Class: RailsDataExplorer::Utils::ColorScale

Inherits:
Object
  • Object
show all
Defined in:
lib/rails_data_explorer/utils/color_scale.rb

Overview

Responsibilities:

* Map an input value between -1 and 1 to a color on a color scale.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ColorScale

Returns a new instance of ColorScale.



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# File 'lib/rails_data_explorer/utils/color_scale.rb', line 11

def initialize
  @points = {
    -1 => Color::RGB::Red,
    -0.1 =>  Color::RGB::Black,
    0.1 =>  Color::RGB::Black,
    1 => Color::RGB::Green,
  }
  @gradient = Interpolate::Points.new(@points)
  @gradient.blend_with {|color, other, balance|
    other.mix_with(color, balance * 100.0)
  }
end

Instance Method Details

#compute(input) ⇒ Object 



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# File 'lib/rails_data_explorer/utils/color_scale.rb', line 24

def compute(input)
  @gradient.at(input).html
end

#demo ⇒ Object 



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# File 'lib/rails_data_explorer/utils/color_scale.rb', line 28

def demo
  "<ul>".html_safe +
  (-1).step(1, 0.1).map { |e|
    color = compute(e)
    %(<li style="color: #{ color }">#{ e } (#{ color })</li>)
  }.join.html_safe +
  "</ul>".html_safe
end