Class: Gruff::Bullet

Inherits:
Base
  • Object
show all
Defined in:
lib/gruff/bullet.rb

Overview

A bullet graph is a variation of a bar graph. en.wikipedia.org/wiki/Bullet_graph

Here’s how to set up a Gruff::Bullet.

g = Gruff::Bullet.new
g.title = 'Monthly Revenue'
g.data 75, 100, { target: 80, low: 50, high: 90 }
g.write('bullet.png')

Constant Summary

Constants inherited from Base

Gruff::Base::DEFAULT_MARGIN, Gruff::Base::DEFAULT_TARGET_WIDTH, Gruff::Base::LABEL_MARGIN, Gruff::Base::LEGEND_MARGIN

Instance Attribute Summary

Attributes inherited from Base

#bold_title, #bottom_margin, #center_labels_over_point, #colors, #font_color, #has_left_labels, #hide_legend, #hide_line_markers, #hide_line_numbers, #hide_title, #label_max_size, #label_stagger_height, #label_truncation_style, #labels, #left_margin, #legend_at_bottom, #legend_box_size, #legend_font_size, #legend_margin, #marker_color, #marker_font_size, #marker_shadow_color, #maximum_value, #minimum_value, #no_data_message, #right_margin, #sort, #sorted_drawing, #title, #title_font, #title_font_size, #title_margin, #top_margin, #use_data_label, #x_axis_increment, #x_axis_label, #y_axis_increment, #y_axis_label

Instance Method Summary collapse

Methods inherited from Base

#add_color, #font=, #margins=, #replace_colors, #theme=, #theme_37signals, #theme_greyscale, #theme_keynote, #theme_odeo, #theme_pastel, #theme_rails_keynote, #to_blob, #to_image, #write

Constructor Details

#initialize(target_width = '400x40') ⇒ Bullet

Returns a new instance of Bullet.



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# File 'lib/gruff/bullet.rb', line 15

def initialize(target_width = '400x40')
  super

  if target_width.is_a?(String)
    @columns, @rows = target_width.split('x').map(&:to_f)
  else
    @columns = target_width.to_f
    @rows = target_width.to_f / 5.0
  end
  @columns.freeze
  @rows.freeze

  self.theme = Gruff::Themes::GREYSCALE
end

Instance Method Details

#data(value, maximum_value, options = {}) ⇒ Object 



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# File 'lib/gruff/bullet.rb', line 37

def data(value, maximum_value, options = {})
  @value = value.to_f
  self.maximum_value = maximum_value.to_f
  @options = options
  @options.map { |k, v| @options[k] = v.to_f if v.is_a?(Numeric) }
end

#draw ⇒ Object 



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# File 'lib/gruff/bullet.rb', line 44

def draw
  # TODO: Left label
  # TODO Bottom labels and markers
  # @graph_bottom
  # Calculations are off 800x???

  @colors.reverse!

  draw_title

  title_width  = calculate_width(@title_font_size, @title)
  margin       = 30.0
  thickness    = @raw_rows / 6.0
  right_margin = margin
  graph_left   = [title_width * 1.3, margin].max
  graph_width  = @raw_columns - graph_left - right_margin
  graph_height = thickness * 3.0

  # Background
  rect_renderer = Gruff::Renderer::Rectangle.new(color: @colors[0])
  rect_renderer.render(graph_left, 0, graph_left + graph_width, graph_height)

  [:high, :low].each_with_index do |indicator, index|
    next unless @options.key?(indicator)

    indicator_width_x = graph_left + graph_width * (@options[indicator] / maximum_value)

    rect_renderer = Gruff::Renderer::Rectangle.new(color: @colors[index + 1])
    rect_renderer.render(graph_left, 0, indicator_width_x, graph_height)
  end

  if @options.key?(:target)
    target_x = graph_left + graph_width * (@options[:target] / maximum_value)
    half_thickness = thickness / 2.0

    rect_renderer = Gruff::Renderer::Rectangle.new(color: @font_color)
    rect_renderer.render(target_x, half_thickness, target_x + half_thickness, thickness * 2 + half_thickness)
  end

  # Value
  rect_renderer = Gruff::Renderer::Rectangle.new(color: @font_color)
  rect_renderer.render(graph_left, thickness, graph_left + graph_width * (@value / maximum_value), thickness * 2)
end