Class SVG::Graph::BarHorizontal
In: lib/SVG/Graph/BarHorizontal.rb
Parent: BarBase

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
63:       def set_defaults
64:         super
65:         init_with( 
66:           :rotate_y_labels    => true,
67:           :show_x_guidelines  => true,
68:           :show_y_guidelines  => false
69:         )
70:         self.right_align = self.right_font = 1
71:       end

Protected Instance methods

[Source]

     # File lib/SVG/Graph/BarHorizontal.rb, line 103
103:       def draw_data
104:         minvalue = min_value
105:         fieldheight = field_height
106: 
107:         unit_size = (@graph_width.to_f - font_size*2*right_font ) /
108:                         (get_x_labels.max - get_x_labels.min )
109:         bargap = bar_gap ? (fieldheight < 10 ? fieldheight / 2 : 10) : 0
110: 
111:         bar_height = fieldheight - bargap
112:         bar_height /= @data.length if stack == :side
113:         y_mod = (bar_height / 2) + (font_size / 2)
114:         
115:         field_count = 1
116:         @config[:fields].each_index { |i|
117:           dataset_count = 0
118:           for dataset in @data
119:             value = dataset[:data][i]
120:             
121:             top = @graph_height - (fieldheight * field_count)
122:             top += (bar_height * dataset_count) if stack == :side
123:             # cases (assume 0 = +ve):
124:             #   value  min  length          left
125:             #    +ve   +ve  value.abs - min minvalue.abs
126:             #    +ve   -ve  value.abs - 0   minvalue.abs
127:             #    -ve   -ve  value.abs - 0   minvalue.abs + value
128:             length = (value.abs - (minvalue > 0 ? minvalue : 0)) * unit_size
129:             left = (minvalue.abs + (value < 0 ? value : 0)) * unit_size
130: 
131:             @graph.add_element( "rect", {
132:               "x" => left.to_s,
133:               "y" => top.to_s,
134:               "width" => length.to_s,
135:               "height" => bar_height.to_s,
136:               "class" => "fill#{dataset_count+1}"
137:             })
138: 
139:             make_datapoint_text( 
140:               left+length+5, top+y_mod, value, "text-anchor: start; "
141:               )
142:             dataset_count += 1
143:           end
144:           field_count += 1
145:         }
146:       end

[Source]

    # File lib/SVG/Graph/BarHorizontal.rb, line 75
75:       def get_x_labels
76:         maxvalue = max_value
77:         minvalue = min_value
78:         range = maxvalue - minvalue
79:         top_pad = range == 0 ? 10 : range / 20.0
80:         scale_range = (maxvalue + top_pad) - minvalue
81: 
82:         scale_division = scale_divisions || (scale_range / 10.0)
83: 
84:         if scale_integers
85:           scale_division = scale_division < 1 ? 1 : scale_division.round
86:         end
87: 
88:         rv = []
89:         maxvalue = maxvalue%scale_division == 0 ? 
90:           maxvalue : maxvalue + scale_division
91:         minvalue.step( maxvalue, scale_division ) {|v| rv << v}
92:         return rv
93:       end

[Source]

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

[Source]

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

[Validate]