#!/usr/bin/perl
use strict;
use warnings;
use Cairo;
use constant
{
WIDTH => 600,
HEIGHT => 600,
};
{
my $surf = Cairo::ImageSurface->create ('argb32', WIDTH, HEIGHT);
my $cr = Cairo::Context->create ($surf);
$0 =~ /(.*)\.pl/;
my $out = "$1.png";
$cr->rectangle (0, 0, WIDTH, HEIGHT);
$cr->set_source_rgb (1, 1, 1);
$cr->fill;
draw_caps_joins ($cr, WIDTH, HEIGHT);
$cr->show_page;
$surf->write_to_png ($out);
}
sub stroke_v_twice
{
my ($cr, $width, $height) = @_;
$cr->move_to (0, 0);
$cr->rel_line_to ($width / 2, $height / 2);
$cr->rel_line_to ($width / 2, - $height / 2);
$cr->save;
$cr->stroke;
$cr->restore;
$cr->save;
{
$cr->set_line_width (2.0);
$cr->set_line_cap ('butt');
$cr->set_source_rgb (1, 1, 1);
$cr->stroke;
}
$cr->restore;
$cr->new_path;
}
sub draw_caps_joins
{
my ($cr, $width, $height) = @_;
my $line_width = $height / 12 & (~1);
$cr->set_line_width ($line_width);
$cr->set_source_rgb (0, 0, 0);
$cr->translate ($line_width, $line_width);
$width -= 2 * $line_width;
$cr->set_line_join ('bevel');
$cr->set_line_cap ('butt');
stroke_v_twice ($cr, $width, $height);
$cr->translate (0, $height / 4 - $line_width);
$cr->set_line_join ('miter');
$cr->set_line_cap ('square');
stroke_v_twice ($cr, $width, $height);
$cr->translate (0, $height / 4 - $line_width);
$cr->set_line_join ('round');
$cr->set_line_cap ('round');
stroke_v_twice ($cr, $width, $height);
}