That api has been removed (it was really only useful for a small set of games). If you want to create gridlines try this:
def gridlines!
args = $gtk.args
args.state.show_gridlines = !$gtk.args.state.show_gridlines
if args.state.show_gridlines && args.outputs.static_lines.length == 0
args.outputs.static_lines << 80.times.map do |i|
[
[i * 16, 0, i * 16, 720, 128, 128, 128],
[ 0, i * 16, 1280, i * 16, 128, 128, 128],
]
end
elsif !args.state.show_gridlines
args.outputs.static_lines.clear
end
end
Then you can bring up the heads up display and run grindlines!
and press enter.
Also! Come to the Discord channel if you have questions (lots of people there to help): http://discord.dragonruby.org.