D3 Examples - learning to use color legend from d3.legend

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<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Learning to use color legend from d3.legend</title>
    
    <script src="//cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/d3-legend/1.1.0/d3-legend.js"></script>
    <script src="colorbrewer.min.js"></script>
  </head>
  <body>
    <svg width="960" height="500"></svg>
    <script>
      var svg = d3.select("svg");
​
      // Color legend.
      var colorScale = d3.scale.quantize()
        .domain([ 1, 10 ])
        .range(colorbrewer.Blues[9]);
​
      var colorLegend = d3.legend.color()
        .labelFormat(d3.format(".0f"))
        .scale(colorScale)
        .shapePadding(5)
        .shapeWidth(50)
        .shapeHeight(20)
        .labelOffset(12);
​
      svg.append("g")
        .attr("transform", "translate(352, 60)")
        .call(colorLegend);
​
      var data = [3,8,5,2,8,9,2];
​
      
      svg.selectAll('circle')
        .data(data)
        .enter()
        .append('circle')
        .attr("r", function(d,i){return d * 2.5})
        .attr("cx", function(d,i){return i * 50 + 30})
        .attr("cy", 100)
        .attr("fill", function(d,i){return colorScale(d)});
​
    </script>
  </body>
</html>
​
    