1 files changed, 137 insertions, 0 deletions
diff --git a/lib/SVG/Graph/Bar.rb b/lib/SVG/Graph/Bar.rb
new file mode 100644
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+++ b/lib/SVG/Graph/Bar.rb
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+require 'rexml/document'
+require 'SVG/Graph/Graph'
+require 'SVG/Graph/BarBase'
+
+module SVG
+  module Graph
+    # === Create presentation quality SVG bar graphs easily
+    #
+    # = Synopsis
+    #
+    #   require 'SVG/Graph/Bar'
+    #
+    #   fields = %w(Jan Feb Mar);
+    #   data_sales_02 = [12, 45, 21]
+    #
+    #   graph = SVG::Graph::Bar.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[http://www.w3c.org/tr/svg 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.
+    #
+    # = Notes
+    #
+    # The default stylesheet handles upto 12 data sets, if you
+    # use more you must create your own stylesheet and add the
+    # additional settings for the extra data sets. You will know
+    # if you go over 12 data sets as they will have no style and
+    # be in black.
+    #
+    # = Examples
+    #
+    # * http://germane-software.com/repositories/public/SVG/test/test.rb
+    #
+    # = See also
+    #
+    # * SVG::Graph::Graph
+    # * SVG::Graph::BarHorizontal
+    # * SVG::Graph::Line
+    # * SVG::Graph::Pie
+    # * SVG::Graph::Plot
+    # * SVG::Graph::TimeSeries
+    class Bar < BarBase
+      include REXML
+
+      # See Graph::initialize and BarBase::set_defaults
+      def set_defaults 
+        super
+        self.top_align = self.top_font = 1
+      end
+
+      protected
+
+      def get_x_labels
+        @config[:fields]
+      end
+
+      def get_y_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 x_label_offset( width )
+        width / 2.0
+      end
+
+      def draw_data
+        fieldwidth = field_width
+        maxvalue = max_value
+        minvalue = min_value
+
+        fieldheight =  (@graph_height.to_f - font_size*2*top_font) / 
+                          (get_y_labels.max - get_y_labels.min)
+        bargap = bar_gap ? (fieldwidth < 10 ? fieldwidth / 2 : 10) : 0
+
+        subbar_width = fieldwidth - bargap
+        subbar_width /= @data.length if stack == :side
+        x_mod = (@graph_width-bargap)/2 - (stack==:side ? subbar_width/2 : 0)
+        # Y1
+        p2 = @graph_height
+        # to X2
+        field_count = 0
+        @config[:fields].each_index { |i|
+          dataset_count = 0
+          for dataset in @data
+            # X1
+            p1 = (fieldwidth * field_count)
+            # to Y2
+            p3 = @graph_height - ((dataset[:data][i] - minvalue) * fieldheight)
+            p1 += subbar_width * dataset_count if stack == :side
+            @graph.add_element( "path", {
+              "class" => "fill#{dataset_count+1}",
+              "d" => "M#{p1} #{p2} V#{p3} h#{subbar_width} V#{p2} Z"
+            })
+            make_datapoint_text(
+              p1 + subbar_width/2.0,
+              p3 - 6,
+              dataset[:data][i].to_s)
+            dataset_count += 1
+          end
+          field_count += 1
+        }
+      end
+    end
+  end
+end