large gnome::canvas problem

[hagi]

hi,

I have a little problem with displaying items in 'big' canvas, test
code:

#!/usr/bin/env ruby

require 'gnomecanvas2'

window = Gtk::Window.new
window.signal_connect("delete_event") do |widget, event|
Gtk::main_quit
end

box = Gtk::VBox.new(false, 4)
window.add(box)

points = [[200, 10], [79800, 190]]

canvas = Gnome::Canvas.new(true)
canvas.set_size_request(500, 200)
canvas.set_scroll_region(0, 0, 80000, 200);
canvas.center_scroll_region = false
canvas.show
Gnome::CanvasLine.new(canvas.root,
{oints => points,
:fill_color_rgba => 0x00ff00ff,
:width_pixels => 10.0})
box.pack_start(canvas)

scroll = Gtk::HScrollbar.new(canvas.hadjustment)
scroll.show
box.pack_start(scroll)

adj = canvas.hadjustment

canvas = Gnome::Canvas.new(false)
canvas.set_size_request(500, 200)
canvas.set_scroll_region(0, 0, 80000, 200);
canvas.center_scroll_region = false
canvas.show
canvas.hadjustment = adj

Gnome::CanvasLine.new(canvas.root,
{oints => points,
:fill_color_rgba => 0xff000000,
:width_pixels => 10.0})
box.pack_start(canvas)

box.show
window.show

Gtk.main


the green line is in 'antialiased' canvas and looks good, red which is
not antialiased looks strange, in fact I,ve got two lines or three
(different look on different systems)

any idea?

thanks in advance

disclaimer: beginer in ruby and gtk, bad english