require 'tkmove4.rb'
include TestBed

def get_item_coords( item )
  coord = item.coords
  coord_array = []
  x = coord.shift
  y = coord.shift
  while x != nil
    coord_array.push( [x.to_f, y.to_f] )
    x = coord.shift
    y = coord.shift
  end
  coord_array
end
def min_max( coord_array, index )
  temp = coord_array.collect{|c| c[index]}
  [ temp.min, temp.max ]
end
def mirror( item, index )
  coords_array = get_item_coords( item )
  min, max = min_max( coords_array, index)
  axis = ( min + max )
  temp = coords_array.collect{|c| c[index] = axis - c[index]; c }
  eval "item.coords( #{temp.join(',')} )" 
end
def mirror_at_cursor( canvas, index )
  item = canvas.find_withtag('current').shift
  mirror( item, index )
end

c = TkCanvas.new.pack
testbed(c)
TkButton.new(nil, 'text'=>'mirror', 'command'=>proc{
  TkRoot.new.cursor('hand2')
  c.bind('1', proc{})
  c.bind('B1-Motion', proc{})
  c.itembind('item', '1', proc{ mirror_at_cursor( c, 0 ) })
  }).pack
Tk.mainloop