#!/usr/local/bin/ruby
require 'xlib'
require 'xlib/motion_notifier.rb'

DIS = Xlib::Display.new

ROOT = DIS.root
ROOT.extend MotionNotifier
PIX = ROOT.new_pixmap ROOT.width/4,ROOT.height/4
DIS.gc.func = Xlib::COPY
area = Xlib::Rect.new ROOT.width-PIX.width,0,PIX.width,PIX.height
ROOT.copy_area PIX,DIS.gc,area

WIN = ROOT.new_window area,true
WIN.title = 'eye'
WIN.border_width = 0
WIN.lower
WIN.show
GC = WIN.new_gc
GC.fg = DIS.alloc_color 'dark green'

start_angle, draw_angle = 0*64, 360*64
size = 48
ex = 0
ey = 0

ROOT.motion_notify_step do |x, y|
  ex = (area.x + x - WIN.x) * (WIN.width  - size) / ROOT.width
  ey = (area.y + y - WIN.y) * (WIN.height - size) / ROOT.height
  PIX.copy_area WIN,GC,PIX.rect
  GC.fill_oval ex,ey,size,size, start_angle,draw_angle
end

WIN.event 'button_press' do exit end

while DIS.event; end