#!/bin/bash
#
# render_doIdentityImageGrub.sh -- This function provides
# post-rendering action used to produce GRUB images.
#
# Copyright (C) 2009-2010 Alain Reguera Delgado
# 
# 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
# USA.
# 
# ----------------------------------------------------------------------
# $Id: render_doIdentityImageGrub.sh 71 2010-09-18 05:41:11Z al $
# ----------------------------------------------------------------------

function render_doIdentityImageGrub {

    local FILE=$1

    # Define Motif's palette location. We do this relatively.
    local PALETTES=/home/centos/artwork/trunk/Identity/Themes/Motifs/$(cli_getThemeName)/Colors

    # Define the Netpbm color palettes used when reducing colors.
    # These palettes should be 14 colors based. For more information
    # on this see the GRUB's documentation.
    local PALETTE_PPM=$PALETTES/grub.ppm

    # Check GRUB's palettes existence:  If there is no palette assume
    # that this is the first time you are rendering GRUB images. If
    # that is the case the script will provide you with the PNG format
    # which should be used as base to produce (using GIMP) the .gpl
    # palette.  The .gpl palette information is used to produced
    # (using GIMP) the colormap (.ppm) which is used to automate the
    # GRUB's 14 colors image (splash.png) rendering.  If there is no
    # palette available, do not apply color reduction, show a message,
    # and continue.
    cli_checkFiles $PALETTE_PPM

    # Create Netpbm superformat (PNM). PNM file is created from the
    # PNG image rendered previously. PNM is a common point for image
    # manipulation using Netpbm tools.
    cli_printMessage "$FILE.pnm" "AsSavedAsLine"
    pngtopnm -verbose \
        < $FILE.png \
        2>$FILE.log \
        > $FILE.pnm

    # Reduce colors. Here we use the Netpbm color $PALETTE_PPM to
    # enforce the color position in the image index and the
    # Floyd-Steinberg dithering in order to improve color reduction.
    cli_printMessage "$FILE-14c.ppm" "AsSavedAsLine"
    pnmremap -verbose -floyd -mapfile=$PALETTE_PPM \
        < $FILE.pnm \
        2>>$FILE.log \
        > $FILE-14c.ppm

    # Create the XPM.GZ file. This is the file we put at
    # /boot/grub/splash.xpm.gz.
    cli_printMessage "$FILE.xpm.gz" "AsSavedAsLine"
    ppmtoxpm \
        < $FILE-14c.ppm \
        2>>$FILE.log \
        > $FILE.xpm \
        && gzip --force $FILE.xpm
   
}