ConvertLayersToGrayscale.rvb

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' ConvertLayersToGrayscale.rvb -- November 2015
' If this code works, it was written by Dale Fugier.
' If not, I don't know who wrote it.
' Works with Rhino 5.
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Option Explicit
 
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' Converts the colors of layers to grayscale
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Sub ConvertLayersToGrayscale()
 
	Dim arrLayers, strLayer, lngColor, nAlgorithm
	Dim nGray, nRed, nGreen, nBlue
	Dim arrAlgorithms, strAlgorithm
	
	arrAlgorithms = Array("Average", "BT601", "BT709", "Desaturate", "Luminance", "NTSC")
	strAlgorithm = Rhino.ListBox(arrAlgorithms, "Select a grayscale algorithm", "Layer Color")
	If IsNull(strAlgorithm) Then Exit Sub
 
	Call Rhino.EnableRedraw(False)
 
	arrLayers = Rhino.LayerNames
	For Each strLayer In arrLayers
 
		lngColor = Rhino.LayerColor(strLayer)
		nRed = Rhino.ColorRedValue(lngColor)
		nGreen = Rhino.ColorGreenValue(lngColor)
		nBlue = Rhino.ColorBlueValue(lngColor)
 
		If strAlgorithm = "Average" Then
			nGray = Average(nRed, nGreen, nBlue)
		ElseIf strAlgorithm = "BT601" Then
			nGray = BT601(nRed, nGreen, nBlue)
		ElseIf strAlgorithm = "BT709" Then
			nGray = BT709(nRed, nGreen, nBlue)
		ElseIf strAlgorithm = "Desaturate" Then
			nGray = Desaturate(nRed, nGreen, nBlue)
		ElseIf strAlgorithm = "Luminance" Then
			nGray = Luminance(nRed, nGreen, nBlue)
		Else
			nGray = NTSC(nRed, nGreen, nBlue)
		End If	
		
		Call Rhino.LayerColor(strlayer, RGB(nGray, nGray, nGray))
 
	Next
 
	Call Rhino.EnableRedraw(True)
 
End Sub

Function Average(nRed, nGreen, nBlue)
	Dim nGray
	nGray = (nRed + nGreen + nBlue) / 3
	Average = CInt(nGray)
End Function

Function BT601(nRed, nGreen, nBlue)
	Dim nGray
	nGray = (nRed * 0.299) + (nGreen * 0.587) + (nBlue * 0.114)
	BT601 = CInt(nGray)
End Function

Function BT709(nRed, nGreen, nBlue)
	Dim nGray
	nGray = (nRed * 0.2126) + (nGreen * 0.7152) + (nBlue * 0.0722)
	BT709 = CInt(nGray)
End Function

Function Desaturate(nRed, nGreen, nBlue)
	Dim nGray
	nGray = (Rhino.Max(Array(nRed, nGreen, nBlue)) + Rhino.Min(Array(nRed, nGreen, nBlue))) / 2
	Desaturate = CInt(nGray)
End Function

Function Luminance(nRed, nGreen, nBlue)
	Dim nGray
	nGray = (nRed * 0.21) + (nGreen * 0.72) + (nBlue * 0.07)
	Luminance = CInt(nGray)
End Function

Function NTSC(nRed, nGreen, nBlue)
	Dim nGray
	nGray = (nRed * 0.3) + (nGreen * 0.59) + (nBlue * 0.11)
	NTSC = CInt(nGray)
End Function

ConvertLayersToGrayscale