Class: RailsDataExplorer::Chart::HistogramCategorical

Inherits:
RailsDataExplorer::Chart show all
Defined in:
lib/rails-data-explorer/chart/histogram_categorical.rb

Instance Attribute Summary

Attributes inherited from RailsDataExplorer::Chart

#output_buffer

Instance Method Summary collapse

Methods inherited from RailsDataExplorer::Chart

#dom_id

Constructor Details

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

Returns a new instance of HistogramCategorical.



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# File 'lib/rails-data-explorer/chart/histogram_categorical.rb', line 5

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_categorical.rb', line 10

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

  # compute histogram
  h = x_ds.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 }
    }.sort(
      &x_ds.label_sorter(
        :x,
        lambda { |a,b| b[:y] <=> a[:y] }
      )
    ),
    x_axis_label: x_ds.name,
    x_axis_tick_format: "d3.format('r')",
    y_axis_label: 'Frequency',
    y_axis_tick_format: "d3.format(',g')", #histogram_values_ds.axis_tick_format,
    y_scale_type: y_scale_type,
    y_scale_domain: [bar_y2_val, histogram_values_ds.max_val],
    bar_y2_val: bar_y2_val,
  }
end

#render ⇒ Object 



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# File 'lib/rails-data-explorer/chart/histogram_categorical.rb', line 38

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

#render? ⇒ Boolean

Render HistogramCategorical only if there is a fairly small number of distinct values.

Returns:

  • (Boolean) 


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# File 'lib/rails-data-explorer/chart/histogram_categorical.rb', line 174

def render?
  !@data_set.data_series.first.has_many_uniq_vals?
end

#render_nvd3(ca) ⇒ Object 



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# File 'lib/rails-data-explorer/chart/histogram_categorical.rb', line 120

def render_nvd3(ca)
  %(
    <div class="rde-chart rde-histogram-categorical">
      <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.discreteBarChart()
              ;

            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>' + x + '</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/histogram_categorical.rb', line 45

def render_vega(ca)
  %(
    <div class="rde-chart rde-histogram-categorical">
      <h3 class="rde-chart-title">Histogram</h3>
      <div id="#{ dom_id }"></div>
      <script type="text/javascript">
        (function() {
          var spec = {
            "width": 800,
            "height": 200,
            "padding": {"top": 10, "left": 70, "bottom": 50, "right": 10},
            "data": [
              {
                "name": "table",
                "values": #{ ca[:values].to_json }
              }
            ],
            "scales": [
              {
                "name": "x",
                "type": "ordinal",
                "range": "width",
                "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": {"scale": "x", "band": true, "offset": -1},
                    "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