Simple Loading Bar

#== Szyu Scripts presents =====================================================
# * Szyu Scripts' Simple Loading Bar
#   Version 1.0
#   by Szyu
#
#== About =====================================================================
# * This script adds a pseudo loading bar/screen to your game.
#
#== How to Use ================================================================
# * Where you want to use the loading bar, create initiate a new object from
#   Window_LoadingBar:
#   @window_loading_bar = Window_LoadingBar.new((Graphics.width-120)/2,
#         (Graphics.height-48)/2,120,48,method(:on_finished))
#
# * In the on_finished method, dispose of the object like
#   def on_finished
#     @window_loading_bar.close.dispose
#     @window_loading_bar = nil
#     # do other stuff here when finished loading
#   end
#
# * You can adjust the speed of the loading bar by setting the progress_speed:
#   @window_loading_bar.progress_speed = x # default is 2
#
#== Terms of Use ==============================================================
# * You are free to use this script for commercial and non-commercial projects.
#   However I'd like you to inform me of the projects you are planning to use it
#   in, so I can keep track of where my scripts are used.
#
#== Import ====================================================================
$imported = {} if $imported.nil?
$imported["SZ_LoadingBar"] = true
#==============================================================================
#==============================================================================
# ** Window_Loading
#==============================================================================
class Window_LoadingBar < Window_Base
  attr_accessor :progress
  attr_reader :finished
  #--------------------------------------------------------------------------
  # * Initialize
  #--------------------------------------------------------------------------
  def initialize(x,y,w, h, on_finished_prc)
    super(x,y,w,h)
    @progress = 0
    @finished = false
    @on_finished = on_finished_prc
    @progress_speed = 2
    refresh
  end
  #--------------------------------------------------------------------------
  # * Set Progress Speed
  #--------------------------------------------------------------------------
  def progress_speed=(speed)
    @progress_speed = speed
  end
  #--------------------------------------------------------------------------
  # * Update
  #--------------------------------------------------------------------------
  def update
    super
    return if @finished
    @progress += @progress_speed
    refresh
    if @progress >= 100
      @finished = true
      @on_finished.call if @on_finished
    end
  end
  #--------------------------------------------------------------------------
  # * Refresh
  #--------------------------------------------------------------------------
  def refresh
    contents.clear
    h = line_height
    draw_loading_gauge(0,(contents.height-h)/2,width,h, @progress.to_f/100, hp_gauge_color1, hp_gauge_color2)
  end
  #--------------------------------------------------------------------------
  # * Draw Loading Gauge
  #--------------------------------------------------------------------------
  def draw_loading_gauge(x, y, width, height, rate, color1, color2)
    fill_w = (width * rate).to_i
    gauge_y = y
    contents.fill_rect(x, gauge_y, width, line_height, gauge_back_color)
    contents.gradient_fill_rect(x, gauge_y, fill_w, line_height, color1, color2)
  end
end