Then
                dTmp(i) = dTmp1 + 6 * dTmp(i) * (dTmp2 - dTmp1)
            ElseIf 2 * dTmp(i) < 1 Then
                dTmp(i) = dTmp2
            ElseIf 3 * dTmp(i) < 2 Then
                dTmp(i) = dTmp1 + 6 * ((2 / 3) - dTmp(i)) * (dTmp2 - dTmp1)
            Else
                dTmp(i) = dTmp1
            End If
            
        Next i
        
        RGB.R = CByte(255 * dTmp(0))
        RGB.G = CByte(255 * dTmp(1))
        RGB.B = CByte(255 * dTmp(2))
        
    End If
    
  'return the results
    HSL2RGB = RGB
    
End Function
 
Public Function RGB2HSL(pRGB As RGB) As HSL
 
  Dim Rd As Double
  Dim Gd As Double
  Dim Bd As Double
  
  Dim Max As Double
  Dim Min As Double
  Dim Dif As Double
  Dim Sum As Double
  
  Dim HSL As HSL
  
  'scale down the RGB color values to a 0-1 range
    Rd = pRGB.R / 255
    Gd = pRGB.G / 255
    Bd = pRGB.B / 255
    
  'get the strongest color
    Max = 0
    
    If Rd > Max Then Max = Rd
    If Gd > Max Then Max = Gd
    If Bd > Max Then Max = Bd
    
  'get the weakest color
    Min = 1
    
    If Rd < Min Then Min = Rd
    If Gd < Min Then Min = Gd
    If Bd < Min Then Min = Bd
    
  'calculate Luminosity
    HSL.L = (Max + Min) / 2
    
    If Max = Min Then 'the color is gray (all RGB values are equal)
    
        HSL.S = 0
        HSL.H = 0 'this is actually undefined
        
    Else
    
        Dif = (Max - Min)
        Sum = (Max + Min)
        
      'calculate Saturation
        If HSL.L > 0.5 Then
            HSL.S = Dif / Sum
        Else
            HSL.S = Dif / (2 - Sum)
        End If
        
      'calculate Hue
        Select Case Max
        Case Rd
            HSL.H = ((Gd - Bd) / Dif)
        Case Gd
            HSL.H = ((Bd - Rd) / Dif) + 2
        Case Bd
            HSL.H = ((Rd - Gd) / Dif) + 4
        End Select
        
        HSL.H = HSL.H / 6
        
        If HSL.H < 0 Then HSL.H = HSL.H + 1
        
    End If
    
  'return the results
    RGB2HSL = HSL
    
End Function