#------------------------------------------------------------------------------
# File:         aspect_ratio.config
#
# Description:  Definition for a Composite "AspectRatio" tag to compute the
#               Storage Aspect Ratio of an image based on the "ImageWidth" and
#               "ImageHeight" tags. Also the Composite "ImageFormat" tag is
#               defined to identify whether the image is in square, portrait
#               or landscape format.
#
# Notes:        See https://en.wikipedia.org/wiki/Aspect_ratio_(image) for a 
#                definition of Aspect Ratio
#
# Examples:     
#    > exiftool -config aspect_ratio.config -imagesize -aspectratio# \
#        -aspectratio -imageformat image_std.jpg
#
#    Image Size                      : 1600x1200
#    Aspect Ratio                    : 1.3333
#    Aspect Ratio                    : 4:3
#    Image Format                    : Std. Landscape
#
#    > exiftool -config aspect_ratio.config -imagesize -aspectratio# \
#        -aspectratio -imageformat image.jpg
#
#    Image Size                      : 2500x1656
#    Aspect Ratio                    : 1.5097
#    Aspect Ratio                    : 625:414
#    Image Format                    : Landscape
#
# Revisions:    2024/02/20 - Christian W. Correa Created
#               2024/02/21 - Added a list of Aspect Ratio standard values to 
#                               the ImageFormat tag
#------------------------------------------------------------------------------

# Compute the Greatest Common Divisor of two numbers
sub gcd {
    my ($A, $B) = @_;
    return 0 == $B
        ? $A
        : gcd($B, $A % $B);
}

%Image::ExifTool::UserDefined = (
    'Image::ExifTool::Composite' => {
        AspectRatio => {
            Require => {
                0 => 'ImageWidth',
                1 => 'ImageHeight',
            },
            ValueConv => 'sprintf("%.4f", $val[0]/$val[1])',
            PrintConv => q{
                my $width = $val[0];
                my $height = $val[1];

                my $gcd = gcd($width, $height);

                my $numerator = $width / $gcd;
                my $denominator = $height / $gcd;
                return "$numerator:$denominator";
            },
        },

        ImageFormat => {
            Require => {
                0 => 'AspectRatio',
            },
            PrintConv => q {
                # Get AR as a fraction
                my $ar = $prt[0];
                my ($ar_width, $ar_height);

                # Define standard AR values
                my @std_square = qw/1:1/;
                my @std_portait = qw/2:3 3:4 3:5 4:5 3:7 5:7 3:8 5:9 8:11 9:13 9:14 9:16 9:17 9:19 10:19 18:35/;
                my @std_landscape = qw/3:2 4:3 5:3 5:4 7:3 7:5 8:3 9:5 11:8 13:9 14:9 16:9 17:9 19:9 19:10 35:18/;

                # Get width and height from ratio
                $ar =~ m/([\.\d]+)[:]([\.\d]+)/i;
                $ar_width = $1;
                $ar_height = $2;

                # Check if AR matches one of the standard values
                # and return Square, Portrait or Landscape
                return 'Square' if /$ar/i ~~ @std_square;
                return 'Std. Portrait' if /$ar/i ~~ @std_portait;
                return 'Std. Landscape' if /$ar/i ~~ @std_landscape;

                # If AR is not a standard value, return Portrait or Landscape
                return 'Portrait' if $ar_width lt $ar_height;
                return 'Landscape' if $ar_width gt $ar_height;

                return undef;
            },
        },
    },
);
1;  #end