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

For creating SVG plots of scalar data

Synopsis

  require 'SVG/Graph/Plot'

  # Data sets are x,y pairs
  # Note that multiple data sets can differ in length, and that the
  # data in the datasets needn't be in order; they will be ordered
  # by the plot along the X-axis.
  projection = [
    6, 11,    0, 5,   18, 7,   1, 11,   13, 9,   1, 2,   19, 0,   3, 13,
    7, 9
  ]
  actual = [
    0, 18,    8, 15,    9, 4,   18, 14,   10, 2,   11, 6,  14, 12,
    15, 6,   4, 17,   2, 12
  ]

  graph = SVG::Graph::Plot.new({
          :height => 500,
          :width => 300,
    :key => true,
    :scale_x_integers => true,
    :scale_y_integerrs => true,
  })

  graph.add_data({
          :data => projection
    :title => 'Projected',
  })

  graph.add_data({
          :data => actual,
    :title => 'Actual',
  })

  print graph.burn()

Description

Produces a graph of scalar data.

This object aims to allow you to easily create high quality SVG scalar plots. 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

www.germane-software/repositories/public/SVG/test/plot.rb

Notes

The default stylesheet handles upto 10 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 10 data sets as they will have no style and be in black.

Unlike the other types of charts, data sets must contain x,y pairs:

  [ 1, 2 ]    # A data set with 1 point: (1,2)
  [ 1,2, 5,6] # A data set with 2 points: (1,2) and (5,6)

See also

Author

Sean E. Russell <serATgermaneHYPHENsoftwareDOTcom>

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

Methods

Constants

X = 0
Y = 1

Attributes

area_fill  [RW]  Fill the area under the line
min_x_value  [RW]  Set the minimum value of the X axis
min_y_value  [RW]  Set the minimum value of the Y axis
scale_x_divisions  [RW]  Determines the scaling for the X axis divisions.
  graph.scale_x_divisions = 2

would cause the graph to attempt to generate labels stepped by 2; EG: 0,2,4,6,8…

scale_x_integers  [RW]  Make the X axis labels integers
scale_y_divisions  [RW]  Determines the scaling for the Y axis divisions.
  graph.scale_y_divisions = 0.5

would cause the graph to attempt to generate labels stepped by 0.5; EG: 0, 0.5, 1, 1.5, 2, …

scale_y_integers  [RW]  Make the Y axis labels integers
show_data_points  [RW]  Show a small circle on the graph where the line goes from one point to the next.

Public Instance methods

Adds data to the plot. The data must be in X,Y pairs; EG

  [ 1, 2 ]    # A data set with 1 point: (1,2)
  [ 1,2, 5,6] # A data set with 2 points: (1,2) and (5,6)

[Source]

# File lib/SVG/Graph/Plot.rb, line 137
      def add_data data
              
        @data = [] unless @data

        raise "No data provided by #{conf.inspect}" unless data[:data] and
        data[:data].kind_of? Array
        raise "Data supplied must be x,y pairs!  "+
          "The data provided contained an odd set of "+
          "data points" unless data[:data].length % 2 == 0
        return if data[:data].length == 0

        x = []
        y = []
        data[:data].each_index {|i|
          (i%2 == 0 ? x : y) << data[:data][i]
        }
        sort( x, y )
        data[:data] = [x,y]
        @data << data
      end

In addition to the defaults set by Graph::initialize, sets

show_data_values
true
show_data_points
true
area_fill
false
stacked
false

[Source]

# File lib/SVG/Graph/Plot.rb, line 95
      def set_defaults
        init_with(
                  :show_data_values  => true,
                  :show_data_points  => true,
                  :area_fill         => false,
                  :stacked           => false
                 )
                 self.top_align = self.right_align = self.top_font = self.right_font = 1
      end

Protected Instance methods

[Source]

# File lib/SVG/Graph/Plot.rb, line 165
      def calculate_left_margin
        super
        label_left = get_x_labels[0].to_s.length / 2 * font_size * 0.6
        @border_left = label_left if label_left > @border_left
      end

