Class: Charting::Highcharts::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/ar_to_chart/charting/highcharts/base.rb

Overview

Base class for chart renderers. Chart renderers should subclass rather than instantiate Base directly.

Direct Known Subclasses

Area, Pie

Constant Summary collapse

WEEKEND =

The days of the week that are the weekend (Sun, Sat)

[0,6]
AXIS_START_UNIT =

Where highcharts starts its x-axis in axis units

0.5
MAX_X_LABELS =

Display no more than this number of category labels

10
DEFAULT_OPTIONS = 
{

}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data_source, category_column, data_columns, options = {}) ⇒ Base

Initialize a new chart.

Parameters

data_source:      Array of ActiveRecord objects for rendering as a chart
category_column:  The name of the column which is the category (X) axis
data_columns:     The name (or array of names) of the columns which are
                  the data series.
options:          Options hash

Options

title:            Chart title (default: none)
subtitle:         Subtitle (default: none)
x_axis_title:     X-Axis title (default: none)
y_axis_title:     Y-Axis title (defualt: none)
x_step:           X-Axis labels are printed every 'x' steps
                  Requires Highcharts beta 2.1
x_plot_bands:     Plot bands in Ruby Hash format according to the
                  Highcharts documented format
linearize:        Linearize the data to ensure continuous
                  series on the X-Axis.
weekend_plot_bands:   Creates plot-bands for the weekends (Saturday/Sunday)
container:        DOM id for the container div.  Default is to generate one.



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 40

def initialize(data_source, category_column, data_columns, options = {})
  @options          = DEFAULT_OPTIONS.merge(options)
  @category_column  = category_column
  @data_columns     = data_columns
  @data_source      = data_source
  @data_source      = linearize if @options.delete(:linearize)       
  @options[:x_step] ||= (@data_source.size.to_f / MAX_X_LABELS.to_f).round
end

Instance Attribute Details

#category_column ⇒ Object (readonly)

Returns the value of attribute category_column.



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 6

def category_column
  @category_column
end

#data_columns ⇒ Object (readonly)

Returns the value of attribute data_columns.



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 6

def data_columns
  @data_columns
end

#data_source ⇒ Object (readonly)

Returns the value of attribute data_source.



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 6

def data_source
  @data_source
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 6

def options
  @options
end

Instance Method Details

#categories ⇒ Object

Define in concrete subclass



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 66

def categories
  nil
end

#chart_options ⇒ Object 



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 49

def chart_options
  {
    :title        => options[:title],
    :subtitle     => options[:subtitle],
    :x_axis       => options[:x_axis_title], 
    :y_axis       => options[:y_axis_title], 
    :x_step       => options[:x_step],
    :x_plot_bands => weekend_plot_bands
  }
end

#chart_type ⇒ Object 



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 86

def chart_type
  @chart_type ||= self.class.name.split('::').last.downcase
end

#container ⇒ Object 



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 90

def container
  options[:container]
end

#linearize ⇒ Object

When we retrieve datat from the data base it may have gaps where not results are available. For charting we want to have a linearized series of data so here we plug the gaps.

Punt that the categeory column tells us enough to know what the data should be.



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 110

def linearize
  return data_source unless range = Charting::Period.range_from(options)
  range = data_source.first[category_column]..range.last if range.first > data_source.first[category_column]
  klass = data_source.first.class
  index = 0
  range.inject(Array.new) do |linear_data, data_point|
    if data_source[index] && data_source[index][category_column] == data_point
      linear_data << data_source[index]
      index += 1
    else
      new_row = klass.new(category_column => data_point)
      data_columns.each {|column| new_row[column] = 0 }
      yield new_row if block_given?
      linear_data << new_row
    end
    linear_data
  end
end

#series ⇒ Object

Define in concrete subclass



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 61

def series
  nil
end

#series_name(column) ⇒ Object 



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 82

def series_name(column)
  data_source.first.class.human_attribute_name(column)
end

#to_js ⇒ Object 



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 94

def to_js
  "    chart.\#{chart_type}('\#{container}', \n      \#{categories.to_json}, \n      \#{series.to_json},\n      \#{chart_options.to_json}\n    );\n  EOF\nend\n"

#weekend_plot_bands ⇒ Object

Returns a plotbands definition for the data source Only if the category column is a date or datetime



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# File 'lib/ar_to_chart/charting/highcharts/base.rb', line 72

def weekend_plot_bands
  return unless options[:weekend_plot_bands] && data_source.first[category_column].respond_to?(:to_date)
  x_plot_bands = data_source.inject_with_index([]) do |plot_bands, row, index|
    if WEEKEND.include?(row[category_column].to_date.wday)
      plot_bands << {:from => (index + AXIS_START_UNIT - 1), :to => (index + AXIS_START_UNIT)}
    end
    plot_bands
  end
end