       s: zero new Array 101 # [0.0, 1.0] -> [0, 101]
       c: zero new Array 135 # https://github.com/gka/chroma.js/issues/63
       l: zero new Array 101 # [0.0, 1.0] -> [0, 101]
-    computeHistogram imageData.data, result, ->
+    computeHistogram imageData.data, result, c.params.step, ->
       outPorts.histogram.send result
       do callback


  c.inPorts.add 'canvas',
    datatype: 'object'
  c.outPorts.add 'histogram',
    datatype: 'object'
  c.outPorts.add 'error',


  noflo.helpers.WirePattern c,
    in: ['canvas']
    params: ['step']
    out: ['histogram', 'error']
    forwardGroups: true
    async: true
