#!/bin/bash

######################################################################

#

#   palette.sh -- This function standardizes the way palette of colors

#   are applied to image files in order to produce images with

#   specific number of colors.

#

#   Written by:

#   * Alain Reguera Delgado <al@centos.org.cu>, 2009-2013

#

# Copyright (C) 2009-2013 The CentOS Artwork SIG

#

# 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.

#

######################################################################

function palette {

    local FILENAME=$(tcar_getTemporalFile "$(echo ${SOURCES[0]} \

        | sed -r 's/\.[[:alpha:]]+$//')")

    local LOGS=${RENDER_TARGET}.log

    # Define absolute path to GPL palette. This file is the reference

    # taken to set the max number of colors the final image will be

    # produced for.

    local PALETTE_GPL=$(tcar_getConfigValue ${CONFIGURATION} ${SECTION} 'palette-gpl')

    tcar_checkFiles -ef ${PALETTE_GPL}

    local PALETTE_GPL_COLORS=$(palette_getColors "${PALETTE_GPL}")

    # 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=$(tcar_getTemporalFile 'palette.ppm')

    # Verify format of colors returned in the list.

    palette_checkColorFormats "${PALETTE_GPL_COLORS}"

    # 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.

    pngtopnm -verbose \

        < ${SOURCES[0]} 2>${LOGS} > ${FILENAME}.pnm

    # Create PPM palette using GPL palette.

    palette_convertGplToPpm

    # 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.

    pnmremap -verbose -mapfile=${PALETTE_PPM} -floyd \

        < ${FILENAME}.pnm 2>>${LOGS} > ${FILENAME}.ppm

    # Print action message.

    tcar_printMessage "${RENDER_TARGET}" --as-creating-line

    if [[ ${RENDER_TARGET} =~ '\.lss$' ]];then

        # Define the HEX palette. The HEX palette is built from source

        # palette (PALETTE_GPL) and provides the color information in

        # the format understood by `ppmtolss16', the program used to

        # produce images in LSS16 format.  The HEX palette stores just

        # one line with the color information as described in isolinux

        # documentation (i.e #RRGGBB=0 #RRGGBB=1 ... [all values in

        # the same line])

        local PALETTE_HEX=$(tcar_getTemporalFile "palette.hex")

        # Create HEX palette using GPL palette.

        palette_convertGplToHex

        # Create LSS16 image. 

        ppmtolss16 $(cat ${PALETTE_HEX}) \

            < ${FILENAME}.ppm 2>>${LOGS} > ${RENDER_TARGET}

        # Create PPM image indexed to 16 colors. Also the colormap

        # used in the LSS16 image is saved on ${FILE}.log; this is

        # useful to verify the correct order of colors in the image

        # index.

        lss16toppm -map \

            < ${RENDER_TARGET} 2>>${LOGS} > ${RENDER_TARGET}.ppm

    else

        # Create final file.

        /usr/bin/convert ${FILENAME}.ppm ${RENDER_TARGET}

    fi

}