renders a legend given a quantile scale of colors

renderlegend.coffee

@colorScale = d3.scale.quantile()
    .domain([0, .01, .1, .2, .3, .5, .8, 1.3, 2.1, 3.3])
    .range(@colors)


_renderLegend: ->
  # quantizes colors and adds an extra 0
  _legendData = [0].concat(@colorScale.quantiles())
  _legendData.unshift(0)

  _legendGroup = @svg
    .append('g')
    .attr('class', 'legend')
    .attr('transform', 'translate(' + (@margin/2) + ',' + (@gridHeight - @margin*2) + ')')

  _legend = _legendGroup
    .append('svg')
    .attr('height', @margin * 2)
    .attr('width', @gridWidth)

  _key = _legend.selectAll('.key')
    .data(_legendData)
    .enter().append('g')
    .attr('class', 'key')

  _key.append('rect')
    .attr('x', (d, i) => ((@gridSize * 3 * i) ) + @xTwiddle)
    .attr('y', @margin)
    .attr('width', @cellSize * 2)
    .attr('height', 10)
    .attr('class', 'hour')
    .attr('class', (d, i) => return if i == 0 then  'invalid' else 'bordered' )
    .style('fill', (d, i) => return if i == 0 or i == 1 then "#ffffff" else @colors[i]  )

  _key.append('text')
    .attr('x', (d, i) => ((@gridSize * 3 * i) ) + @xTwiddle)
    .attr('y', @margin - @yTwiddle)
    .text( (d, i) -> return if i == 0 then 'NaN' else "≤#{ (d).toString().substring(0, 4)} " )