Class: Gruff::StackedBar

Inherits:
Base
  • Object
show all
Includes:
StackedMixin
Defined in:
lib/gruff/stacked_bar.rb

Direct Known Subclasses

AccumulatorBar

Constant Summary

Constants inherited from Base

Base::DATA_COLOR_INDEX, Base::DATA_LABEL_INDEX, Base::DATA_VALUES_INDEX, Base::DATA_VALUES_X_INDEX, Base::DEBUG, Base::DEFAULT_MARGIN, Base::DEFAULT_TARGET_WIDTH, Base::LABEL_MARGIN, Base::LEGEND_MARGIN, Base::THOUSAND_SEPARATOR

Instance Attribute Summary collapse

Attributes inherited from Base

#additional_line_values, #bottom_margin, #center_labels_over_point, #colors, #font, #font_color, #has_left_labels, #hide_legend, #hide_line_markers, #hide_line_numbers, #hide_title, #labels, #left_margin, #legend_box_size, #legend_font_size, #legend_margin, #marker_color, #marker_count, #marker_font_size, #maximum_value, #minimum_value, #no_data_message, #right_margin, #sort, #stacked, #title, #title_font_size, #title_margin, #top_margin, #x_axis_label, #y_axis_increment, #y_axis_label

Instance Method Summary collapse

Methods inherited from Base

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

Methods included from Deprecated

#graph_height, #graph_left, #graph_top, #graph_width, #scale_measurements, #total_height

Constructor Details

This class inherits a constructor from Gruff::Base

Instance Attribute Details

#bar_spacing ⇒ Object

Spacing factor applied between bars



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# File 'lib/gruff/stacked_bar.rb', line 9

def bar_spacing
  @bar_spacing
end

Instance Method Details

#draw ⇒ Object

Draws a bar graph, but multiple sets are stacked on top of each other.



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# File 'lib/gruff/stacked_bar.rb', line 12

def draw
  get_maximum_by_stack
  super
  return unless @has_data

  # Setup spacing.
  #
  # Columns sit stacked.
  @bar_spacing ||= 0.9
  @bar_width = @graph_width / @column_count.to_f
  padding = (@bar_width * (1 - @bar_spacing)) / 2

  @d = @d.stroke_opacity 0.0
  
  height = Array.new(@column_count, 0)

  @norm_data.each_with_index do |data_row, row_index|      
    data_row[DATA_VALUES_INDEX].each_with_index do |data_point, point_index|
      @d = @d.fill data_row[DATA_COLOR_INDEX]
      
      # Calculate center based on bar_width and current row
      label_center = @graph_left + (@bar_width * point_index) + (@bar_width * @bar_spacing / 2.0)
      draw_label(label_center, point_index)

      next if (data_point == 0)
      # Use incremented x and scaled y
      left_x = @graph_left + (@bar_width * point_index) + padding
      left_y = @graph_top + (@graph_height -
                             data_point * @graph_height - 
                             height[point_index]) + 1
      right_x = left_x + @bar_width * @bar_spacing
      right_y = @graph_top + @graph_height - height[point_index] - 1
      
      # update the total height of the current stacked bar
      height[point_index] += (data_point * @graph_height ) 
      
      @d = @d.rectangle(left_x, left_y, right_x, right_y)
      
    end

  end

  @d.draw(@base_image)    
end