Class: Gruff::Bar

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

Overview

Gruff::Bar provide a bar graph that presents categorical data with rectangular bars.

Here’s how to set up a Gruff::Bar.

g = Gruff::Bar.new
g.title = 'Bar Graph With Manual Colors'
g.spacing_factor = 0.1
g.group_spacing = 20
g.data :Art, [0, 5, 8, 15], '#990000'
g.data :Philosophy, [10, 3, 2, 8], '#009900'
g.data :Science, [2, 15, 8, 11], '#990099'
g.write('bar.png')

Direct Known Subclasses

Histogram, Mini::Bar

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 collapse

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

Constructor Details

This class inherits a constructor from Gruff::Base

Instance Attribute Details

#bar_spacing=(value) ⇒ Object (writeonly)

Spacing factor applied between bars.



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# File 'lib/gruff/bar.rb', line 22

def bar_spacing=(value)
  @bar_spacing = value
end

#group_spacing=(value) ⇒ Object (writeonly)

Spacing factor applied between a group of bars belonging to the same label.



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# File 'lib/gruff/bar.rb', line 25

def group_spacing=(value)
  @group_spacing = value
end

#hide_labels=(value) ⇒ Object (writeonly)

Prevent drawing of column labels below a bar graph. Default is false.



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# File 'lib/gruff/bar.rb', line 36

def hide_labels=(value)
  @hide_labels = value
end

#label_formatting=(value) ⇒ Object (writeonly)

Set the number output format for labels using sprintf. Default is “%.2f”.



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# File 'lib/gruff/bar.rb', line 29

def label_formatting=(value)
  @label_formatting = value
end

#show_labels_for_bar_values=(value) ⇒ Object (writeonly)

Output the values for the bars on a bar graph. Default is false.



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# File 'lib/gruff/bar.rb', line 33

def show_labels_for_bar_values=(value)
  @show_labels_for_bar_values = value
end

Instance Method Details

#draw ⇒ Object 



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# File 'lib/gruff/bar.rb', line 48

def draw
  # Labels will be centered over the left of the bar if
  # there are more labels than columns. This is basically the same
  # as where it would be for a line graph.
  @center_labels_over_point = (@labels.keys.length > column_count)

  super
  return unless data_given?

  draw_bars
end

#spacing_factor=(space_percent) ⇒ Object

Can be used to adjust the spaces between the bars. Accepts values between 0.00 and 1.00 where 0.00 means no spacing at all and 1 means that each bars’ width is nearly 0 (so each bar is a simple line with no x dimension).

Default value is 0.9.

Raises:

  • (ArgumentError) 


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# File 'lib/gruff/bar.rb', line 66

def spacing_factor=(space_percent)
  raise ArgumentError, 'spacing_factor must be between 0.00 and 1.00' unless (space_percent >= 0) && (space_percent <= 1)

  @spacing_factor = (1 - space_percent)
end