littlebrat.rb

require 'rubygems'
require 'gosu'

class LittleBrat < Gosu::Window
  LETTER_LIMIT = 100
  def initialize
    # Full resolution, fullscreen
    super(Gosu.screen_width, Gosu.screen_height, true)
    self.caption = "Leave me alone you little brat!"
    # The letters the little brat hits on the keyboard
    @letters, @new_letters = [], []
    @redraw = true # init this because it needs to be true or false
  end

  def update
    if !@new_letters.empty?
      # Add new letter to the queue
      while str = @new_letters.shift
        @letters.push(Letter.new(self, str))
      end
      # Keep the total number of letter sprites at a managable number
      @letters = @letters[-LETTER_LIMIT..-1] if @letters.size > LETTER_LIMIT
      # We updated the letters, so we need to redraw
      @redraw = true
    end
  end

  def draw
    @letters.each { |letter| letter.draw }
    @redraw = false # Done drawing, don't need to draw no more
  end

  def needs_redraw?
    @redraw # Don't paint/draw unless we need to
  end

  def needs_cursor?
    false # Don't show the cursor, even on Ubuntu
  end

  def button_down(id) # Callback, not on main thread
    close if close? # Close if we press the right keys
    @new_letters.push str_from_button_id(id)
  end

  def str_from_button_id(id)
    # TODO: Handle space and arrow keys
    Gosu::Window.button_id_to_char(id) || random_letter
  end

  def random_letter
    @random_letters ||= %w{ ▲ ▼ ☻ ♠ ♣ ♥ ♦ ☀ ☁ ☂ ✔ ✘ ☎ ✈ ✪ }
    @random_letters[rand @random_letters.size]
  end

  def close?
    (button_down? Gosu::KbEscape or button_down? Gosu::KbLeftControl or
     button_down? Gosu::KbRightControl) &&
    (button_down? Gosu::KbQ or button_down? Gosu::KbW or
     button_down? Gosu::KbZ or button_down? Gosu::KbC or
     button_down? Gosu::KbBackspace or button_down? Gosu::KbDelete)
  end
  
  class Letter
    Z_ORDER = 3

    def initialize(window, text)
      @image = Gosu::Image.from_text(window, text, Gosu::default_font_name,
                                     random_text_size(window))
      @color = random_color # Image text is white, so this is to modulate it
      @x, @y = random_position(window)
    end

    def draw
      @image.draw(@x, @y, Z_ORDER, 0.5, 0.5, @color)
    end

    def random_text_size(window)
      window.height / (rand(3) + 1)
    end

    def random_color
      color       = Gosu::Color.new(0xff000000)
      color.red   = rand(255 - 40) + 40
      color.green = rand(255 - 40) + 40
      color.blue  = rand(255 - 40) + 40
      color
    end

    def random_position(window)
      offset = window.height / 20
      [ rand * (window.width  + offset) - (offset * 2), 
        rand * (window.height + offset) - (offset * 2) ]
    end
  end
end

# Time to shut the brats up!
LittleBrat.new.show