     if currentRow <= lastRow
       @drawLines(context, currentRow, lastRow, currentRow-firstRow)
 
+  # Computes the ranges that are not affected by the current pending changes.
+  #
+  # firstRow - The first visible row index {Number}.
+  # lastRow - The last visible row index {Number}.
+  #
+  # Returns an {Array} of ranges.
   computeIntactRanges: (firstRow, lastRow) ->
     return [] if !@offscreenFirstRow? and !@offscreenLastRow?
 

  #    ##    ##  ##     ## ##   ### ##    ##  ##       ##    ##
  #    ##     ## ##     ## ##    ##  ######   ########  ######

  fillGapsBetweenIntactRanges: (context, intactRanges, firstRow, lastRow) ->
    currentRow = firstRow
    # intactRanges is sorted, we can safely fill between ranges


  # Internal: Draws a single token on the given context.
  #
  # context - The canvas context object onto which draw the token.
  # text - The {String} text of the token.
  # color - The {String} color of the token.
  # x - The {Number} position on the x axis at which render the token.
