Stamp

--c := a + 2*b - 256;
--if c < 0 then
--  result := 0
--else if c > 255 then
--  result := 255
--else
--  result := c;
-- ******* stamp mode *************
on stampBlendMode (image1, image2)
 
  theWidth = image1.width - 1
  theHeight = image1.height - 1
  theImage = image(theWidth + 1, theHeight + 1, 32)
 
  repeat with x = 0 to theWidth
    repeat with y = 0 to theHeight
      theColour1 = image1.getPixel(point(x,y))
      theColour2 = image2.getPixel(point(x,y))
      theNewColour = color(0,0,0)
 
      theNewColour.red = max(min(theColour1.red + (2 * theColour2.red) - 256, 255), 0)
      theNewColour.green = max(min(theColour1.green + (2 * theColour2.green) - 256, 255), 0)
      theNewColour.blue = max(min(theColour1.blue + (2 * theColour2.blue) - 256, 255), 0)
 
      theImage.setPixel(point(x, y), theNewColour)
 
    end repeat
  end repeat
  return theImage
end