[QUIZ] Circle Drawing (#166)

ruby-talk
1

Quick solution. Draws filled circles, corrected for non-square pixels. Can take non-integer x,y and radius.

Here http://pastie.org/214895
or below (not sure how long pastie keeps the content)

Cheers,
Dave

# http://pastie.org/214895

···

#
# Ruby Quiz 166 Circles
# David Phillips
#
# sample output
#
# 0000000000000--|||||||||||||||++++++ !!!!!!!!!!!!!!!!!!!!!!!!!
# 00000000000-----|||||||||||||++++++++ !!!!!!!!!!!!!!!!!!!!!!!
# 0000000000------|||||||||||||+++++++++ \ !!!!!!!!!!!!!!!!!!!!!!!
# 000000000--------|||||||||||++++++\\\\\\\\\\\\\!!!!!!!!!!!!!!!!!!!!!!!
# 000000000----------|||||||++++++\\\\\\\\\\\\\\\\\!!!!!!!!!!!!!!!!!!!!
# 00000000-------------------++++\\\\\\\\\\\\\\\\\\\!!!!!!!!!!!!!!!!!
# 000000000-----------------++++\\\\\\\\\\\\\\\\\\\\\!!!!!!!!!!!!!!!
# 000000-----------------+++\\\\\\\\\\\\\\\\\\\\\\\ !!!!!!!!!
# 0 -----------------+++\\\\\\\\\\\\\\\\\\\\\\\===== !
# ------------- \\\\\\\\\\\\\\\\\\\\\\\\\=======
# XXXX--------- \\\\\\\\\\\\\\\\\\\\\\\=========
# XXXXXXXXXX- \\\\\\\\\\\\\\\\\\\\\\\===========
# XXXXXXXXXXXXX ////\\\\\\\\\\\\\\\\\\\\\\\===========*
# XXXXXXXXXXXXX ////////\\\\\\\\\\\\\\\\\\\\\=============*
# XXXXXXXXXXXXXXX //////////\\\\\\\\\\\\\\\\\\\==============**
# XXXXXXXXXXXXX /////////////\\\\\\\\\\\\\\\=================*
# XXXXXXXXXXXXX //////////////\\\\\\\\\\\\\=================**
# XXXXXXXXX /////////////////// \=======================***
# XXXXXXX ///////////////////// =======================**
# /////////////////// *=====================***
# /////////////////// ***=================*****
# ///////////////// ***===============*****
# /////////////// *****=========*******
# ///////////// ********=**********
# / *************
# *

class Canvas
  def initialize aspect_ratio=1.6
    @rows= []
    @y_multiplier= 1/aspect_ratio
    yield self if block_given?
  end
  
  def set_pixel x, y, char
    x, y = x.round, (@y_multiplier*y).round
    (@rows[y]||=[])[x]=char unless (x<0 || y<0)
  end
  
  def to_s
    @rows.map do |row|
      row.nil? ? '' : row.map{|c|c||=' '}.join
    end.join("\n")
  end
  
  # decided to try a method that doesn't require trig functions
  def draw_circle x, y, r, fill_char='#'
    (x-r).round.upto((x+r).round) do |col|
      (y-r).round.upto(y+r) do |row|
        if (col-x)**2+(row-y)**2 <= r**2
          set_pixel col, row, fill_char
        end
      end # row
    end # col
  end # def
end

canvas= Canvas.new do |c|
  %w[! . + * X 0 = / \\ - |].each do |char|
    c.draw_circle rand(70), rand(30), 4+rand(10), char
  end
end
puts canvas

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