Class SVG::Graph::BarHorizontal
In: lib/SVG/Graph/BarHorizontal.rb
Parent: BarBase
Graph Pie Plot BarBase Schedule Line TimeSeries Bar BarHorizontal REXML Graph SVG dot/f_0.png

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

See also

Author

Sean E. Russell <serATgermaneHYPHENsoftwareDOTcom>

Copyright 2004 Sean E. Russell This software is available under the Ruby license

Methods

Public Instance methods

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

rotate_y_labels
true
show_x_guidelines
true
show_y_guidelines
false

[Source]

# File lib/SVG/Graph/BarHorizontal.rb, line 63
      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 Instance methods

[Source]

# File lib/SVG/Graph/BarHorizontal.rb, line 103
      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

[Source]

# File lib/SVG/Graph/BarHorizontal.rb, line 75
      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

[Source]

# File lib/SVG/Graph/BarHorizontal.rb, line 95
      def get_y_labels
        @config[:fields]
      end

[Source]

# File lib/SVG/Graph/BarHorizontal.rb, line 99
      def y_label_offset( height )
        height / -2.0
      end

[Validate]