Can't draw lines in GooCanvas - perl

Question

In a Perl/Gtk3 script and using GooCanvas, I can easily draw a rectangle, or an ellipsis, or whatever, but it seems to be impossible to draw a simple line.
Lines are drawn with a call to Goo::CanvasPolyline->new(). The line's coordinates a specified by a call to Goo::CanvasPoints->new(), but that call creates the following error:
GLib-ERROR **: ../../../../glib/gmem.c:105: failed to allocate 18446744069314558208 bytes at /usr/lib/x86_64-linux-gnu/perl5/5.26/Glib/Object/Introspection.pm line 67.
Aborted (core dumped)
I've tried the Perl module Goo::Canvas and the more modern GooCanvas2; both produce the same error.
I wasn't able to find any working code examples; merely the non-working script below, which Google found on $RANDOM_WEBSITE.
#!/usr/bin/perl -w
use strict;
use warnings;
use Gtk3 -init;
Glib::Object::Introspection->setup(basename => 'GooCanvas', version => '2.0', package => 'Goo');
my $window = Gtk3::Window->new('toplevel');
$window->signal_connect('delete_event' => sub { Gtk2->main_quit; });
$window->set_size_request(640, 600);
$window->set_title("Gtk3 GooCanvas with Perl Gobject Introspection");
$window->signal_connect(destroy => sub { Gtk3->main_quit });
my $swin = Gtk3::ScrolledWindow->new;
$swin->set_shadow_type('in');
$window->add($swin);
my $canvas = Goo::Canvas->new; # Gobject Introspection of Gtk3 Goo version
$canvas->set_size_request(800, 650);
$canvas->set_bounds(0, 0, 1000, 1000);
$swin->add($canvas);
my $root = $canvas->get_root_item();
# first point set
my $pts_ref = [50,50,180,120,90,100,50,50];
my $points = Goo::CanvasPoints->new(
$pts_ref,
);
my $line = Goo::CanvasPolyline->new(
'parent' => $root,
'close-path' => 0,
'points' => $points, #in Gtk2 could just use $pts_ref
'stroke-color' => 'black',
'line-width' => 3,
);
my $ellipse = Goo::CanvasEllipse->new(
'parent' => $root,
'center-x' => 20,
'center-y' => 20,
'width' => +60,
'height' => +60,
'stroke-color' => 'goldenrod',
'line-width' => 8,
'fill-color-rgba' => 0x3cb37180,
);
$root->translate(200,200);
$window->show_all();
Gtk3->main;
__END__

Answer 1

my $points = Goo::CanvasPoints->new( $pts_ref );
According to the documentation the constructor should take the number of points to reserve, not the reference to the points array. So you could try:
[...]
# first point set
my $pts_ref = [50,50,180,120,90,100,50,50];
my $num_points = (scalar #$pts_ref)/2;
my $points = Goo::CanvasPoints->new( $num_points );
# Set the points:
my $j = 0;
for my $i (0..($num_points -1)) {
my $x = $pts_ref->[$j];
my $y = $pts_ref->[$j+1];
$points->set_point($i, $x, $y);
$j += 2;
}
[...]