Alexander Yezhov

NAME

Imager::Filter::Autocrop - Automatic crop filter for Imager.

VERSION

Version 1.23

SYNOPSIS

    use Imager;
    use Imager::Filter::Autocrop;

    my $img = Imager->new();
    $img->read(file => 'image.jpg');
    $img->filter(type => 'autocrop') or die $img->errstr;

DESCRIPTION

This module extends Imager functionality with the autocrop filter, similar to ImageMagick and GraphicsMagick "trim". It does have a few additional features as well, such as support for the border or detection-only mode. The distribution also includes a command-line script autocrop.pl.

Note: If the image looks blank (whether genuinely or because of the 'fuzz' parameter), or if there is nothing to crop, then the filter call will return false and the 'errstr' method will return appropriate message.

NAME OVERRIDE

You can change the name under which the filter is registered, by specifying it in 'use' directive. For example, to change the name to 'trim' from the default 'autocrop':

    use Imager;
    use Imager::Filter::Autocrop 'trim';

    $img->filter(type => 'trim') or die $img->errstr;

PARAMETERS

color

By default the color of the top left pixel is used for cropping. You can explicitly specify one though, by either providing the '#RRGGBB' value or passing an object of Imager::Color class or its subclass.

    # The following two calls are identical. 
    $img->filter(type => 'autocrop', color => "#FFFFFF");
    $img->filter(type => 'autocrop', color => Imager::Color->new(255, 255, 255));
fuzz

You can specify the deviation for the color value (for all RGB channels or the main channel if it is a greyscale image), by using the 'fuzz' parameter. All image colors within the range would be treated as matching candidates for cropping.

    $img->filter(type => 'autocrop', fuzz => 20);
border

You can specify the border around the image for cropping. If the cropping area with the border is identical to the original image height and width, then no actual cropping will be done.

    $img->filter(type => 'autocrop', border => 10);
detect

Finally, you can just detect the cropping area by passing a hash reference as a 'detect' parameter. On success, your hash will be set with left, right, top and bottom keys and appropriate values. Please note that if the 'border' parameter is used, the detected area values will be adjusted appropriately.

    my %points = ();
    $img->filter(type => 'autocrop', detect => \%points);

SEE ALSO

http://search.cpan.org/perldoc?Imager

AUTHOR

Alexander Yezhov, <leader at cpan.org> Domain Knowledge Ltd. https://do-know.com/

BUGS

Please report any bugs or feature requests to bug-imager-filter-autocrop at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Imager-Filter-Autocrop. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Imager::Filter::Autocrop

You can also look for information at:

LICENSE AND COPYRIGHT

Copyright 2016 Alexander Yezhov.

This program is free software; you can redistribute it and/or modify it under the terms of the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.

If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.