# File lib/gruff/base.rb, line 204
    def initialize_ivars
      # Internal for calculations
      @raw_columns = 800.0
      @raw_rows = 800.0 * (@rows/@columns)
      @column_count = 0
      @marker_count = nil
      @maximum_value = @minimum_value = nil
      @has_data = false
      @data = Array.new
      @labels = Hash.new
      @labels_seen = Hash.new
      @sort = true
      @title = nil

      @scale = @columns / @raw_columns

      vera_font_path = File.expand_path('Vera.ttf', ENV['MAGICK_FONT_PATH'])
      @font = File.exists?(vera_font_path) ? vera_font_path : nil

      @marker_font_size = 21.0
      @legend_font_size = 20.0
      @title_font_size = 36.0
      
      @top_margin = @bottom_margin = @left_margin = @right_margin = DEFAULT_MARGIN
      @legend_margin = LEGEND_MARGIN
      @title_margin = TITLE_MARGIN

      @legend_box_size = 20.0

      @no_data_message = "No Data"

      @hide_line_markers = @hide_legend = @hide_title = @hide_line_numbers = false
      @center_labels_over_point = true
      @has_left_labels = false

      @additional_line_values = []
      @additional_line_colors = []
      @theme_options = {}

      @x_axis_label = @y_axis_label = nil
      @y_axis_increment = nil
      @stacked = nil
      @norm_data = nil
    end