[Source]

# File lib/SVG/Graph/Plot.rb, line 171
      def calculate_right_margin
        super
        label_right = get_x_labels[-1].to_s.length / 2 * font_size * 0.6
        @border_right = label_right if label_right > @border_right
      end

[Source]

# File lib/SVG/Graph/Plot.rb, line 253
      def draw_data
        line = 1

        x_min, x_max, x_div = x_range
        y_min, y_max, y_div = y_range
        x_step = (@graph_width.to_f - font_size*2) / (x_max-x_min)
        y_step = (@graph_height.to_f -  font_size*2) / (y_max-y_min)

        for data in @data
          x_points = data[:data][X]
          y_points = data[:data][Y]

          lpath = "L"
          x_start = 0
          y_start = 0
          x_points.each_index { |idx|
            x = (x_points[idx] -  x_min) * x_step
            y = @graph_height - (y_points[idx] -  y_min) * y_step
            x_start, y_start = x,y if idx == 0
            lpath << "#{x} #{y} "
          }

          if area_fill
            @graph.add_element( "path", {
              "d" => "M#{x_start} #@graph_height #{lpath} V#@graph_height Z",
              "class" => "fill#{line}"
            })
          end

          @graph.add_element( "path", {
            "d" => "M#{x_start} #{y_start} #{lpath}",
            "class" => "line#{line}"
          })

          if show_data_points || show_data_values
            x_points.each_index { |idx|
              x = (x_points[idx] -  x_min) * x_step
              y = @graph_height - (y_points[idx] -  y_min) * y_step
              if show_data_points
                @graph.add_element( "circle", {
                  "cx" => x.to_s,
                  "cy" => y.to_s,
                  "r" => "2.5",
                  "class" => "dataPoint#{line}"
                })
                add_popup(x, y, format( x_points[idx], y_points[idx] )) if add_popups
              end
              make_datapoint_text( x, y-6, y_points[idx] ) if show_data_values
            }
          end
          line += 1
        end
      end

[Source]

# File lib/SVG/Graph/Plot.rb, line 241
      def field_height
        values = get_y_values
        max = @data.collect{|x| x[:data][Y].max }.max
        if values.length == 1
          dx = values[-1]
        else
          dx = (max - values[-1]).to_f / (values[-1] - values[-2])
        end
        (@graph_height.to_f - font_size*2*top_font) /
          (values.length + dx - top_align)
      end

[Source]

# File lib/SVG/Graph/Plot.rb, line 206
      def field_width
        values = get_x_values
        max = @data.collect{|x| x[:data][X][-1]}.max
        dx = (max - values[-1]).to_f / (values[-1] - values[-2])
        (@graph_width.to_f - font_size*2*right_font) /
          (values.length + dx - right_align)
      end

[Source]

# File lib/SVG/Graph/Plot.rb, line 307
      def format x, y
        "(#{(x * 100).to_i / 100}, #{(y * 100).to_i / 100})"
      end

[Source]

