=head1 NAME

UI::Dialog::Backend::XOSD - backend for the osd_cat(1).

=head1 SYNOPSIS

  use UI::Dialog::Backend::XOSD;
  my $xosd = new UI::Dialog::Backend::XOSD ();
  $xosd->line( text => "Something to display...");

=head1 ABSTRACT

UI::Dialog::Backend::XOSD is an OOPerl wrapper for the osd_cat(1)
program.

=head1 DESCRIPTION

Use this module to present feedback to the end user via an on-screen
display (like an on-screen TV volume meter).  When you use any of the
UI::Dialog meta classes (UI::Dialog, UI::Dialog::GNOME, etc.) access
to this backend is provided via the $d->xosd method. ie: replace $xosd
with $d->xosd in the synopsis example (provided you made $d with
something like my $d = new UI::Dialog...). Also, UI::Dialog (and
friends) only load this module when you first use the $d->xosd method
(this may silently fail, but you can test by ref() for success).

=head1 EXPORT

=over 2

None

=back

=head1 INHERITS

=over 2

UI::Dialog::Backend

=back

=head1 CONSTRUCTOR

=head2 new( @options )

=over 4

=item EXAMPLE

=over 6

 my $xosd = new UI::Dialog::Backend::XOSD ( );

=back

=item DESCRIPTION

=over 6

This is the Class Constructor method. It accepts a list of key => value pairs
and uses them as the defaults when interacting with the various widgets. All
methods accept the same arguments as new() except that the arguments passed to
the methods are temporarily used instead of making them the default as the
new() method does. In the case of the 'wait' option, any (non-zero) value enables
the option as it's a switch and not a string argument.

=back

=item RETURNS

=over 6

A blessed object reference of the UI::Dialog::Backend::XOSD class.

=back

=item OPTIONS

The (...)'s after each option indicate the default for the option. An * denotes
support by all the widget methods on a per-use policy defaulting to the
values decided during object creation.

=over 6

=item B<offset = \d+> (0) *

=item B<align = \w+> ('left') *

=item B<indent = \d+> (0) *

=item B<font = "x-font-string"> ('fixed') *

=item B<colour = \w+> ('red') *

=item B<delay = \d+> (5) *

=item B<lines = \d+> (5) *

=item B<shadow = \d+> (0) *

=item B<age = \d+> (0) *

=item B<wait = 0,1> (0) *

=back

=back

=head1 METHODS

=head2 line( )

=over 4

=item EXAMPLE

=over 6

 $xosd->line( text => "some text to display" );

=back

=item DESCRIPTION

=over 6

Display a simple string on the screen.

=back

=item RETURNS

=over 6

Nothing.

=back

=back

=head2 file( )

=over 4

=item EXAMPLE

=over 6

 $xosd->file( file => "/path/to/a/file" );

=back

=item DESCRIPTION

=over 6

Display a file on the screen.

=back

=item RETURNS

=over 6

Nothing.

=back

=back

=head2 gauge( )

=over 4

=item EXAMPLE

=over 6

 $xosd->gauge( text => "",
               percent => $current_percentage,
               length => 40,
               bar => "-",
               mark => "|" );

=back

=item DESCRIPTION

=over 6

Display a gauge bar with a percentage mark on the screen with an optional
message.

=back

=item RETURNS

=over 6

Nothing.

=back

=back

=head2 display_start( )

=over 4

=item EXAMPLE

=over 6

 $xosd->display_start( );

=back

=item DESCRIPTION

=over 6

Opens a pipe command to the osd_cat(1) program for prolonged interactivity.
This accepts all of the standard options but has nothing else to offer. The
other display_*() methods (detailed below) return zero unless this method has
been used and has created the command pipe.

=back

=item RETURNS

=over 6

TRUE (1) for success and FALSE (0) otherwise.

=back

=back

=head2 display_text( )

=over 4

=item EXAMPLE

=over 6

 $xosd->display_start();
 $xosd->display_text( "Some string to display." );

=back

=item DESCRIPTION

=over 6

Uses the command pipe created by display_start() and prints the first argument
to the screen. This method does not have any options, save the one string
scalar.

=back

=item RETURNS

=over 6

TRUE (1) for success and FALSE (0) otherwise.

=back

=back

=head2 display_gauge( )

=over 4

=item EXAMPLE

=over 6

 $xosd->display_start();
 $xosd->display_gauge( 50, "display an optional text string." );

=back

=item DESCRIPTION

=over 6

Uses the command pipe created by display_start() and prints a gauge identical
to the regular (stand-alone) gauge() method. There are only to accepted
arguments; the desired percentage and an optional text string.

=back

=item RETURNS

=over 6

TRUE (1) for success and FALSE (0) otherwise.

=back

=back

=head2 display_stop( )

=over 4

=item EXAMPLE

=over 6

 $xosd->display_start();
 $xosd->display_text( "about to stop!" );
 $xosd->display_stop();

=back

=item DESCRIPTION

=over 6

This closes the command pipe opened by the display_start() method. This method
takes no arguments and performs only the task for closing and existing
command pipe.

=back

=item RETURNS

=over 6

TRUE (1) for success and FALSE (0) otherwise.

=back

=back

=head1 SEE ALSO

=over 2

=item PERLDOC

 UI::Dialog
 UI::Dialog::Backend

=back

=over 2

=item MAN FILES

osd_cat(1)

=back

=head1 BUGS

Please email the author with any bug reports. Include the name of the
module in the subject line.

=head1 AUTHOR

Kevin C. Krinke, E<lt>kevin@krinke.caE<gt>

=head1 COPYRIGHT AND LICENSE

 Copyright (C) 2004-2016  Kevin C. Krinke <kevin@krinke.ca>

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.

 This library 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.  See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA

=cut