File Coverage

blib/lib/Math/FitRect.pm

Criterion	Covered	Total	%
statement	38	47	80.8
branch	8	16	50.0
condition			n/a
subroutine	8	8	100.0
pod	2	2	100.0
total	56	73	76.7

package Math::FitRect;

$Math::FitRect::VERSION = '0.05';

=head1 NAME

Math::FitRect - Resize one rect in to another while preserving aspect ratio.

=head1 SYNOPSIS

    use Math::FitRect;

    # This will return: {w=>40, h=>20, x=>0, y=>10}
    my $rect = fit_rect( [80,40] => 40 );

    # This will return: {w=>80, h=>40, x=>-19, y=>0}
    my $rect = crop_rect( [80,40] => 40 );

=head1 DESCRIPTION

This module is very simple in its content but can save much time, much like
other simplistic modules like L.  This module is useful for
calculating what size you should resize images as for such things as
thumbnails.

=cut

use strict;
use warnings;

use Carp qw( croak );

use Exporter qw( import );
our @EXPORT_OK = qw(
    fit_rect
    crop_rect
);

=head1 RECTANGLES

Rectangles may be specified in several different forms to fit your needs.

=over

=item A simple scalar integer containg the pixel width/height of a square.

=item An array ref containing the width and height of a rectangle: [$width,$height]

=item A hash ref containg a w (width) and h (height) key: {w=>$width,h=>$height}

=back

=head1 FUNCTIONS

=head2 fit_rect

    # This will return: {w=>40, h=>20, x=>0, y=>10}
    my $rect = fit_rect( [80,40] => 40 );

Takes two rectangles and fits the first one inside the second one.  The rectangle
that will be returned will be a hash ref with a 'w' and 'h' parameter as well
as 'x' and 'y' parameters which will specify any offset.

=cut

sub fit_rect {
    return _calc_rect('fit',@_);
}

=head2 crop_rect

    # This will return: {w=>80, h=>40, x=>-19, y=>0}
    my $rect = crop_rect( [80,40] => 40 );

Like the fit_rect function, crop_rect takes two rectangles as a parameter and it
makes $rect1 completely fill $rect2.  This can mean that the top and bottom or
the left and right get chopped off (cropped).  This method returns a hash ref just
like fit_rect.

=cut

sub crop_rect {
    return _calc_rect('crop',@_);
}

sub _calc_rect {
    my($type,$from,$to) = @_;
    $from = _normalize($from);
    $to = _normalize($to);
    my($w,$h,$x,$y);
    if($type eq 'crop'){ ($to->{r},$from->{r}) = ($from->{r},$to->{r}); }

    if($from->{r} < $to->{r}){
        $w = $from->{w} * ($to->{h}/$from->{h});
        $h = $to->{h};
        $x = ($to->{w}-$w)/2;
        $y = 0;
    }else{
        $h = $from->{h} * ($to->{w}/$from->{w});
        $w = $to->{w};
        $y = ($to->{h}-$h)/2;
        $x = 0;
    }

    return {w=>int($w+0.5),h=>int($h+0.5),x=>int($x+0.5),y=>int($y+0.5)};
}

sub _normalize {
    my $rect = shift;
    my($w,$h,$r);
    if(!ref($rect)){ # square
        $w = $h = $rect;
    }elsif(ref($rect) eq 'HASH'){ # rect hash ref
        $w = $rect->{w};
        $h = $rect->{h};
    }elsif(@$rect==2){ # width, height
        $w = $rect->[0];
        $h = $rect->[1];
    }elsif(@$rect==4){ # x1, y1, x2, y2
        if($rect->[0]<$rect->[2]){ $w=($rect->[2]-$rect->[0])+1; }
        else{ $w=($rect->[0]-$rect->[2])+1; }
        if($rect->[1]<$rect->[3]){ $h=($rect->[3]-$rect->[1])+1; }
        else{ $h=($rect->[1]-$rect->[3])+1; }
    }else{
        croak('Invalid rectangle parameter');
    }
    $r = $w/$h;
    return {w=>$w,h=>$h,r=>$r};
}

1;
__END__