Module: Spark

Defined in:
lib/city_watch/util/spark_pr.rb

Class Method Summary collapse

Class Method Details

.discrete(results, options = {}) ⇒ Object 



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# File 'lib/city_watch/util/spark_pr.rb', line 183

def Spark.discrete( results, options = {} )
  options = self.process_options(options)
  o = {
    :height => 14,
    :upper => 0.5,
    :has_min => false,
    :has_max => false
  }.merge(options)
  
  o[:width] ||= results.size*2-1
  
  c = SparkCanvas.new(o[:width], o[:height])
  
  results = Spark.normalize(results, o[:normalize])
  fac = c.height-4
      
  i = -2
  results.each do |r|
    p = c.height - 4 - r*fac
    c.color = r < o[:upper] ? [0x66,0x66,0x66,0xFF] : [0xFF,0x00,0x00,0xFF] 
    c.line(i+=2, p, i, p+3)
  end
      
  c
end

.normalize(arr, type = :linear) ⇒ Object

normalize arr to contain values between 0..1 inclusive



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# File 'lib/city_watch/util/spark_pr.rb', line 119

def Spark.normalize( arr, type = :linear )
  arr.map!{|v| Math.log(v) } if type == :logarithmic
  adj, fac = arr.min, arr.max-arr.min
  arr.map {|v| (v-adj).quo(fac) rescue 0 }
end

.plot(results, options = {}) ⇒ Object

convenience method



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# File 'lib/city_watch/util/spark_pr.rb', line 210

def Spark.plot( results, options = {})
  options = self.process_options(options)
  options[:type] ||= 'smooth'
  self.send(options[:type], results, options).to_png
end

.process_options(options) ⇒ Object 



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# File 'lib/city_watch/util/spark_pr.rb', line 125

def Spark.process_options( options )
  o = options.inject({}) do |o, (key, value)|
    o[key.to_sym] = value ; o
  end
  [:height, :width, :step].each do |k|
    o[k] = o[k].to_i if o.has_key?(k)
  end
  [:has_min, :has_max, :has_last].each do |k|
    o[k] = (o[k] ? true : false) if o.has_key?(k)
  end
  o[:normalize] ||= :linear
  o[:normalize] = o[:normalize].to_sym
  o
end

.smooth(results, options = {}) ⇒ Object 



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# File 'lib/city_watch/util/spark_pr.rb', line 140

def Spark.smooth( results, options = {} )
  options = self.process_options(options)
  o = {
    :step => 2,
    :height => 14,
    :has_min => false,
    :has_max => false
  }.merge(options)
  
  o[:width] ||= (results.size-1)*o[:step] + 5
  
  c = SparkCanvas.new(o[:width], o[:height])
  
  results = Spark.normalize(results, o[:normalize])
  fac = c.height-5
  i = -o[:step]
  coords = results.map do |r| 
    [(i += o[:step])+2, c.height - 3 - r*fac ]
  end
  
  c.color = [0xB0, 0xB0, 0xB0, 0xFF]
  c.polyline coords
  
  if o[:has_min]
    min_pt = coords[results.index(results.min)]
    c.color = [0x80, 0x80, 0x00, 0x70]
    c.rectangle(min_pt[0]-2, min_pt[1]-2, min_pt[0]+2, min_pt[1]+2)
  end
  
  if o[:has_max]
    max_pt = coords[results.index(results.max)]
    c.color = [0x00, 0x80, 0x00, 0x70]
    c.rectangle(max_pt[0]-2, max_pt[1]-2, max_pt[0]+2, max_pt[1]+2)
  end
  
  if o[:has_last]
    c.color = [0xFF, 0x00, 0x00, 0x70]
    c.rectangle(coords.last[0]-2, coords.last[1]-2, coords.last[0]+2, coords.last[1]+2)
  end
  
  c
end