require 'rubygems'
require 'wx'

include Wx

class RegionTest < App
  def on_init
    @frame = Wx::Frame.new( nil , -1 , "Test Frame", DEFAULT_POSITION, Size.new(400, 500));
    @x = 10
    @y = 10

    Timer.after(1000){@frame.paint{|dc|
        dc.draw_rectangle(10, 10, 300, 200)
      }}

    @frame.show

    evt_key_down() {|event|
      refreshRectangle {
        case event.get_key_code
        when 315 : @y -= 10
        when 314 : @x -= 10
        when 316 : @x += 10
        when 317 : @y += 10
        end
      }
    }

  end
  
  def refreshRectangle
    @frame.paint{|dc|
      clearRectangle(dc)
      yield
      drawRectangle(dc)
    }
  end

  def clearRectangle(dc)
    region = Region.new(@x,@y,20,20)
    dc.set_background(Wx::WHITE_BRUSH)
    dc.set_clipping_region(region)
    dc.clear
    dc.destroy_clipping_region
  end

  def drawRectangle(dc)
    dc.destroy_clipping_region
    dc.set_brush(Wx::GREEN_BRUSH)
    dc.set_pen(Wx::BLACK_PEN)
    dc.draw_rectangle(@x, @y, 20, 20)
  end
  
  main = RegionTest.new
  main.main_loop
end