Class: RailsDataExplorer::Chart::HistogramQuantitative

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

Overview

Responsibilities:

* Render a histogram for univariate analysis of a quantitative data series.

Collaborators:

* DataSet

Direct Known Subclasses

HistogramTemporal

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 = {}) ⇒ HistogramQuantitative

Returns a new instance of HistogramQuantitative.



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

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

  # compute histogram
  quantizer = Utils::DataQuantizer.new(x_ds, max_number_of_bins: 100)
  quantized_values = quantizer.values
  number_of_bars = quantizer.number_of_bins
  width = 960
  h = quantized_values.inject(Hash.new(0)) { |m,e| m[e] += 1; m }
  histogram_values_ds = DataSeries.new('_', h.values)
  y_scale_type = histogram_values_ds.axis_scale(:vega)
  bar_y2_val = 'log' == y_scale_type ? histogram_values_ds.min_val / 10.0 : 0
  {
    values: h.map { |k,v| { x: k, y: v } },
    width: width,
    x_axis_label: x_ds.name,
    x_axis_tick_format: x_ds.axis_tick_format,
    x_scale_type: 'linear',
    x_scale_nice: true,
    bar_width: (width / number_of_bars.to_f) - 3,
    y_axis_label: 'Frequency',
    y_axis_tick_format: "d3.format('r')",
    y_scale_type: y_scale_type,
    y_scale_domain: [bar_y2_val, histogram_values_ds.max_val],
    bar_y2_val: bar_y2_val,
    css_class: 'rde-histogram-quantitative',
  }
end

#render ⇒ Object 



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# File 'lib/rails_data_explorer/chart/histogram_quantitative.rb', line 49

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/histogram_quantitative.rb', line 133

def render_nvd3(ca)
  %(
    <div class="rde-chart rde-histogram-quantitative">
      <h3 class="rde-chart-title">Histogram</h3>
      <div id="#{ dom_id }", style="height: 200px;">
        <svg></svg>
      </div>
      <script type="text/javascript">
        (function() {
          var data = [
            {
              values: #{ ca[:values].to_json },
              key: '#{ ca[:x_axis_label] }'
            }
          ];

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

            chart.xAxis
              .axisLabel('#{ ca[:x_axis_label] }')
              .tickFormat(#{ ca[:x_axis_tick_format] })
              ;

            chart.yAxis
              .axisLabel('#{ ca[:y_axis_label] }')
              .tickFormat(#{ ca[:y_axis_tick_format] })
              ;

            chart.tooltipContent(
              function(key, x, y, e, graph) {
                return '<p>' + key + '</p>' + '<p>' +  y + ' at ' + x + '</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/histogram_quantitative.rb', line 56

def render_vega(ca)
  %(
    <div class="rde-chart #{ ca[:css_class] }">
      <h3 class="rde-chart-title">Histogram</h3>
      <div id="#{ dom_id }"></div>
      <script type="text/javascript">
        (function() {
          var spec = {
            "width": #{ ca[:width] },
            "height": 200,
            "padding": {"top": 10, "left": 70, "bottom": 50, "right": 10},
            "data": [
              {
                "name": "table",
                "values": #{ ca[:values].to_json },
              }
            ],
            "scales": [
              {
                "name": "x",
                "type": "#{ ca[:x_scale_type] }",
                "range": "width",
                "zero": false,
                "nice": #{ ca[:x_scale_nice] },
                "domain": {"data": "table", "field": "data.x"},
              },
              {
                "name": "y",
                "type": "#{ ca[:y_scale_type] }",
                "range": "height",
                "domain": #{ ca[:y_scale_domain].to_json },
              }
            ],
            "axes": [
              {
                "type": "x",
                "scale": "x",
                "title": "#{ ca[:x_axis_label] }",
                "format": #{ ca[:x_axis_tick_format] },
              },
              {
                "type": "y",
                "scale": "y",
                "title": "#{ ca[:y_axis_label] }",
                "titleOffset": 60,
                "format": #{ ca[:y_axis_tick_format] },
              }
            ],
            "marks": [
              {
                "type": "rect",
                "from": {"data": "table"},
                "properties": {
                  "enter": {
                    "x": {"scale": "x", "field": "data.x"},
                    "width": { "value": #{ ca[:bar_width] } },
                    "y": {"scale": "y", "field": "data.y"},
                    "y2": {"scale": "y", "value": #{ ca[:bar_y2_val] }},
                  },
                  "update": {
                    "fill": {"value": "#1F77B4"}
                  },
                }
              }
            ]
          };

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

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