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require 'SVG/Graph/Graph'

module SVG

  module Graph

    # === Create presentation quality SVG pie graphs easily

    # 

    # == Synopsis

    # 

    #   require 'SVG/Graph/Pie'

    # 

    #   fields = %w(Jan Feb Mar)

    #   data_sales_02 = [12, 45, 21]

    #   

    #   graph = SVG::Graph::Pie.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 pie 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, display percent on pie chart,

    # title, subtitle etc.

    #

    # = Examples

    # 

    # http://www.germane-software/repositories/public/SVG/test/single.rb

    # 

    # == See also

    #

    # * SVG::Graph::Graph

    # * SVG::Graph::BarHorizontal

    # * SVG::Graph::Bar

    # * SVG::Graph::Line

    # * 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 Pie < Graph

      # Defaults are those set by Graph::initialize, and

      # [show_shadow] true

      # [shadow_offset] 10

      # [show_data_labels] false

      # [show_actual_values] false

      # [show_percent] true

      # [show_key_data_labels] true

      # [show_key_actual_values] true

      # [show_key_percent] false

      # [expanded] false

      # [expand_greatest] false

      # [expand_gap] 10

      # [show_x_labels] false

      # [show_y_labels] false

      # [datapoint_font_size] 12

      def set_defaults

        init_with(

          :show_shadow                        => true,

          :shadow_offset                => 10, 

          :show_data_labels              => false,

          :show_actual_values     => false,

          :show_percent                        => true,

          :show_key_data_labels          => true,

          :show_key_actual_values => true,

          :show_key_percent                    => false,

          :expanded                                        => false,

          :expand_greatest                    => false,

          :expand_gap             => 10,

          :show_x_labels          => false,

          :show_y_labels          => false,

          :datapoint_font_size    => 12

        )

        @data = []

      end

      # Adds a data set to the graph.

      #

      #   graph.add_data( { :data => [1,2,3,4] } )

      #

      # Note that the :title is not necessary.  If multiple

      # data sets are added to the graph, the pie chart will

      # display the +sums+ of the data.  EG:

      #

      #   graph.add_data( { :data => [1,2,3,4] } )

      #   graph.add_data( { :data => [2,3,5,9] } )

      #

      # is the same as:

      #

      #   graph.add_data( { :data => [3,5,8,13] } )

      def add_data arg

        arg[:data].each_index {|idx|

          @data[idx] = 0 unless @data[idx]

          @data[idx] += arg[:data][idx]

        }

      end

      # If true, displays a drop shadow for the chart

      attr_accessor :show_shadow 

      # Sets the offset of the shadow from the pie chart

      attr_accessor :shadow_offset

      # If true, display the data labels on the chart

      attr_accessor :show_data_labels 

      # If true, display the actual field values in the data labels

      attr_accessor :show_actual_values 

      # If true, display the percentage value of each pie wedge in the data

      # labels

      attr_accessor :show_percent

      # If true, display the labels in the key

      attr_accessor :show_key_data_labels 

      # If true, display the actual value of the field in the key

      attr_accessor :show_key_actual_values 

      # If true, display the percentage value of the wedges in the key

      attr_accessor :show_key_percent

      # If true, "explode" the pie (put space between the wedges)

      attr_accessor :expanded 

      # If true, expand the largest pie wedge

      attr_accessor :expand_greatest 

      # The amount of space between expanded wedges

      attr_accessor :expand_gap 

      # The font size of the data point labels

      attr_accessor :datapoint_font_size

      protected

      def add_defs defs

        gradient = defs.add_element( "filter", {

          "id"=>"dropshadow",

          "width" => "1.2",

          "height" => "1.2",

        } )

        gradient.add_element( "feGaussianBlur", {

          "stdDeviation" => "4",

          "result" => "blur"

        })

      end

      # We don't need the graph

      def draw_graph

      end

      def get_y_labels

        [""]

      end

      def get_x_labels

        [""]

      end

      def keys

        total = 0

        max_value = 0

        @data.each {|x| total += x }

        percent_scale = 100.0 / total

        count = -1

        a = @config[:fields].collect{ |x|

          count += 1

          v = @data[count]

          perc = show_key_percent ? " "+(v * percent_scale).round.to_s+"%" : ""

          x + " [" + v.to_s + "]" + perc

        }

      end

      RADIANS = Math::PI/180

      def draw_data

        @graph = @root.add_element( "g" )

        background = @graph.add_element("g")

        midground = @graph.add_element("g")

        diameter = @graph_height > @graph_width ? @graph_width : @graph_height

        diameter -= expand_gap if expanded or expand_greatest

        diameter -= datapoint_font_size if show_data_labels

        diameter -= 10 if show_shadow

        radius = diameter / 2.0

        xoff = (width - diameter) / 2

        yoff = (height - @border_bottom - diameter)

        yoff -= 10 if show_shadow

        @graph.attributes['transform'] = "translate( #{xoff} #{yoff} )"

