ConvertLayersToGrayscale.rvb

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' ConvertLayersToGrayscale.rvb -- May 2010
' If this code works, it was written by Dale Fugier.
' If not, I don't know who wrote it.
' Works with Rhino 4.0.
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Option Explicit

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' Converts the colors of layers to grayscale
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Sub ConvertLayersToGrayscale()
  
  ' Declare local variables
  Dim arrLayers, strLayer, lngColor
  Dim nGray, nRed, nGreen, nBlue
  
  ' Turn off screen redrawing (for performance)
  Call Rhino.EnableRedraw(False)
  
  ' Get all of the layers in the document
  arrLayers = Rhino.LayerNames
  
  ' Process each layer one-by-one
  For Each strLayer In arrLayers
    
    ' Get the layer's color
    lngColor = Rhino.LayerColor(strLayer)
    
    ' Get the color's red-green-blue components
    nRed = Rhino.ColorRedValue(lngColor)
    nGreen = Rhino.ColorGreenValue(lngColor)
    nBlue = Rhino.ColorBlueValue(lngColor)
    
    ' Calculate the grayscale based on the NTSC color gamut
    nGray = CByte(nRed * 0.30) + CByte(nGreen * 0.59) + CByte(nBlue * 0.11)
    
    ' Modify the layer's color
    Call Rhino.LayerColor(strlayer, RGB(nGray, nGray, nGray))
    
  Next
  
  ' Turn on screen redrawing
  Call Rhino.EnableRedraw(True)
  
End Sub