Gimp::Feature - check for specific features to be present before registering the script.

Gimp documentation Contained in the Gimp distribution.

Index

Code Index:

NAME

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Gimp::Feature - check for specific features to be present before registering the script.

SYNOPSIS

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  use Gimp::Feature;

or

  use Gimp::Feature qw(feature1 feature2 ...);

DESCRIPTION

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This module can be used to check for specific features to be present. This can be used to deny running the script when neccessary features are not present. While some features can be checked for at any time, the Gimp::Fu module offers a nicer way to check for them.

gtk

checks for the presence of the gtk interface module.

gtk-1.1, gtk-1.2

checks for the presence of gtk-1.1 (1.2) or higher.

perl-5.005

checks for perl version 5.005 or higher.

pdl

checks for the presence of a suitable version of PDL (>=1.9906).

gnome

checks for the presence of the Gnome-Perl module.

gtkxmhtl

checks for the presence of the Gtk::XmHTML module.

unix

checks wether the script runs on a unix-like operating system. At the moment, this is every system except windows, macos, os2 and vms.

persistency

checks wether the Gimp::Data module (Gimp::Data) can handle complex persistent data structures, i.e. perl references in addition to plain strings.

The following features can only be checked after Gimp-main> has been called (usually found in the form exit main). See Gimp::Fu on how to check for these.

gimp-1.1, gimp-1.2

checks for the presense of gimp in at least version 1.1 (1.2).

FUNCTIONS

present(feature)

Checks for the presense of the single feature given as the argument. Returns true if the feature is present, false otherwise.

need(feature,[function-name])

Require a specific feature. If the required feature is not present the program will exit gracefully, logging an appropriate message. You can optionally supply a function name to further specify the place where this feature was missing.

This is the function used when importing symbols from the module.

missing(feature-description,[function-name])

Indicates that a generic feature (described by the first argument) is missing. A function name can further be specified. This function will log the given message and exit gracefully.

describe(feature)

Returns a string describing the given feature in more detail, or undef if there is no description for this feature.

list()

Returns a list of features that can be checked for. This list might not be complete.

AUTHOR

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Marc Lehmann <pcg@goof.com>

SEE ALSO

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perl(1), Gimp(1).

Gimp documentation Contained in the Gimp distribution. 
package Gimp::Feature;

require Exporter;

@ISA=(Exporter);
@EXPORT = ();

my $gtk;

sub _check_gtk {
   unless (defined $gtk) {
      eval { require Gtk }; $gtk = $@ eq "" && $Gtk::VERSION>=0.5;
   }
   $gtk;

}

my %description = (
   'gtk'        => 'the gtk perl module',
   'gtk-1.1'    => 'gtk+ version 1.1 or higher',
   'gtk-1.2'    => 'gtk+ version 1.2 or higher',
   'gtk-1.3'    => 'gtk+ version 1.3 or higher',
   'gtk-1.4'    => 'gtk+ version 1.4 or higher',

   'gimp-1.1'   => 'gimp version 1.1 or higher',
   'gimp-1.2'   => 'gimp version 1.2 or higher',
   'gimp-1.3'   => 'gimp version 1.3 or higher',

   'perl-5.005' => 'perl version 5.005 or higher',
   'pdl'        => 'compiled-in PDL support',
   'gnome'      => 'the gnome perl module',
   'gtkxmhtml'  => 'the Gtk::XmHTML module',
   'dumper'     => 'the Data::Dumper module',
   'never'      => '(for testing, will never be present)',
   'unix'	=> 'a unix-like operating system',
   'persistency'=> 'Gimp::Data can handle persistency',
);

sub import {
   my $pkg = shift;
   my $feature;

   local $Gimp::in_query=(@ARGV and $ARGV[0] eq "-gimp");
   while(defined (my $feature = shift)) {
      $feature=~s/^://;
      need($feature);
   }
}

sub describe {
   $description{$_[0]};
}

sub Gimp::Feature::list {
   keys %description;
}

sub present {
   local $_ = shift;

   if ($_ eq "gtk") {
      _check_gtk;
   } elsif ($_ eq "gtk-1.1") {
      _check_gtk and (Gtk->major_version==1 && Gtk->minor_version>=1) || Gtk->major_version>1;
   } elsif ($_ eq "gtk-1.2") {
      _check_gtk and (Gtk->major_version==1 && Gtk->minor_version>=2) || Gtk->major_version>1;
   } elsif ($_ eq "gtk-1.3") {
      _check_gtk and (Gtk->major_version==1 && Gtk->minor_version>=3) || Gtk->major_version>1;
   } elsif ($_ eq "gtk-1.4") {
      _check_gtk and (Gtk->major_version==1 && Gtk->minor_version>=4) || Gtk->major_version>1;

   } elsif ($_ eq "gimp-1.1") {
      (Gimp->major_version==1 && Gimp->minor_version>=1) || Gimp->major_version>1;
   } elsif ($_ eq "gimp-1.2") {
      (Gimp->major_version==1 && Gimp->minor_version>=2) || Gimp->major_version>1;
   } elsif ($_ eq "gimp-1.3") {
      (Gimp->major_version==1 && Gimp->minor_version>=3) || Gimp->major_version>1;

   } elsif ($_ eq "perl-5.005") {
      $] >= 5.005;
   } elsif ($_ eq "pdl") {
      require Gimp::Config; $Gimp::Config{DEFINE1} =~ /HAVE_PDL/;
   } elsif ($_ eq "gnome") {
      eval { require Gnome }; $@ eq "";
   } elsif ($_ eq "gtkxmhtml") {
      eval { require Gtk::XmHTML }; $@ eq "";
   } elsif ($_ eq "dumper") {
      eval { require Data::Dumper }; $@ eq "";
   } elsif ($_ eq "persistency") {
      eval { require Data::Dumper }; $@ eq "";
   } elsif ($_ eq "unix") {
      !{
         MacOS		=> 1,
         MSWin32	=> 1,
         dos		=> 1,
         MSDOS		=> 1,
         os2		=> 1,
         VMS		=> 1,
         RISCOS		=> 1,
         AmigaOS	=> 1,
         utwin		=> 1,
       }->{$^O};
   } elsif ($_ eq "never") {
      0;
   } else {
      require Gimp;
      Gimp::logger(message => "unimplemented requirement '$_' (failed)");
      0;
   }
}

sub _missing {
   my ($msg,$function)=@_;
   require Gimp;
   Gimp::logger(message => "$_[0] is required but not found", function => $function);
   Gimp::initialized() ? Gimp::quiet_die() : Gimp::xs_exit(Gimp::quiet_main());
}

sub missing {
   local $Gimp::in_query=1;
   &_missing;
}

sub need {
   my ($feature,$function)=@_;
   _missing($description{$feature},$function) unless present $feature;
}

1;
__END__