#!/bin/bash
#
# render_doGrub.sh -- This function provides post-rendition
# action used to produce GRUB images.
#
# Copyright (C) 2009, 2010, 2011 The CentOS Project
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or (at
# your option) any later version.
#
# This program 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
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
# ----------------------------------------------------------------------
# $Id$
# ----------------------------------------------------------------------

function render_doGrub {

    # Define number of colors the images will be produced on.
    local COLOR_NUMBER='14'

    # Define options using those passed to actions from pre-rendition
    # configuration script. These options are applied to pnmremap when
    # doing color reduction, so any option available for pnmremap
    # command can be passed to renderSyslinux functionality.
    local OPTIONS=$(render_getConfigOption "$ACTION" '2-')

    # Check options passed to action. This is required in order to
    # aviod using options used already in this script. For example
    # -verbose and -mapfile options.
    for OPTION in $OPTIONS;do
        # Remove anything after equal sign inside option.
        OPTION=$(echo -n $OPTION | cut -d'=' -f1)
        if [[ "$OPTION" =~ "-(mapfile|verbose)" ]];then
            cli_printMessage "`eval_gettext "The \\\"\\\$OPTION\\\" option is already used."`" --as-error-line
        fi
    done

    # Define file name prefix.
    local PREFIX="-${COLOR_NUMBER}c"

    # Redefine file name prefix using options as reference. This is
    # useful to differenciate final files produced using
    # Floyd-Steinberg dithering and files which are not.
    if [[ "$OPTIONS" =~ '-floyd' ]];then
        PREFIX="${PREFIX}-floyd"
    fi

    # Define theme-specific palettes directory. 
    local PALETTES=$(cli_getRepoTLDir)/Identity/Images/Themes/$(cli_getPathComponent '--theme')/Palettes

    # Define absolute path to GPL palette.  This palettes should have
    # 14 colors only. For more information on this see the GRUB's
    # documentation.
    local PALETTE_GPL=${PALETTES}/grub.gpl

    # Verify GPL palette existence.
    cli_checkFiles $PALETTE_GPL 'f'

    # Define absolute path to PPM palette. The PPM palette is built
    # from source palette (PALETTE_GPL) and provides the color
    # information understood by `ppmremap', the program used to
    # produce images in a specific amount of colors.
    local PALETTE_PPM=$(cli_getTemporalFile "grub.ppm")

    # Create image in Netpbm superformat (PNM). The PNM image file is
    # created from the PNG image rendered previously as centos-art
    # base-rendition output. The PNM image is an intermediate format
    # used to manipulate images through Netpbm tools.
    cli_printMessage "${FILE}.pnm" --as-savedas-line
    pngtopnm -verbose \
        < ${FILE}.png 2>${FILE}.log > ${FILE}.pnm

    # Print the path to GPL palette.
    cli_printMessage "$PALETTE_GPL" --as-palette-line

    # Create PPM palette using GPL palette.
    render_convertGplToPpm "$PALETTE_GPL" "$PALETTE_PPM" "$COLOR_NUMBER"

    # Reduce colors as specified in PPM palette.  Here we use the PPM
    # palette to enforce the color position in the image index and the
    # Floyd-Steinberg dithering in order to improve color reduction.
    cli_printMessage "${FILE}${PREFIX}.ppm" --as-savedas-line
    pnmremap -verbose -mapfile=$PALETTE_PPM $OPTIONS \
        < ${FILE}.pnm 2>>${FILE}.log > ${FILE}${PREFIX}.ppm

    # Remove PPM palette. It is no longer needed.
    if [[ -f ${PALETTE_PPM} ]];then
        rm $PALETTE_PPM
    fi

    # Create the 14 colors xpm.gz file.
    cli_printMessage "${FILE}${PREFIX}.xpm.gz" --as-savedas-line
    ppmtoxpm \
        < ${FILE}${PREFIX}.ppm 2>>${FILE}.log > ${FILE}.xpm \
        && gzip --force ${FILE}.xpm \
        && mv ${FILE}.xpm.gz ${FILE}${PREFIX}.xpm.gz

}