Class: RailsDataExplorer::Chart::PieChart

Inherits:
RailsDataExplorer::Chart show all
Defined in:
lib/rails_data_explorer/chart/pie_chart.rb

Overview

Responsibilities:

* Render a pie chart for univariate analysis of a categorical data series.

Collaborators:

* DataSet

Instance Attribute Summary

Attributes inherited from RailsDataExplorer::Chart

#output_buffer

Instance Method Summary collapse

Methods inherited from RailsDataExplorer::Chart

#dom_id, #render?

Constructor Details

#initialize(_data_set, options = {}) ⇒ PieChart

Returns a new instance of PieChart.



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# File 'lib/rails_data_explorer/chart/pie_chart.rb', line 14

def initialize(_data_set, options = {})
  @data_set = _data_set
  @options = {}.merge(options)
end

Instance Method Details

#compute_chart_attrs ⇒ Object 



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# File 'lib/rails_data_explorer/chart/pie_chart.rb', line 19

def compute_chart_attrs
  x_ds = @data_set.data_series.first
  return false  if x_ds.nil?

  val_mod = { name: :limit_distinct_values }
  total_count = x_ds.values(val_mod).length
  # compute histogram
  h = x_ds.values(val_mod).inject(Hash.new(0)) { |m,e| m[e] += 1; m }
  {
    values: h.map { |k,v|
      { key: k, value: (v / total_count.to_f) }
    }.sort(
      &x_ds.label_sorter(
        :key,
        lambda { |a,b| b[:value] <=> a[:value] }
      )
    )
  }
end

#render ⇒ Object 



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# File 'lib/rails_data_explorer/chart/pie_chart.rb', line 39

def render
  return ''  unless render?
  ca = compute_chart_attrs
  return ''  unless ca
  render_vega(ca)
end

#render_nvd3(ca) ⇒ Object 



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# File 'lib/rails_data_explorer/chart/pie_chart.rb', line 110

def render_nvd3(ca)
  %(
    <div class="rde-chart rde-pie-chart">
      <h3 class="rde-chart-title">Pie Chart</h3>
      <div id="#{ dom_id }", style="height: 400px; width: 400px;">
        <svg></svg>
      </div>
      <script type="text/javascript">
        (function() {
          var data = #{ ca[:values].to_json };

          nv.addGraph(function() {
            var chart = nv.models.pieChart()
              ;

            chart.valueFormat(d3.format('.1%'))
                 .donut(true)
              ;
            chart.tooltipContent(
              function(key, y, e, graph) {
                return '<p>' + key + '</p>' + '<p>' +  y + '</p>'
              }
            );

            d3.select('##{ dom_id } svg')
              .datum(data)
              .transition().duration(100)
              .call(chart)
              ;

            nv.utils.windowResize(chart.update);

            return chart;
          });
        })();
      </script>
    </div>
  )
end

#render_vega(ca) ⇒ Object 



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# File 'lib/rails_data_explorer/chart/pie_chart.rb', line 46

def render_vega(ca)
  %(
    <div class="rde-chart rde-pie-chart">
      <h3 class="rde-chart-title">Pie Chart</h3>
      <div id="#{ dom_id }"></div>
      <script type="text/javascript">
        (function() {
          var spec = {
            "width": 300,
            "height": 300,
            "padding": {"top": 10, "left": 10, "bottom": 10, "right": 100},
            "data": [
              {
                "name": "table",
                "values": #{ ca[:values].to_json }
              }
            ],
            "scales": [
              {
                "name": "color",
                "domain": {"data": "table", "field": "data.key"},
                "range": "category10",
                "type": "ordinal"
              },
            ],
            "axes": [],
            "marks": [
              {
                "type": "arc",
                "from": {
                  "data": "table",
                  "transform": [{"type": "pie", "value": "data.value"}]
                },
                "properties": {
                  "enter": {
                    "x": {"group": "width", "mult": 0.5},
                    "y": {"group": "height", "mult": 0.5},
                    "endAngle": {"field": "endAngle"},
                    "innerRadius": {"value": 100},
                    "outerRadius": {"value": 150},
                    "startAngle": {"field": "startAngle"},
                    "stroke": {"value": "white"},
                    "fill": {"field": "data.key", "scale": "color"}
                  }
                }
              }
            ],
            "legends": [
              {
                "fill": "color",
              }
            ],
          };

          vg.parse.spec(spec, function(chart) {
            var view = chart({ el:"##{ dom_id }" }).update();
          });

        })();
      </script>
    </div>
  )
end