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require 'rexml/document'

require 'SVG/Graph/BarBase'

module SVG

  module Graph

    # === Create presentation quality SVG horitonzal bar graphs easily

    # 

    # = Synopsis

    # 

    #   require 'SVG/Graph/BarHorizontal'

    #   

    #   fields = %w(Jan Feb Mar)

    #   data_sales_02 = [12, 45, 21]

    #   

    #   graph = SVG::Graph::BarHorizontal.new({

    #     :height => 500,

    #     :width => 300,

    #     :fields => fields,

    #   })

    #   

    #   graph.add_data({

    #     :data => data_sales_02,

    #     :title => 'Sales 2002',

    #   })

    #   

    #   print "Content-type: image/svg+xml\r\n\r\n"

    #   print graph.burn

    # 

    # = Description

    # 

    # This object aims to allow you to easily create high quality

    # SVG horitonzal bar graphs. You can either use the default style sheet

    # or supply your own. Either way there are many options which can

    # be configured to give you control over how the graph is

    # generated - with or without a key, data elements at each point,

    # title, subtitle etc.

    # 

    # = Examples

    # 

    # * http://germane-software.com/repositories/public/SVG/test/test.rb

    # 

    # = See also

    # 

    # * SVG::Graph::Graph

    # * SVG::Graph::Bar

    # * SVG::Graph::Line

    # * SVG::Graph::Pie

    # * SVG::Graph::Plot

    # * SVG::Graph::TimeSeries

    #

    # == Author

    #

    # Sean E. Russell <serATgermaneHYPHENsoftwareDOTcom>

    #

    # Copyright 2004 Sean E. Russell

    # This software is available under the Ruby license[LICENSE.txt]

    #

    class BarHorizontal < BarBase

      # In addition to the defaults set in BarBase::set_defaults, sets

      # [rotate_y_labels] true

      # [show_x_guidelines] true

      # [show_y_guidelines] false

      def set_defaults

        super

        init_with( 

          :rotate_y_labels    => true,

          :show_x_guidelines  => true,

          :show_y_guidelines  => false

        )

        self.right_align = self.right_font = 1

      end

      protected

      def get_x_labels

        maxvalue = max_value

        minvalue = min_value

        range = maxvalue - minvalue

        top_pad = range == 0 ? 10 : range / 20.0

        scale_range = (maxvalue + top_pad) - minvalue

        scale_division = scale_divisions || (scale_range / 10.0)

        if scale_integers

          scale_division = scale_division < 1 ? 1 : scale_division.round

        end

        rv = []

        maxvalue = maxvalue%scale_division == 0 ? 

          maxvalue : maxvalue + scale_division

        minvalue.step( maxvalue, scale_division ) {|v| rv << v}

        return rv

      end

      def get_y_labels

        @config[:fields]

      end

      def y_label_offset( height )

        height / -2.0

      end

      def draw_data

        minvalue = min_value

        fieldheight = field_height

        unit_size = (@graph_width.to_f - font_size*2*right_font ) /

                        (get_x_labels.max - get_x_labels.min )

        bargap = bar_gap ? (fieldheight < 10 ? fieldheight / 2 : 10) : 0

        bar_height = fieldheight - bargap

        bar_height /= @data.length if stack == :side

        y_mod = (bar_height / 2) + (font_size / 2)

        field_count = 1

        @config[:fields].each_index { |i|

          dataset_count = 0

          for dataset in @data

            value = dataset[:data][i]

            top = @graph_height - (fieldheight * field_count)

            top += (bar_height * dataset_count) if stack == :side

            # cases (assume 0 = +ve):

            #   value  min  length          left

            #    +ve   +ve  value.abs - min minvalue.abs

            #    +ve   -ve  value.abs - 0   minvalue.abs

            #    -ve   -ve  value.abs - 0   minvalue.abs + value

            length = (value.abs - (minvalue > 0 ? minvalue : 0)) * unit_size

            left = (minvalue.abs + (value < 0 ? value : 0)) * unit_size

            @graph.add_element( "rect", {

              "x" => left.to_s,

              "y" => top.to_s,

              "width" => length.to_s,

              "height" => bar_height.to_s,

              "class" => "fill#{dataset_count+1}"

            })

            make_datapoint_text( 

              left+length+5, top+y_mod, value, "text-anchor: start; "

              )

            dataset_count += 1

          end

          field_count += 1

        }

      end

    end

  end

end