Class: Gruff::Area

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

Overview

Gruff::Area provides an area graph which displays graphically quantitative data.

Here’s how to set up a Gruff::Area.

g = Gruff::Area.new
g.title = 'Area Graph'
g.data :Jimmy, [25, 36, 86, 39, 25, 31, 79, 88]
g.data :Charles, [80, 54, 67, 54, 68, 70, 90, 95]
g.data :Julie, [22, 29, 35, 38, 36, 40, 46, 57]
g.write('area.png')

Constant Summary

Constants inherited from Base

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

Instance Attribute Summary collapse

Attributes inherited from Base

#bold_title, #bottom_margin, #center_labels_over_point, #colors, #font, #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_count, #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, #initialize, #margins=, #replace_colors, #theme=, #theme_37signals, #theme_greyscale, #theme_keynote, #theme_odeo, #theme_pastel, #theme_rails_keynote, #to_blob, #write

Constructor Details

This class inherits a constructor from Gruff::Base

Instance Attribute Details

#fill_opacity ⇒ Object

Specifies the filling opacity in area graph. Default is 0.85.



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# File 'lib/gruff/area.rb', line 20

def fill_opacity
  @fill_opacity
end

#stroke_width ⇒ Object

Specifies the stroke width in line around area graph. Default is 2.0.



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# File 'lib/gruff/area.rb', line 23

def stroke_width
  @stroke_width
end

Instance Method Details

#draw ⇒ Object 



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

def draw
  super

  return unless data_given?

  x_increment = @graph_width / (column_count - 1).to_f

  store.norm_data.each do |data_row|
    poly_points = []

    data_row.points.each_with_index do |data_point, index|
      # Use incremented x and scaled y
      new_x = @graph_left + (x_increment * index)
      new_y = @graph_top + (@graph_height - data_point * @graph_height)

      poly_points << new_x
      poly_points << new_y

      draw_label(new_x, index)
    end

    # Add closing points, draw polygon
    poly_points << @graph_right
    poly_points << @graph_bottom - 1
    poly_points << @graph_left
    poly_points << @graph_bottom - 1

    Gruff::Renderer::Polygon.new(color: data_row.color, width: @stroke_width, opacity: @fill_opacity).render(poly_points)
  end

  Gruff::Renderer.finish
end