Crossfilter Example with d3.layout.histogram

[Max Schulze]

Hello everyone,

I'm trying to rebuild the http://square.github.com/crossfilter/ example, but using d3.layout.histogram() + crossfilter to generate the data. I have some issues understanding what I have to change to make it work. I've already changed the scales but the resizePath method is not quite clear to me (and how the bars are drawn):

barPath = (groups) ->
  path = []
  i = -1
  n = groups.length
          
  while ++i < n
    d = groups[i]
            
    path.push("M", x(d.key), ",", height, "V", y(d.value), "h9V", height)
          
  return path.join("")
resizePath = (d) ->
  e = +(d == "e")
  x1 = e ? 1 : -1
  y1 = height / 3
          
  return "M#{(.5 * x1)},#{y1}A6,6 0 0 #{e} #{(6.5 * x1)},#{(y1 + 6)}
          V#{(2 * y1 - 6)}A6,6 0 0 #{e} #{(.5 * x1)},#{(2 * y1)}
          Z
          M#{(2.5 * x1)},#{(y1 + 8)}
          V#{(2 * y1 - 8)}
          M#{(4.5 * x1)},#{(y1 + 8)}
          V#{(2 * y1 - 8)}"

Could anyone help me understand better?

Thank you,

Max

[Mike Bostock]

There's no reason to use Crossfilter with d3.layout.histogram—they do
the same thing. Either use crossfilter to compute the bins, or you use
the histogram layout.

Mike