Tobias Leich
and 1 contributors

NAME

Alien::PNG - building, finding and using PNG binaries

VERSION

Version 0.1

SYNOPSIS

Alien::PNG tries (in given order) during its installation:

  • Locate an already installed PNG via 'libpng-config' script.

  • Check for PNG libs in directory specified by PNG_INST_DIR variable. In this case the module performs PNG library detection via '$PNG_INST_DIR/bin/libpng-config' script.

  • Download prebuilt PNG binaries (if available for your platform).

  • Build PNG binaries from source codes (if possible on your system).

Later you can use Alien::PNG in your module that needs to link agains PNG and/or related libraries like this:

    # Sample Makefile.pl
    use ExtUtils::MakeMaker;
    use Alien::PNG;

    WriteMakefile(
      NAME         => 'Any::PNG::Module',
      VERSION_FROM => 'lib/Any/PNG/Module.pm',
      LIBS         => Alien::PNG->config('libs', [-lAdd_Lib]),
      INC          => Alien::PNG->config('cflags'),
      # + additional params
    );

DESCRIPTION

Please see Alien for the manifest of the Alien namespace.

In short Alien::PNG can be used to detect and get configuration settings from an installed PNG and related libraries. Based on your platform it offers the possibility to download and install prebuilt binaries or to build PNG & co. from source codes.

The important facts:

  • The module does not modify in any way the already existing PNG installation on your system.

  • If you reinstall PNG libs on your system you do not need to reinstall Alien::PNG (providing that you use the same directory for the new installation).

  • The prebuild binaries and/or binaries built from sources are always installed into perl module's 'share' directory.

  • If you use prebuild binaries and/or binaries built from sources it happens that some of the dynamic libraries (*.so, *.dll) will not automaticly loadable as they will be stored somewhere under perl module's 'share' directory. To handle this scenario Alien::PNG offers some special functionality (see below).

METHODS

config()

This function is the main public interface to this module. Basic functionality works in a very similar maner to 'libpng-config' script:

    Alien::PNG->config('prefix');   # gives the same string as 'libpng-config --prefix'
    Alien::PNG->config('version');  # gives the same string as 'libpng-config --version'
    Alien::PNG->config('libs');     # gives the same string as 'libpng-config --libs'
    Alien::PNG->config('cflags');   # gives the same string as 'libpng-config --cflags'

On top of that this function supports special parameters:

    Alien::PNG->config('ld_shared_libs');

Returns a list of full paths to shared libraries (*.so, *.dll) that will be required for running the resulting binaries you have linked with PNG libs.

    Alien::PNG->config('ld_paths');

Returns a list of full paths to directories with shared libraries (*.so, *.dll) that will be required for running the resulting binaries you have linked with PNG libs.

    Alien::PNG->config('ld_shlib_map');

Returns a reference to hash of value pairs '<libnick>' => '<full_path_to_shlib'>, where '<libnick>' is shortname for PNG related library like: PNG.

NOTE: config('ld_<something>') return an empty list/hash if you have decided to use PNG libraries already installed on your system. This concerns 'libpng-config' detection and detection via '$PNG_INST_DIR/bin/libpng-config'.

check_header()

This function checks the availability of given header(s) when using compiler options provided by "Alien::PNG->config('cflags')".

    Alien::PNG->check_header('png.h');
    Alien::PNG->check_header('png.h', 'pngconf.h');

Returns 1 if all given headers are available, 0 otherwise.

get_header_version()

Tries to find a header file specified as a param in PNG prefix direcotry and based on "#define" macros inside this header file tries to get a version triplet.

    Alien::PNG->get_header_version('png.h');

Returns string like '1.2.3' or undef if not able to find and parse version info.

BUGS

Please post issues and bugs at http://rt.cpan.org/NoAuth/Bugs.html?Dist=Alien-PNG

AUTHOR

    Tobias Leich
    CPAN ID: FROGGS
    FROGGS@cpan.org

ACKNOWLEDGEMENTS

    This module is based on Alien::SDL, so in fact the credits has to be given to these guys.
    kmx - complete redesign between versions 0.7.x and 0.8.x

COPYRIGHT

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.