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|
package Image::PNM;
use strict;
use warnings;
sub new {
my $class = shift;
my ($data) = @_;
my $self = bless {}, $class;
if (ref $data) {
$self->_parse_string($data);
}
elsif ($data) {
$self->_parse_file($data);
}
else {
$self->{w} = 1;
$self->{h} = 1;
$self->{max} = 1;
$self->{pixels} = [[0]];
}
return $self;
}
sub as_string {
my $self = shift;
my ($format) = @_;
my $method = "_as_string_$format";
die "Unknown format $format"
unless $self->can($method);
return $self->$method;
}
sub width {
my $self = shift;
return $self->{w};
}
sub height {
my $self = shift;
return $self->{h};
}
sub max_pixel_value {
my $self = shift;
return $self->{max};
}
sub pixel {
my $self = shift;
my ($row, $col) = @_;
my $pixel = $self->raw_pixel($row, $col);
return [ map { $_ / $self->{max} } @$pixel ];
}
sub raw_pixel {
my $self = shift;
my ($row, $col) = @_;
my $pixel = $self->{pixels}[$row][$col];
die "invalid pixel location ($row, $col)"
unless defined $pixel;
if (!ref $pixel) {
$pixel = [ $pixel, $pixel, $pixel ];
}
return $pixel;
}
sub _as_string_P3 {
my $self = shift;
my $data = <<HEADER;
P3
$self->{w} $self->{h}
$self->{max}
HEADER
for my $row (@{ $self->{pixels} }) {
$data .= join(' ', map { join(' ', @$_) } @$row) . "\n";
}
return $data;
}
sub _parse_string {
my $self = shift;
my ($string) = @_;
return $self->_parse_pnm(sub {
my ($line, $rest) = split /\n/, $string, 2;
return unless length($line) || length($rest);
$string = $rest;
return "$line\n";
});
}
sub _parse_file {
my $self = shift;
my ($filename) = @_;
open my $fh, '<', $filename
or die "Couldn't open $filename for reading: $!";
return $self->_parse_pnm(sub { scalar <$fh> });
}
sub _parse_pnm {
my $self = shift;
my ($next_line) = @_;
my $next_line_nocomments = sub {
my $line;
while (!length($line)) {
$line = $next_line->();
return unless defined($line);
$line =~ s/#.*//s;
}
return $line;
};
chomp(my $format = $next_line_nocomments->());
chomp(my $dimensions = $next_line_nocomments->());
my ($w, $h) = $dimensions =~ /^([0-9]+)\s+([0-9]+)$/;
die "Invalid dimensions: $dimensions"
unless $w && $h;
$self->{w} = $w;
$self->{h} = $h;
my $method = "_parse_pnm_$format";
die "Don't know how to parse PNM files of format $format"
unless $self->can($method);
return $self->$method($next_line_nocomments);
}
sub _parse_pnm_P3 {
my $self = shift;
my ($next_line) = @_;
chomp (my $max = $next_line->());
die "Invalid max color value: $max"
unless $max =~ /^[0-9]+$/ && $max > 0;
$self->{max} = $max;
my @words;
my $next_word = sub {
if (!@words) {
chomp(my $line = $next_line->());
@words = split ' ', $line;
}
my $word = shift @words;
die "Invalid color: $word" unless $word =~ /^[0-9]+$/;
return $word;
};
$self->{pixels} = [];
for my $i (1..$self->{w}) {
my $row = [];
for my $j (1..$self->{h}) {
push @$row, [
$next_word->(),
$next_word->(),
$next_word->(),
];
}
push @{ $self->{pixels} }, $row;
}
}
1;
|
