Drawing "inome", a traditional Japanese design in the shape of a heart

inome-drawer.rb

#!/usr/bin/env ruby

# inome-drawer.rb : drawing "inome", a traditional Japanese design in the shape of a heart
#   by takehikom

# See also:
#   http://shoujuin.boo.jp/?page_id=466
#   http://d.hatena.ne.jp/takehikom/20180619/1529420399

class InomeDrawer
  def initialize(h = {})
    @unit = (h[:unit] || 52).to_f
    @margin = (h[:margin] || 5).to_f
    @image_filename = h[:filename] || "inome.png"
    @background = h[:background] || "cyan"
    # @background = h[:background] || "none"
    @stroke = h[:foreground] || "red"
    @strokewidth = (h[:strokewidth] || 2).to_f
    @draw_type = h[:drawtype]
    @omit_grid = h[:omitgrid]

    init_length
  end
  attr_reader :unit, :margin

  def start
    case @draw_type
    when :lineandcircle
      create_inome_by_line_and_circle
    when :path
      create_inome_by_path
    else
      # create_inome_by_line_and_circle
      create_inome_by_path
    end
  end

  def init_length
    @width = @unit * 7 + @margin * 2
    @height = @unit * 6 + @margin * 2
    @radius = @unit * 5 / 3
    @radius2 = @radius * Math.sqrt(2.0) * 0.5
  end

  def unit=(u)
    @unit = u
    init_length
  end

  def margin=(m)
    @margin = m
    init_length
  end

  def create_inome_by_path
    init_command
    add_grid if !@omit_grid

    @command += " -stroke #{@stroke} -strokewidth #{@strokewidth} -fill none"
    @command += " -draw \"translate #{@margin},#{@margin} path \'#{inome_path}\'\""

    close_command
    puts @command
    system @command
  end

  def create_inome_by_line_and_circle
    init_command
    add_grid if !@omit_grid

    # 左右の円
    @command += " -stroke #{@stroke} -strokewidth #{@strokewidth} -fill none"
    x1 = @margin + @unit * 0.5 + @radius2
    y1 = @margin + @unit * 3 - @radius2
    x2, y2 = x1, y1 - @radius
    @command += " -draw \"circle #{[x1, y1, x2, y2].join(',')}\""
    x1 = @width - @margin - @unit * 0.5 - @radius2
    x2 = x1
    @command += " -draw \"circle #{[x1, y1, x2, y2].join(',')}\""

    # 直線（下部）
    x1, y1 = @margin + @unit * 3.5, @height - @margin
    x2, y2 = x1 - @unit * 3.0, y1 - @unit * 3.0
    @command += " -draw \"line #{[x1, y1, x2, y2].join(',')}\""
    x2, y2 = x1 + @unit * 3.0, y1 - @unit * 3.0
    @command += " -draw \"line #{[x1, y1, x2, y2].join(',')}\""

    # 直線（上部）
    x3 = @margin + @unit * 0.5 + @radius2 * 2
    y3 = @margin + @unit * 3 - @radius2 * 2
    x4 = @margin + @unit * 3.5
    y4 = y3 + (x4 - x3)
    @command += " -draw \"line #{[x3, y3, x4, y4].join(',')}\""
    x3 = @width - (@margin + @unit * 0.5 + @radius2 * 2)
    @command += " -draw \"line #{[x3, y3, x4, y4].join(',')}\""

    close_command
    puts @command
    system @command
  end

  def init_command
    @command = "convert -size #{@width}x#{@height} xc:#{@background}"
  end

  def add_grid
    # 格子（座標確認用）
    @command += " -stroke blue -strokewidth 1 -fill none"
    0.upto(6) do |i|
      x1, y1 = @margin, @margin + @unit * i
      x2, y2 = @width - @margin, y1
      @command += " -draw \"line #{[x1, y1, x2, y2].join(',')}\""
    end
    0.upto(7) do |i|
      x1, y1 = @margin + @unit * i, @margin
      x2, y2 = x1, @height - @margin
      @command += " -draw \"line #{[x1, y1, x2, y2].join(',')}\""
    end
  end

  def close_command
    @command += " -quality 92 #{@image_filename}"
  end

  def inome_path
    # 猪目の形状
    x1 = @unit * 3.5
    y1 = @unit * 6
    @path = "M #{x1},#{y1}"
    x2 = x1 + @unit * 3
    y2 = y1 - @unit * 3
    @path += " L #{x2},#{y2}"
    r3 = @radius2
    x3 = x2 - r3 * 2
    y3 = y2 - r3 * 2
    @path += " A #{r3},#{r3},0,0,0,#{x3},#{y3}"
    x4 = x1
    y4 = y3 + (x3 - x4)
    @path += " L #{x4},#{y4}"
    x5 = x4 - (x3 - x4)
    y5 = y3
    @path += " L #{x5},#{y5}"
    x6 = x1 - @unit * 3
    y6 = y2
    @path += " A #{r3},#{r3},0,0,0,#{x6},#{y6}"
    @path += " Z"

    @path
  end
end

if __FILE__ == $0
  InomeDrawer.new.start
end