''' <summary>Umrechnung von RGB in CMYK Farbraum</summary>
    ''' <param name="red">In: Red</param>
    ''' <param name="green">In: Green</param>
    ''' <param name="blue">In: Blue</param>
    ''' <param name="cyan">Out: Cyan</param>
    ''' <param name="magenta">Out: Magenta</param>
    ''' <param name="yellow">Out Yellow</param>
    ''' <param name="key">Out: Key</param>
    Public Sub RGB2CMYK(ByVal red As Byte, green As Byte, blue As Byte, _
              ByRef cyan As Double, ByRef magenta As Double, _
              ByRef yellow As Double, ByRef key As Double)
 
        'http://www.easyrgb.com/index.php?X=MATH&H=13#text13
 
 
        cyan = 1 - (red / 255)
        magenta = 1 - (green / 255)
        yellow = 1 - (blue / 255)
 
        key = 1.0
        If cyan < key Then key = cyan
        If magenta < key Then key = magenta
        If yellow < key Then key = yellow
 
        If (key = 1.0) Then
            cyan = 0.0
            magenta = 0.0
            yellow = 0.0
        Else
            cyan = (cyan - key) / (1.0 - key)
            magenta = (magenta - key) / (1.0 - key)
            yellow = (yellow - key) / (1 - key)
        End If
    End Sub
 
 
    ''' <summary>Umrechnung von CMYK in RGB Farbraum</summary>
    ''' <param name="red">Out: Red</param>
    ''' <param name="green">Out: Green</param>
    ''' <param name="blue">Out: Blue</param>
    ''' <param name="cyan">In: Cyan</param>
    ''' <param name="magenta">In: Magenta</param>
    ''' <param name="yellow">In: Yellow</param>
    ''' <param name="key">In: Key</param>
    Public Sub CMYK2RGB(ByVal cyan As Double, ByVal magenta As Double, _
                         ByVal yellow As Double, ByVal key As Double,
                         ByRef red As Byte, ByRef green As Byte, ByRef blue As _
                           Byte)
 
        cyan = (cyan * (1.0 - key) + key)
        magenta = (magenta * (1 - key) + key)
        yellow = (yellow * (1.0 - key) + key)
 
        red = CByte((1.0 - cyan) * 255)
        green = CByte((1.0 - magenta) * 255)
        blue = CByte((1.0 - yellow) * 255)
 
    End Sub