File Coverage

blib/lib/Image/Compare/IMAGE.pm

Criterion	Covered	Total	%
statement	52	52	100.0
branch	5	6	83.3
condition	2	3	66.6
subroutine	12	12	100.0
pod	3	3	100.0
total	74	76	97.3

package Image::Compare::IMAGE;

use warnings;
use strict;

use Imager ':handy';
use Imager::Fountain;

use base qw/Image::Compare::Comparator/;

use constant FILL_IMAGE_CACHE => {};
use constant FILL_IMAGE_WIDTH => 1000;
use constant DEFAULT_COLOR_FOUNTAIN => Imager::Fountain->simple(
	positions => [          0.0,           0.5,           1.0],
	colors    => [NC(255, 0, 0), NC(0, 255, 0), NC(0, 0, 255)],
);
use constant DEFAULT_GREYSCALE_FOUNTAIN => Imager::Fountain->simple(
	positions => [        0.0,               1.0],
	colors    => [NC(0, 0, 0), NC(255, 255, 255)],
);

sub setup {
	my $self = shift;
	$self->SUPER::setup(@_);
	$self->{count} = 0;
	$self->{img} = Imager->new(
		xsize => $_[0]->getwidth(),
		ysize => $_[0]->getheight(),
	);
	# Now we build up our fill image; this is a 1000 x 1 image that is filled
	# using an Imager fountain.  We'll pull pixels from it to put colors into
	# the generated image.
	my $fountain;
	if ($self->{args}) {
		# If there's an argument, it's either a fountain, or it's telling us to use
		# the default color fountain.
		if (ref $self->{args} && $self->{args}->isa('Imager::Fountain')) {
			$fountain = $self->{args};
		}
		else {
			$fountain = DEFAULT_COLOR_FOUNTAIN();
		}
	}
	else {
		# In this case, we use the default greyscale fountain.
		$fountain = DEFAULT_GREYSCALE_FOUNTAIN();
	}
	# Using an object as a hash key stringifies it to its memory location and
	# uses that.  This is suboptimal, but the Imager::Fountain class has no
	# "to_string", so we make do.
	unless (FILL_IMAGE_CACHE()->{$fountain}) {
		my $image = Imager->new(xsize => FILL_IMAGE_WIDTH(), ysize => 1);
		$image->filter(
			type => 'fountain',         segments => $fountain,
			xa   => 0,                  ya       => 0,
			xb   => FILL_IMAGE_WIDTH(), yb       => 0,
		);
		FILL_IMAGE_CACHE()->{$fountain} = $image;
	}
	$self->{fill_image} = FILL_IMAGE_CACHE()->{$fountain};
}

sub accumulate {
	my $self = shift;
	my($pix1, $pix2, $x, $y) = @_;
	my $diff = $self->color_distance($pix1, $pix2);
	# We want to convert from our range of values for $diff (0 .. 441.7) to
	# the range of values of our fill image, which is defined by a constant.
	$diff *= FILL_IMAGE_WIDTH();
	$diff /= 441.7;
	my $color = $self->{fill_image}->getpixel(
		x => $diff,
		y => 0,
	);
	$self->{img}->setpixel(
		x     => $x,
		y     => $y,
		color => $color,
	);
	return undef;
}

sub get_result {
	my $self = shift;
	return $self->{img};
}

1;

__END__