# File lib/SVG/Graph/Plot.rb, line 311
      def get_css
        return "/* default line styles */\n.line1{\n        fill: none;\n        stroke: #ff0000;\n        stroke-width: 1px;     \n}\n.line2{\n        fill: none;\n        stroke: #0000ff;\n        stroke-width: 1px;     \n}\n.line3{\n        fill: none;\n        stroke: #00ff00;\n        stroke-width: 1px;     \n}\n.line4{\n        fill: none;\n        stroke: #ffcc00;\n        stroke-width: 1px;     \n}\n.line5{\n        fill: none;\n        stroke: #00ccff;\n        stroke-width: 1px;     \n}\n.line6{\n        fill: none;\n        stroke: #ff00ff;\n        stroke-width: 1px;     \n}\n.line7{\n        fill: none;\n        stroke: #00ffff;\n        stroke-width: 1px;     \n}\n.line8{\n        fill: none;\n        stroke: #ffff00;\n        stroke-width: 1px;     \n}\n.line9{\n        fill: none;\n        stroke: #ccc6666;\n        stroke-width: 1px;     \n}\n.line10{\n        fill: none;\n        stroke: #663399;\n        stroke-width: 1px;     \n}\n.line11{\n        fill: none;\n        stroke: #339900;\n        stroke-width: 1px;     \n}\n.line12{\n        fill: none;\n        stroke: #9966FF;\n        stroke-width: 1px;     \n}\n/* default fill styles */\n.fill1{\n        fill: #cc0000;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill2{\n        fill: #0000cc;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill3{\n        fill: #00cc00;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill4{\n        fill: #ffcc00;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill5{\n        fill: #00ccff;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill6{\n        fill: #ff00ff;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill7{\n        fill: #00ffff;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill8{\n        fill: #ffff00;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill9{\n        fill: #cc6666;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill10{\n        fill: #663399;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill11{\n        fill: #339900;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill12{\n        fill: #9966FF;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n/* default line styles */\n.key1,.dataPoint1{\n        fill: #ff0000;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key2,.dataPoint2{\n        fill: #0000ff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key3,.dataPoint3{\n        fill: #00ff00;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key4,.dataPoint4{\n        fill: #ffcc00;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key5,.dataPoint5{\n        fill: #00ccff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key6,.dataPoint6{\n        fill: #ff00ff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key7,.dataPoint7{\n        fill: #00ffff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key8,.dataPoint8{\n        fill: #ffff00;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key9,.dataPoint9{\n        fill: #cc6666;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key10,.dataPoint10{\n        fill: #663399;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key11,.dataPoint11{\n        fill: #339900;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key12,.dataPoint12{\n        fill: #9966FF;\n        stroke: none;\n        stroke-width: 1px;     \n}\n"
      end
get_x_labels()

Alias for get_x_values

[Source]

# File lib/SVG/Graph/Plot.rb, line 198
      def get_x_values
        min_value, max_value, scale_division = x_range
        rv = []
        min_value.step( max_value, scale_division ) {|v| rv << v}
        return rv
      end
get_y_labels()

Alias for get_y_values

[Source]

# File lib/SVG/Graph/Plot.rb, line 233
      def get_y_values
        min_value, max_value, scale_division = y_range
        rv = []
        min_value.step( max_value, scale_division ) {|v| rv << v}
        return rv
      end

[Source]

# File lib/SVG/Graph/Plot.rb, line 161
      def keys
        @data.collect{ |x| x[:title] }
      end

[Source]

# File lib/SVG/Graph/Plot.rb, line 180
      def x_range
        max_value = @data.collect{|x| x[:data][X][-1] }.max
        min_value = @data.collect{|x| x[:data][X][0] }.min
        min_value = min_value<min_x_value ? min_value : min_x_value if min_x_value

        range = max_value - min_value
        right_pad = range == 0 ? 10 : range / 20.0
        scale_range = (max_value + right_pad) - min_value

        scale_division = scale_x_divisions || (scale_range / 10.0)

        if scale_x_integers
          scale_division = scale_division < 1 ? 1 : scale_division.round
        end

        [min_value, max_value, scale_division]
      end

[Source]

# File lib/SVG/Graph/Plot.rb, line 215
      def y_range
        max_value = @data.collect{|x| x[:data][Y].max }.max
        min_value = @data.collect{|x| x[:data][Y].min }.min
        min_value = min_value<min_y_value ? min_value : min_y_value if min_y_value

        range = max_value - min_value
        top_pad = range == 0 ? 10 : range / 20.0
        scale_range = (max_value + top_pad) - min_value

        scale_division = scale_y_divisions || (scale_range / 10.0)

        if scale_y_integers
          scale_division = scale_division < 1 ? 1 : scale_division.round
        end

        return [min_value, max_value, scale_division]
      end

[Validate]