A Jan Vantomme processing sketch translated to ruby-processing

# sketch by Jan Vantomme
# Part of a series of articles on Processing 2.
# Blog post here:
# http://vormplus.be/blog/article/drawing-shapes-with-quadratic-vertices
# translated for ruby-processing by Martin Prout 
# Note how to specify fill and background using hexadecimal string for color, 
# this is different from vanilla processing
#

load_library :control_panel

attr_reader :debug, :save_one, :step_angle, :cr, :detail, :panel

def setup
  size 450, 320
  control_panel do |c|
    c.title = "controller"
    c.menu(:detail, ['4', '5', '6', '7', '8', '9', '10' ], '7')
    c.button :toggle_debug
    c.button :save_image
    @panel = c
  end
  @debug = false
  @save_one = false
  smooth 8
end

def draw
  panel.set_visible true
  background color('#BDF018')
  translate width / 2, height / 2
  @step_angle = TWO_PI / (detail.to_i - 1)
  fill color('#ffffff')
  no_stroke
  @cr = map(mouse_x, 0, width, 20, 200)
  begin_shape
  detail.to_i.times { |i|
    if (i == 0)
      vertex cos_x(i), sin_y(i)
    else
      quadratic_vertex cos_cx(i), sin_cy(i), cos_x(i), sin_y(i)
    end
  }
  end_shape(CLOSE)

  if (debug)
    # draw lines between points
    stroke_weight(1)
    no_fill
    stroke(0)

    begin_shape
    detail.to_i.times { |i|
      vertex cos_cx(i), sin_cy(i) unless i == 0
      vertex cos_x(i), sin_y(i)
    }
    end_shape CLOSE

    # draw points
    stroke_weight 8
    detail.to_i.times { |i|
      stroke 0
      point cos_x(i), sin_y(i)
      stroke 255, 0, 0
      point cos_cx(i), sin_cy(i)
    }
  end

  if (save_one)
    save_frame("images/quadraticvertex-#####.png")
    @save_one = false
  end
end

def cos_x(n)
  cos(step_angle * n) * 100
end

def sin_y(n)
  sin(step_angle * n) * 100
end

def cos_cx(n)
  cos(step_angle * n - (step_angle / 2 )) * cr
end

def sin_cy(n)
  sin(step_angle * n - (step_angle / 2 )) * cr
end

def toggle_debug
  @debug = !debug
end

def save_image
  @save_one = true
end