Chris@0: require 'rexml/document'
Chris@0: require 'SVG/Graph/Graph'
Chris@0: require 'SVG/Graph/BarBase'
Chris@0: 
Chris@0: module SVG
Chris@0:   module Graph
Chris@0:     # === Create presentation quality SVG bar graphs easily
Chris@0:     #
Chris@0:     # = Synopsis
Chris@0:     #
Chris@0:     #   require 'SVG/Graph/Bar'
Chris@0:     #
Chris@0:     #   fields = %w(Jan Feb Mar);
Chris@0:     #   data_sales_02 = [12, 45, 21]
Chris@0:     #
Chris@0:     #   graph = SVG::Graph::Bar.new(
Chris@0:     #     :height => 500,
Chris@0:     #     :width => 300,
Chris@0:     #     :fields => fields
Chris@0:     #   )
Chris@0:     #
Chris@0:     #   graph.add_data(
Chris@0:     #     :data => data_sales_02,
Chris@0:     #     :title => 'Sales 2002'
Chris@0:     #   )
Chris@0:     #
Chris@0:     #   print "Content-type: image/svg+xml\r\n\r\n"
Chris@0:     #   print graph.burn
Chris@0:     #
Chris@0:     # = Description
Chris@0:     #
Chris@0:     # This object aims to allow you to easily create high quality
Chris@0:     # SVG[http://www.w3c.org/tr/svg bar graphs. You can either use the default
Chris@0:     # style sheet or supply your own. Either way there are many options which
Chris@0:     # can be configured to give you control over how the graph is generated -
Chris@0:     # with or without a key, data elements at each point, title, subtitle etc.
Chris@0:     #
Chris@0:     # = Notes
Chris@0:     #
Chris@0:     # The default stylesheet handles upto 12 data sets, if you
Chris@0:     # use more you must create your own stylesheet and add the
Chris@0:     # additional settings for the extra data sets. You will know
Chris@0:     # if you go over 12 data sets as they will have no style and
Chris@0:     # be in black.
Chris@0:     #
Chris@0:     # = Examples
Chris@0:     #
Chris@0:     # * http://germane-software.com/repositories/public/SVG/test/test.rb
Chris@0:     #
Chris@0:     # = See also
Chris@0:     #
Chris@0:     # * SVG::Graph::Graph
Chris@0:     # * SVG::Graph::BarHorizontal
Chris@0:     # * SVG::Graph::Line
Chris@0:     # * SVG::Graph::Pie
Chris@0:     # * SVG::Graph::Plot
Chris@0:     # * SVG::Graph::TimeSeries
Chris@0:     class Bar < BarBase
Chris@0:       include REXML
Chris@0: 
Chris@0:       # See Graph::initialize and BarBase::set_defaults
Chris@0:       def set_defaults 
Chris@0:         super
Chris@0:         self.top_align = self.top_font = 1
Chris@0:       end
Chris@0: 
Chris@0:       protected
Chris@0: 
Chris@0:       def get_x_labels
Chris@0:         @config[:fields]
Chris@0:       end
Chris@0: 
Chris@0:       def get_y_labels
Chris@0:         maxvalue = max_value
Chris@0:         minvalue = min_value
Chris@0:         range = maxvalue - minvalue
Chris@0: 
Chris@0:         top_pad = range == 0 ? 10 : range / 20.0
Chris@0:         scale_range = (maxvalue + top_pad) - minvalue
Chris@0: 
Chris@0:         scale_division = scale_divisions || (scale_range / 10.0)
Chris@0: 
Chris@0:         if scale_integers
Chris@0:           scale_division = scale_division < 1 ? 1 : scale_division.round
Chris@0:         end
Chris@0: 
Chris@0:         rv = []
Chris@0:         maxvalue = maxvalue%scale_division == 0 ? 
Chris@0:           maxvalue : maxvalue + scale_division
Chris@0:         minvalue.step( maxvalue, scale_division ) {|v| rv << v}
Chris@0:         return rv
Chris@0:       end
Chris@0: 
Chris@0:       def x_label_offset( width )
Chris@0:         width / 2.0
Chris@0:       end
Chris@0: 
Chris@0:       def draw_data
Chris@0:         minvalue = min_value
Chris@0:         fieldwidth = field_width
Chris@0: 
Chris@0:         unit_size =  (@graph_height.to_f - font_size*2*top_font) / 
Chris@0:                           (get_y_labels.max - get_y_labels.min)
Chris@0:         bargap = bar_gap ? (fieldwidth < 10 ? fieldwidth / 2 : 10) : 0
Chris@0: 
Chris@0:         bar_width = fieldwidth - bargap
Chris@0:         bar_width /= @data.length if stack == :side
Chris@0:         x_mod = (@graph_width-bargap)/2 - (stack==:side ? bar_width/2 : 0)
Chris@0:  
Chris@0:         bottom = @graph_height
Chris@0: 
Chris@0:         field_count = 0
Chris@0:         @config[:fields].each_index { |i|
Chris@0:           dataset_count = 0
Chris@0:           for dataset in @data
Chris@0:           
Chris@0:             # cases (assume 0 = +ve):
Chris@0:             #   value  min  length
Chris@0:             #    +ve   +ve  value - min
Chris@0:             #    +ve   -ve  value - 0
Chris@0:             #    -ve   -ve  value.abs - 0
Chris@0:           
Chris@0:             value = dataset[:data][i]
Chris@0:             
Chris@0:             left = (fieldwidth * field_count)
Chris@0:             
Chris@0:             length = (value.abs - (minvalue > 0 ? minvalue : 0)) * unit_size
Chris@0:             # top is 0 if value is negative
Chris@0:             top = bottom - (((value < 0 ? 0 : value) - minvalue) * unit_size)
Chris@0:             left += bar_width * dataset_count if stack == :side
Chris@0:  
Chris@0:             @graph.add_element( "rect", {
Chris@0:               "x" => left.to_s,
Chris@0:               "y" => top.to_s,
Chris@0:               "width" => bar_width.to_s,
Chris@0:               "height" => length.to_s,
Chris@0:               "class" => "fill#{dataset_count+1}"
Chris@0:             })
Chris@0: 
Chris@0:             make_datapoint_text(left + bar_width/2.0, top - 6, value.to_s)
Chris@0:             dataset_count += 1
Chris@0:           end
Chris@0:           field_count += 1
Chris@0:         }
Chris@0:       end
Chris@0:     end
Chris@0:   end
Chris@0: end