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Mazes for Programmers

Displaying Colored Mazes

Learn the code to display colored mazes in Ruby.

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The ColoredGrid class

Now we can subclass Grid and create a ColoredGrid class, which will implement our Dijkstra-based coloring rules. The code is shown below:

C++
require 'grid'
require 'chunky_png'
class ColoredGrid < Grid
  def distances=(distances) 
    @distances = distances
    farthest, @maximum = distances.max 
  end
  def background_color_for(cell) 
    distance = @distances[cell] or return nil
    intensity = (@maximum - distance).to_f / @maximum 
    dark = (255 * intensity).round
    bright = 128 + (127 * intensity).round 
    ChunkyPNG::Color.rgb(dark, bright, dark) 
  end
end

Code explanation

Lines 5–8: Our subclass implements a writer method that we’ll call distances=(distances). The distances= method simply stores the distances mapping and caches the mapping’s largest distance value as @maximum.

Line 10: Our subclass also implements the method: background_color_for(cell).

Lines 12–14: ...