Class: AsciiCharts::Chart

Inherits:
Object
  • Object
show all
Defined in:
lib/ascii_charts.rb

Direct Known Subclasses

Cartesian

Constant Summary collapse

DEFAULT_MAX_Y_VALS = 
20
DEFAULT_MIN_Y_VALS = 
10
STEPS = 
[1, 2, 5]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data, options = {}) ⇒ Chart

data is a sorted array of [x, y] pairs



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# File 'lib/ascii_charts.rb', line 14

def initialize(data, options={})
  @data = data
  @options = options
end

Instance Attribute Details

#data ⇒ Object (readonly)

Returns the value of attribute data.



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# File 'lib/ascii_charts.rb', line 7

def data
  @data
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/ascii_charts.rb', line 7

def options
  @options
end

Instance Method Details

#all_ints ⇒ Object 



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# File 'lib/ascii_charts.rb', line 136

def all_ints
  if !defined? @all_ints
    scan_data
  end
  @all_ints
end

#draw ⇒ Object 



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# File 'lib/ascii_charts.rb', line 215

def draw
  lines.join("\n")
end

#from_step(val) ⇒ Object 



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# File 'lib/ascii_charts.rb', line 62

def from_step(val)
  if 0 == val
    [0, 0]
  else
    order = Math.log10(val).floor.to_i
    num = (val / (10 ** order))
    [num, order]
  end
end

#lines ⇒ Object 



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# File 'lib/ascii_charts.rb', line 211

def lines
  raise "lines must be overridden"
end

#max_xval_width ⇒ Object 



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# File 'lib/ascii_charts.rb', line 167

def max_xval_width
  if !defined? @max_xval_width
    scan_data
  end
  @max_xval_width
end

#max_yval ⇒ Object 



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# File 'lib/ascii_charts.rb', line 122

def max_yval
  if !defined? @max_yval
    scan_data
  end
  @max_yval
end

#max_yval_width ⇒ Object 



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# File 'lib/ascii_charts.rb', line 174

def max_yval_width
  if !defined? @max_yval_width
    scan_y_range
  end
  @max_yval_width
end

#min_yval ⇒ Object 



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# File 'lib/ascii_charts.rb', line 129

def min_yval
  if !defined? @min_yval
    scan_data
  end
  @min_yval
end

#nearest_step(val) ⇒ Object 



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# File 'lib/ascii_charts.rb', line 81

def nearest_step(val)
  num, order = self.from_step(val)
  self.to_step(2, order) ##@@
end

#next_step_down(val) ⇒ Object 



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# File 'lib/ascii_charts.rb', line 96

def next_step_down(val)
  num, order = self.from_step(val)
  next_index = STEPS.index(num.to_i) - 1
  if -1 == next_index
    STEPS.size - 1
    order -= 1
  end
  self.to_step(STEPS[next_index], order)
end

#next_step_up(val) ⇒ Object 



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# File 'lib/ascii_charts.rb', line 86

def next_step_up(val)
  num, order = self.from_step(val)
  next_index = STEPS.index(num.to_i) + 1
  if STEPS.size == next_index
    next_index = 0
    order += 1
  end
  self.to_step(STEPS[next_index], order)
end

#round_value(val) ⇒ Object

round to nearest step size, making sure we curtail precision to same order of magnitude as the step size to avoid 0.4 + 0.2 = 0.6000000000000001



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# File 'lib/ascii_charts.rb', line 107

def round_value(val)
  remainder = val % self.step_size
  unprecised = if (remainder * 2) >= self.step_size
                  (val - remainder) + self.step_size
                else
                  val - remainder
                end
  if self.step_size < 1
    precision = -Math.log10(self.step_size).floor
    (unprecised * (10 ** precision)).to_i.to_f / (10 ** precision)
  else
    unprecised
  end      
end

#rounded_data ⇒ Object 



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# File 'lib/ascii_charts.rb', line 20

def rounded_data
  @rounded_data ||= self.data.map{|pair| [pair[0], self.round_value(pair[1])]}
end

#scan_data ⇒ Object 



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# File 'lib/ascii_charts.rb', line 143

def scan_data
  @max_yval = 0
  @min_yval = 0
  @all_ints = true

  @max_xval_width = 1

  self.data.each do |pair|
    if pair[1] > @max_yval
      @max_yval = pair[1]
    end
    if pair[1] < @min_yval
      @min_yval = pair[1]
    end
    if @all_ints && !pair[1].is_a?(Integer)
      @all_ints = false
    end

    if (xw = pair[0].to_s.length) > @max_xval_width
      @max_xval_width = xw
    end
  end
end

#scan_y_range ⇒ Object 



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# File 'lib/ascii_charts.rb', line 181

def scan_y_range
  @max_yval_width = 1

  self.y_range.each do |yval|
    if (yw = yval.to_s.length) > @max_yval_width
      @max_yval_width = yw
    end
  end
end

#step_size ⇒ Object 



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# File 'lib/ascii_charts.rb', line 24

def step_size
  if !defined? @step_size
    if self.options[:y_step_size]
      @step_size = self.options[:y_step_size]
    else
      max_y_vals = self.options[:max_y_vals] || DEFAULT_MAX_Y_VALS
      min_y_vals = self.options[:max_y_vals] || DEFAULT_MIN_Y_VALS
      y_span = (self.max_yval - self.min_yval).to_f

      step_size = self.nearest_step( y_span.to_f / (self.data.size + 1) )

      if @all_ints && (step_size < 1)
        step_size = 1
      else
        while (y_span / step_size) < min_y_vals
          candidate_step_size = self.next_step_down(step_size)
          if @all_ints && (candidate_step_size < 1) ## don't go below one
            break
          end
          step_size = candidate_step_size
        end
      end

      #go up if we undershot, or were never over
      while (y_span / step_size) > max_y_vals
        step_size = self.next_step_up(step_size)
      end
      @step_size = step_size
    end
    if !@all_ints && @step_size.is_a?(Integer)
      @step_size = @step_size.to_f
    end
  end
  @step_size
end

#to_step(num, order) ⇒ Object 



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# File 'lib/ascii_charts.rb', line 72

def to_step(num, order)
  s = num * (10 ** order)
  if order < 0        
    s.to_f
  else
    s
  end
end

#to_string ⇒ Object 



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# File 'lib/ascii_charts.rb', line 219

def to_string
  draw
end

#y_range ⇒ Object 



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# File 'lib/ascii_charts.rb', line 191

def y_range
  if !defined? @y_range
    @y_range = []
    first_y = self.round_value(self.min_yval)
    if first_y > self.min_yval
      first_y = first_y - self.step_size
    end
    last_y = self.round_value(self.max_yval)
    if last_y < self.max_yval
      last_y = last_y + self.step_size
    end
    current_y = first_y
    while current_y <= last_y
      @y_range << current_y
      current_y = self.round_value(current_y + self.step_size) ## to avoid fp arithmetic oddness
    end
  end
  @y_range
end