        wedge_text_pad = 5

        wedge_text_pad = 20 if show_percent and show_data_labels

        total = 0

        max_value = 0

        @data.each {|x| 

          max_value = max_value < x ? x : max_value

          total += x 

        }

        percent_scale = 100.0 / total

        prev_percent = 0

        rad_mult = 3.6 * RADIANS

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

          value = @data[count]

          percent = percent_scale * value

          radians = prev_percent * rad_mult

          x_start = radius+(Math.sin(radians) * radius)

          y_start = radius-(Math.cos(radians) * radius)

          radians = (prev_percent+percent) * rad_mult

          x_end = radius+(Math.sin(radians) * radius)

          x_end -= 0.00001 if @data.length == 1

          y_end = radius-(Math.cos(radians) * radius)

          path = "M#{radius},#{radius} L#{x_start},#{y_start} "+

            "A#{radius},#{radius} "+

            "0, #{percent >= 50 ? '1' : '0'},1, "+

            "#{x_end} #{y_end} Z"

          wedge = @foreground.add_element( "path", {

            "d" => path,

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

          })

          translate = nil

          tx = 0

          ty = 0

          half_percent = prev_percent + percent / 2

          radians = half_percent * rad_mult

          if show_shadow

            shadow = background.add_element( "path", {

              "d" => path,

              "filter" => "url(#dropshadow)",

              "style" => "fill: #ccc; stroke: none;"

            })

            clear = midground.add_element( "path", {

              "d" => path,

              "style" => "fill: #fff; stroke: none;"

            })

          end

          if expanded or (expand_greatest && value == max_value)

            tx = (Math.sin(radians) * expand_gap)

            ty = -(Math.cos(radians) * expand_gap)

            translate = "translate( #{tx} #{ty} )"

            wedge.attributes["transform"] = translate

            clear.attributes["transform"] = translate if clear

          end

          if show_shadow

            shadow.attributes["transform"] = 

              "translate( #{tx+shadow_offset} #{ty+shadow_offset} )"

          end

          if show_data_labels and value != 0

            label = ""

            label += @config[:fields][count] if show_key_data_labels

            label += " ["+value.to_s+"]" if show_actual_values

            label += " "+percent.round.to_s+"%" if show_percent

            msr = Math.sin(radians)

            mcr = Math.cos(radians)

            tx = radius + (msr * radius)

            ty = radius -(mcr * radius)

            if expanded or (expand_greatest && value == max_value)

              tx += (msr * expand_gap)

              ty -= (mcr * expand_gap)

            end

            @foreground.add_element( "text", {

              "x" => tx.to_s,

              "y" => ty.to_s,

              "class" => "dataPointLabel",

              "style" => "stroke: #fff; stroke-width: 2;"

            }).text = label.to_s

            @foreground.add_element( "text", {

              "x" => tx.to_s,

              "y" => ty.to_s,

              "class" => "dataPointLabel",

            }).text = label.to_s

          end

          prev_percent += percent

        }

      end

      def round val, to

        up = 10**to.to_f

        (val * up).to_i / up

      end

      def get_css

        return <<EOL

.dataPointLabel{

        fill: #000000;

        text-anchor:middle;

        font-size: #{datapoint_font_size}px;

        font-family: "Arial", sans-serif;

        font-weight: normal;

}

/* key - MUST match fill styles */

.key1,.fill1{

        fill: #ff0000;

        fill-opacity: 0.7;

        stroke: none;

        stroke-width: 1px;        

}

.key2,.fill2{

        fill: #0000ff;

        fill-opacity: 0.7;

        stroke: none;

        stroke-width: 1px;        

}

.key3,.fill3{

        fill-opacity: 0.7;

        fill: #00ff00;

        stroke: none;

        stroke-width: 1px;        

}

.key4,.fill4{

        fill-opacity: 0.7;

        fill: #ffcc00;

        stroke: none;

        stroke-width: 1px;        

}

.key5,.fill5{

        fill-opacity: 0.7;

        fill: #00ccff;

        stroke: none;

        stroke-width: 1px;        

}

.key6,.fill6{

        fill-opacity: 0.7;

        fill: #ff00ff;

        stroke: none;

        stroke-width: 1px;        

}

.key7,.fill7{

        fill-opacity: 0.7;

        fill: #00ff99;

        stroke: none;

        stroke-width: 1px;        

}

.key8,.fill8{

        fill-opacity: 0.7;

        fill: #ffff00;

        stroke: none;

        stroke-width: 1px;        

}

.key9,.fill9{

        fill-opacity: 0.7;

        fill: #cc6666;

        stroke: none;

        stroke-width: 1px;        

}

.key10,.fill10{

        fill-opacity: 0.7;

        fill: #663399;

        stroke: none;

        stroke-width: 1px;        

}

.key11,.fill11{

        fill-opacity: 0.7;

        fill: #339900;

        stroke: none;

        stroke-width: 1px;        

}

.key12,.fill12{

        fill-opacity: 0.7;

        fill: #9966FF;

        stroke: none;

        stroke-width: 1px;        

}

EOL

      end

    end

  end

end