


=encoding UTF-8

=head1 NAME

Image::PNG::Util - manipulate the image data part of PNGs

=head1 SYNOPSIS

    use Image::PNG::Util;

=head1 VERSION

This documents version 0.00_01 of Image-PNG-Util
corresponding to L<git commit 0624f2265b68a7ea27681cfae4e1018ac5c57b8a|https://github.com/benkasminbullock/image-png-util/commit/0624f2265b68a7ea27681cfae4e1018ac5c57b8a> released on Sun Jan 3 15:14:23 2021 +0900.

=head1 DESCRIPTION

This module provides various utilities for manipulating and testing
the image data part of a PNG image. This is a companion module to
L<Image::PNG::Libpng> by the same authors.

=head1 FUNCTIONS

=head2 alpha_used

Is the alpha channel in the image used or is it just completely opaque?

=head2 any2gray8

To be moved here from L<Image::PNG::Libpng>.

=head2 bwpng

    my $png = bwpng (\@rows, sq => 20);

Convert boolean-style data into a black and white PNG.

    bwpng (\@rows, black => '#CFF', white => '#C00');



=head2 rgb2gray

    my $gray_png = rgb2gray ('colorful.png');

Convert RGB to gray.

Options:


grayonly


=head3 See also

L<https://onlinepngtools.com/convert-png-to-grayscale> - converts your
PNG to grayscale via JavaScript. This actually resizes the image to
the size of its box, but you can save the image with the Save
as... link and you get the original size back.

L<https://pinetools.com/grayscale-image>

=head2 rmalpha

Remove the alpha channel of the PNG.

=head2 split_alpha

Copy from IPL.

=head1 DEPENDENCIES

=over

=item L<Image::PNG::Libpng>

=back

=head1 SEE ALSO

See some other things also.



=head1 AUTHOR

Ben Bullock, <bkb@cpan.org>

=head1 COPYRIGHT & LICENCE

This package and associated files are copyright (C) 
2021
Ben Bullock.

You can use, copy, modify and redistribute this package and associated
files under the Perl Artistic Licence or the GNU General Public
Licence.



