Viewing file:  hering.pl (1.15 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
#!/usr/bin/perl
use strict;
use warnings;
use Cairo;
use constant
{
WIDTH => 300,
HEIGHT => 600,
LINES => 32,
M_PI_2 => 3.14159265 / 2.0,
};
use constant
{
MAX_THETA => (.80 * M_PI_2),
};
use constant
{
THETA_INC => (2.0 * MAX_THETA / (LINES-1)),
};
{
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);
$cr->fill;
draw_hering ($cr, WIDTH, HEIGHT);
$cr->show_page;
$surf->write_to_png ($out);
}
sub draw_hering
{
my ($cr, $width, $height) = @_;
$cr->set_source_rgb (0, 0, 0);
$cr->set_line_width (2.0);
$cr->save;
{
$cr->translate ($width / 2, $height / 2);
$cr->rotate (MAX_THETA);
for (my $i=0; $i < LINES; $i++)
{
$cr->move_to (-2 * $width, 0);
$cr->line_to (2 * $width, 0);
$cr->stroke;
$cr->rotate (- THETA_INC);
}
}
$cr->restore;
$cr->set_line_width (6);
$cr->set_source_rgb (1, 0, 0);
$cr->move_to ($width / 4, 0);
$cr->rel_line_to (0, $height);
$cr->stroke;
$cr->move_to (3 * $width / 4, 0);
$cr->rel_line_to (0, $height);
$cr->stroke;
}
|