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

VERSION
    Version 0.4

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
        [email protected]

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.