# Copyright (C) 2001 Sam Tobin-Hochstadt
# This file is free software; you may copy and/or distribute it with
# or without modifications, as long as this notice is preserved.
# This software is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY, to the extent permitted by law; without even
# the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
# PURPOSE.

# The above license applies to THIS FILE ONLY, the abiword code
# itself may be copied and distributed under the terms of the GNU
# GPL, see COPYING for more details

# Check for libpng
# Supports:
#  *  libpng in system library locations
#  *  Bundled libpng if a directory name argument is passed
#
# Hacked from the abi-xml-parser.m4 code
#
# Usage: 
#  ABI_LIBPNG
# or
#  ABI_LIBPNG(libpng-dir)

AC_DEFUN([ABI_LIBPNG], [

if test "$ABI_NEED_LIBPNG" = "yes"; then

abi_found_libpng="no"

AC_ARG_WITH(libpng-prefix, [  --with-libpng-prefix=PFX   Prefix where libpng is installed (optional)], libpng_prefix="$withval", libpng_prefix="")

# check for library file using prefix
if test "x$libpng_prefix" != "x"; then
    if test -f "$libpng_prefix/lib/libpng.a"; then
           good_libpng_prefix="yes"
       else
           good_libpng_prefix="no"
    fi
fi


# check for shared install, with or without prefix
if test "$good_libpng_prefix" = "yes"; then
    saved_ldflags="$LDFLAGS"
    LDFLAGS="-L$libpng_prefix/lib"
    AC_CHECK_LIB(png,png_create_info_struct,
        abi_libpng_libs="-L$libpng_prefix/lib -lpng" abi_found_libpng="yes")
    LDFLAGS="$saved_ldflags"
else
    if test "$abi_found_libpng" = "no"; then
	echo "checking for libpng"
	AC_CHECK_LIB(png, png_create_info_struct,
           abi_libpng_libs="-lpng" abi_found_libpng="yes")
    fi
fi

# check for header file
if test "$abi_found_libpng" = "yes"; then
    if test "$good_libpng_prefix" = "yes"; then
        if test -f "$libpng_prefix/include/png.h"; then
            abi_found_libpngincs="yes"
        else
            abi_found_libpngincs="no"
        fi
	if test "$abi_found_libpngincs" = "yes"; then
            LIBPNG_LIBS="$abi_libpng_libs"
            LIBPNG_CFLAGS="-I$libpng_prefix/include"
            abi_libpng_message="libpng in $abi_libpng_libs"
	fi
    else
       AC_CHECK_HEADER(png.h,abi_found_libpngincs="yes")
       if test "$abi_found_libpngincs" = "yes"; then
           LIBPNG_LIBS="$abi_libpng_libs"
           LIBPNG_CFLAGS=""
           abi_libpng_message="libpng in $abi_libpng_libs"
       fi
    fi   
fi

# otherwise, use the sources given as an argument.  
# [ this means the peer dir for abi ]
if test "$abi_found_libpng" = "no"; then
    if test "x$1" != "x" && test -d "$1"; then
	abspath=`cd $1; pwd`
	LIBPNG_LIBS="${abspath}/libpng.a"
	LIBPNG_CFLAGS="-I${abspath}/"
	AC_MSG_RESULT(using supplied png library)	
	AC_DEFINE(HAVE_LIBPNG, 1, [ Define if you have libpng ])
	abi_libpng_message="supplied libpng in ${abspath}"
	LIBPNG_PEERDIR=${abspath}
        PEERDIRS="${PEERDIRS} ${LIBPNG_PEERDIR}"
	PEERS="${PEERS} `basename ${abspath}`"
    else
	AC_MSG_ERROR([ libpng was not found ])
    fi

fi

fi

AM_CONDITIONAL(LOCAL_LIBPNG, test "$local_libpng" = "true")
AC_SUBST(LIBPNG_CFLAGS)
AC_SUBST(LIBPNG_LIBS)
AC_SUBST(LIBPNG_PEERDIR)

])