=head1 NAME

pdflink - insert document links in PDF

=head1 SYNOPSIS

  pdflink [options] pdf-file [csv-file]

  pdflink [options] --targets=file1;file2 pdf-file [pdf-file ...]

Inserts document links in PDF

 Options:
    --output=XXX	name of the new PDF (default __new__.pdf)
    --embed		embed the data files instead of linking
    --attach		attach the data files instead of linking
    --xpos=NN		X-position for links
    --ypos=NN		Y-position for links relative to top
    --iconsize=NN	size of the icons, default 50
    --icons=type=XXX	add icon image XXX for this type
    --padding=NN	padding between icons, default 0
    --vertical		stacks icons vertically
    --border		draws a border around the links
    --gfunder		draws the images behind the page
    --targets=XXX	specifies the target(s) to link to
    --ident		shows identification
    --help		shows a brief help message and exits
    --man               shows full documentation and exits
    --verbose		provides more verbose information

=head1 DESCRIPTION

When invoked without a B<--targets> option, this program will process
the PDF document using the associated CSV as table of contents.

For every item in the PDF that has one or more additional files (files
with the same name as the title, but differing extensions), clickable
icons are added to the first page of the item. When clicked in a
suitable PDF viewing tool, the corrresponding file will be activated.

For example, if the CSV contains

  title;pages;
  Blue Moon;24;

And the following files are present in the current directory

  Blue Moon.html
  Blue Moon.mscz

Then two clickable icons will be added to page 24 of the document,
leading to these two files.

Upon completion, the updated PDF is written out under the specified name.

When invoked with the B<--targets> option, all specified PDF files get
links inserted to the targets on the first page. If there is only one
PDF file you can use the B<--pdf> option to designate the name of the
new PDF document, otherwise all PDF files are updated (rewritten.

=head1 OPTIONS

Note that all sizes and dimensions are in I<points> (72 points per inch).

=over 8

=item B<--pdf=>I<XXX>

Specifies the updated PDF to be written.

=item B<--embed>

Normally links are inserted into the PDF document that point to files
on disk. To use the links from the PDF document, the target files must
exist on disk.

With B<--embed>, the target files are embedded (as file attachments)
to the PDF document. The resultant PDF document will be usable on its
own, no other files needed.

=item B<--attach>

This is similar to B<--embed>, but the files are attached to the PDF
document and no icons are placed on the pages.

=item B<--all>

Normally, only files with known types (extensions) are taken into
account. Currently, these are C<html> for iRealPro, C<mscz> for
MuseScore, C<sib> for Sibelius, C<mxl> and C<musicxml> for MusicXML,
C<abc> for ABC and C<XML> for generic XML documents.

With B<--all>, all files that have matching names will be processed.
However, files with unknown extensions will get a neutral document
icon.

=item B<--xpos=>I<NN>

Horizontal position of the icons.

If the value is positive, icon placement starts relative to the left
side of the page.

If the value is negative, icon placement starts relative to the right
side of the page.

Default is 0 (zero); icon placement begins against the left side of
the page.

Icons are always placed from the outside of the page towards the
inner side.

An I<xpos> value may also be specified in the CSV file, in a column
with title C<xpos>. If present, this value is added to position
resulting from the command line / default values.

=item B<--ypos=>I<NN>

If the value is positive, icon placement starts relative to the top
of the page.

If the value is negative, icon placement starts relative to the bottom
of the page.

Default is 0 (zero); icon placement begins against the top of the
page.

Icons are always placed from the outside of the page towards the
inner side.

An I<ypos> offset value may also be specified in the CSV file, in a
column with title C<ypos>. If present, this value is added to position
resulting from the command line / default values. This is especially
useful if there are songs in the PDF that do not start at the top of
the page, e.g., when there are multiple songs on a single page.

=item B<--iconsize=>I<NN>

Desired size of the link icons. Default is 50.

=item B<--padding=>I<NN>

Space between icons. Default is to place the icons adjacent to each
other.

=item B<--vertical>

Stacks the icons vertically.

=item B<--border>

Requests a border to be drawn around the links.

Borders are always drawn for links without icons.

=item B<--gfunder>

Drawing the icon images uses the page transformations in effect at the
end of the page. If these were not neatly restored, the graphics may
be misplaced/scaled/flipped.

By using B<--gfunder>, the images are placed behind the page
but this only works for transparent pages.

This option is only relevant when adding links to external files. With
B<--embed> the problem does not occur.

=item B<--targets=>I<FILE1> [ B<;> I<FILE2> ... ]

Explicitly specifies the target files to link to. In this case no CSV
is processed and the input PDF(s) are updated (rewritten) unless
B<--pdf> is used to designate the output PDF name.

=item B<--help>

Prints a brief help message and exits.

=item B<--man>

Prints the manual page and exits.

=item B<--ident>

Prints program identification.

=item B<--version>

Prints program identification and exits.

=item B<--verbose>

Provides more verbose information.

=item I<directory>

The directory to process. Defaults to the current directory.

=back

=head1 ICONS

B<pdflink> has a number of icons built-in for common file types.
Associations between a filename extension and an icon can be made with
the B<--icons> command line option.

For example,

  --icons=pdf=builtin:PDF

This will associate the built-in icon PDF with filename extension C<pdf>.

Alternatively, an image file may be specified to add user defined icons.

  --icons=pdf=builtin:myicons/pdficon.png

The following icons are built-in. By default, only MuseScore and
iRealPro icons are associated and all other filename extensions will
be skipped. When pdflink is run with command line option B<--all>, all
built-in icons will be associated and all matching files will get
linked.

=over

=item PDF

Associated to filename extension C<pdf> (generic PDF document).

=item PNG

Associated to filename extension C<png> (PNG image).

=item JPG

Associated to filename extensions C<jpg> and C<jpeg> (JPG image).

=item MuseScore

Associated to filename extension C<mscz> (MuseScore document).

=item iRealPro

Associated to filename extension C<html> (iRealPro link in HTML document).

While technically this is wrong, this is the way iRealPro data is
handled on Android and iPad.

=item BandInABox

Associated to filename extensions C<mgu>, C<mg1> and so on (Band-In-A-Box document).

=item MXL

Associated with filename extension C<xml> and C<musicxml> (MusicXML).

=item XML

Associated with filename extension C<xml> (generic XML document).

=item Document

Fallback icon for unknown filename extensions.

=item Border

Alternative fallback icon for unknown filename extensions.

=back

=head1 LIMITATIONS

Some PDF files cannot be processed. If this happens, try converting
the PDF to PDF-1.4 or PDF/A.

Files with extension B<html> are assumed to be iRealPro files and will
get the iRealPro icon.

Unknown extensions will get an empty square box instead of an icon.

Since colon C<:> and slash C</> are not allowed in file names, they
are replaced with C<@> characters.

If the icons come out at the wrong place or upside down, try
B<--gfunder>.

=head1 AUTHOR

Johan Vromans E<lt>jvromans@squirrel.nlE<gt>

=head1 COPYRIGHT

Copyright 2016,2020 Johan Vromans. All rights reserved.

This module is free software. You can redistribute it and/or
modify it under the terms of the Artistic License 2.0.

This program is distributed in the hope that it will be useful,
but without any warranty; without even the implied warranty of
merchantability or fitness for a particular purpose.

=head1 AUTHOR

Johan Vromans C<< <jv at CPAN dot org > >>

=head1 SUPPORT

PDFlink development is hosted on GitHub, repository
L<https://github.com/sciurius/pdflink>.

Please report any bugs or feature requests to the GitHub issue tracker,
L<https://github.com/sciurius/pdflink/issues>.

