Class: SVG::Graph::Plot

Inherits:
SVG::Graph show all
Defined in:
lib/SVG/Graph/Plot.rb

Overview

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)

Additional possible notation

[ [1,2], 5,6] # A data set with 2 points: (1,2) and (5,6), mixed notation
[ [1,2], [5,6]] # A data set with 2 points: (1,2) and (5,6), nested array

See also

  • SVG::Graph::Graph

  • SVG::Graph::BarHorizontal

  • SVG::Graph::Bar

  • SVG::Graph::Line

  • SVG::Graph::Pie

  • SVG::Graph::TimeSeries

Author

Sean E. Russell <serATgermaneHYPHENsoftwareDOTcom>

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

Direct Known Subclasses

TimeSeries

Constant Summary

Constants included from SVG::Graph

VERSION

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#area_fill ⇒ Object

Fill the area under the line, default: false



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# File 'lib/SVG/Graph/Plot.rb', line 133

def area_fill
  @area_fill
end

#max_x_value ⇒ Object

Set the maximum value of the X axis, if nil the maximum from data is chosen, default: nil



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# File 'lib/SVG/Graph/Plot.rb', line 140

def max_x_value
  @max_x_value
end

#max_y_value ⇒ Object

Set the maximum value of the Y axis, if nil the maximum from data is chosen, default: nil



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# File 'lib/SVG/Graph/Plot.rb', line 144

def max_y_value
  @max_y_value
end

#min_x_value ⇒ Object

Set the minimum value of the X axis, if nil the minimum from data is chosen, default: nil



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# File 'lib/SVG/Graph/Plot.rb', line 138

def min_x_value
  @min_x_value
end

#min_y_value ⇒ Object

Set the minimum value of the Y axis, if nil the minimum from data is chosen, default: nil



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# File 'lib/SVG/Graph/Plot.rb', line 142

def min_y_value
  @min_y_value
end

#round_popups ⇒ Object

Round value of data points in popups to integer, default: true



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# File 'lib/SVG/Graph/Plot.rb', line 148

def round_popups
  @round_popups
end

#scale_x_divisions ⇒ Object

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… default is automatic such that there are 10 labels



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# File 'lib/SVG/Graph/Plot.rb', line 119

def scale_x_divisions
  @scale_x_divisions
end

#scale_x_integers ⇒ Object

Make the X axis labels integers, default: false



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# File 'lib/SVG/Graph/Plot.rb', line 129

def scale_x_integers
  @scale_x_integers
end

#scale_y_divisions ⇒ Object

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, … default is automatic such that there are 10 labels



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# File 'lib/SVG/Graph/Plot.rb', line 127

def scale_y_divisions
  @scale_y_divisions
end

#scale_y_integers ⇒ Object

Make the Y axis labels integers, default: false



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# File 'lib/SVG/Graph/Plot.rb', line 131

def scale_y_integers
  @scale_y_integers
end

#show_data_points ⇒ Object

Show a small circle on the graph where the line goes from one point to the next. default: true



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# File 'lib/SVG/Graph/Plot.rb', line 136

def show_data_points
  @show_data_points
end

#show_lines ⇒ Object

Show lines connecting data points, default: true



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# File 'lib/SVG/Graph/Plot.rb', line 146

def show_lines
  @show_lines
end

Instance Method Details

#add_data(conf) ⇒ Object

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

data_set1 = [ 1, 2 ]    # A data set with 1 point: (1,2)
data_set2 = [ 1,2, 5,6] # A data set with 2 points: (1,2) and (5,6)

It’s also supported to supply nested array or a mix (flatten is applied to the array); EG

data_set2 = [[1,2], 5,6]

or

data_set2 = [[1,2], [5,6]]

graph.add_data({
  :data => data_set1,
  :title => 'single point'
})   
graph.add_data({
  :data => data_set2,
  :title => 'two points'
})



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# File 'lib/SVG/Graph/Plot.rb', line 167

def add_data(conf)
 @data ||= []
  raise "No data provided by #{conf.inspect}" unless conf[:data] and
    conf[:data].kind_of? Array
  # support array of arrays and flatten it
  conf[:data] = conf[:data].flatten
  # check that we have pairs of values
  raise "Data supplied must be x,y pairs!  "+
    "The data provided contained an odd set of "+
    "data points" unless conf[:data].length % 2 == 0
    
  # remove nil values
  conf[:data] = conf[:data].compact
    
  return if conf[:data].length == 0

  conf[:description] ||= Array.new(conf[:data].size/2)
  if conf[:description].size != conf[:data].size/2
    raise "Description for popups does not have same size as provided data: #{conf[:description].size} vs #{conf[:data].size/2}"
  end

  x = []
  y = []
  conf[:data].each_index {|i|
    (i%2 == 0 ? x : y) << conf[:data][i]
  }
  sort( x, y, conf[:description] )
  conf[:data] = [x,y]
  # at the end data looks like:
  # [
  #   [all x values],
  #   [all y values]
  # ]
  @data << conf
end

#set_defaults ⇒ Object

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

show_data_points

true

area_fill

false

stacked

false, will not have any effect if true

show_lines

true

round_popups

true



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# File 'lib/SVG/Graph/Plot.rb', line 100

def set_defaults
  init_with(
    :show_data_points  => true,
    :area_fill         => false,
    :stacked           => false,
    :show_lines        => true,
    :round_popups      => true,
    :scale_x_integers  => false,
    :scale_y_integerrs => false,
   )
end