Rubygame Menu class

menu.rb

require 'rubygame'

class Menu
  def initialize screen, font_file, background, menu=[]

    @background = background
    @default_color = [0, 0, 0]
    @selected_color = [255, 255, 255]
    @font_size = 24
    @selected_index = 0
    @x_offset = 25
    @y_offset = 5

    @mouse_position = nil


    @screen = screen

    Rubygame::TTF.setup

    @font = TTF.new font_file, @font_size

    @options = []
    menu.each do |options|
      self.add_option(options)
    end
  end

  def update(ev)
    case ev
      when Rubygame::Events::MouseMoved
        @mouse_position = ev.pos
        # We check if the mouse is colliding with any menu options here, so that our drawing code
        # just knows "given this index, show this one as selected."
        @options.each_with_index do |attributes, index|
          if attributes[:rect] && attributes[:rect].collide_point?(ev.pos[0], ev.pos[1])
            @selected_index = index
          end
        end
      # We track pressed AND released so that if you click, but change your mind you can drag
      # your mouse off and cancel the selection.
      when Rubygame::Events::MousePressed
        @options.each_with_index do |attributes, index|
          if attributes[:rect] && attributes[:rect].collide_point?(ev.pos[0], ev.pos[1])
            @being_pressed = attributes
          end
        end
      when Rubygame::Events::MouseReleased
        if @being_pressed[:rect].collide_point?(ev.pos[0], ev.pos[1])
          @being_pressed[:action][]
        else
          @being_pressed = nil
        end
      when Rubygame::Events::KeyPressed
        case ev.key
          when :up
            if @selected_index > 0
              @selected_index -= 1
            else
              # roll over
              @selected_index = @options.length - 1
            end
          when :down
            if @selected_index < (@options.length - 1)
              @selected_index += 1
            else
              # roll over
              @selected_index = 0
            end
          when :space, :return
            @options[@selected_index][:action][]
        end
    end
  end

  def draw
    @background.blit @screen, [0, 0]
    @options.each_with_index do |menu_item_attributes, index|
      # Index based select
      color = index == @selected_index ? menu_item_attributes[:selected_color] : menu_item_attributes[:default_color]
      menu_item = @font.render menu_item_attributes[:title], true, color
      position = [menu_item_attributes[:x_offset] + @x_offset, menu_item_attributes[:y_offset] + @y_offset + menu_item.h * (index + 1)]
      menu_item_attributes[:rect] = menu_item.blit(@screen, position)
    end
  end

  protected

  def add_option(options)
    menu_item_attributes = {
      :x_offset => 0,
      :y_offset => 0,
      :default_color => @default_color,
      :selected_color => @selected_color,
    }.merge!(options)
    @options << menu_item_attributes
  end
end

usage.rb

@font_path = File.expand_path(File.join(File.dirname(__FILE__), '../artwork/abelbecker.ttf'))
@menu = Menu.new(
  @screen,
  @font_path,
  @background,
  [
    {:title => "New Game", :action => method(:new_game)},
    {:title => "Continue", :action => method(:continue)},
    {:title => "Exit", :action => method(:exit)},
  ])

@queue.each do |e| @main_menu.update(e) end
@main_menu.draw
@screen.flip