#!/bin/bash

#

# render_svg_convertPngToSyslinux.sh -- This function provides post-rendition

# action used to produce LSS16 images, the images used by isolinux.

#

# This function uses three different formats to handle the same color

# information. Initially, the color information is defined with GIMP

# (The GNU Image Manipulation Program) as a palette of color. This

# palette of colors contains 16 colors only and is saved in a file

# named `syslinux.gpl.

#

# The `syslinux.gpl' file is used to build two other files: the

# `syslinux.ppm' file and the `syslinux.hex' file. The `syslinux.ppm'

# file is used to reduce a full color PNG image to the amount of

# colors it specifies (i.e., 16 colors). Later, with the 16 color

# image already created, the `syslinux.hex' file is used to build the

# LSS16 image.

#

# In order to produce images in LSS16 format correctly, it is needed

# that both the `syslinux.ppm' and `syslinux.hex' files contain the

# same color information. This is, both `syslinux.ppm' and

# `syslinux.hex' shoud represent the same color values and the same

# color index.

#

# This function save you the work of preparing both `syslinux.ppm' and

# `syslinux.hex'. Instead, you only need to prepare the `syslinux.gpl'

# file with the color information you want to produce images.

#

# In order for this function to work, the `syslinux.gpl' file should

# have a format similar to the following:

#

# GIMP Palette

# Name: TreeFlower-4-Syslinux

# Columns: 16

# #

# 10  22  40     0a1628

# 9  28  52     091c34

# 16  34  63     10223f

# 20  37  67     142543

# 15  39  74     0f274a

# 12  45  85     0c2d55

# 20  43  78     142b4e

# 255 255 255     ffffff

# 21  51  95     15335f

# 41  52  70     293446

# 32  76 141     204c8d

# 77  90 107     4d5a6b

# 143 154 167     8f9aa7

# 128 179 255     80b3ff

# 194 200 202     c2c8ca

# 231 241 255     e7f1ff

#

# 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_svg_convertPngToSyslinux {

    # Define number of colors the images will be produced on.

    local COLOR_NUMBER='16'

    # 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 already used in this script. For example

    # -verbose and -mapfile options.

    for OPTION in $OPTIONS;do

        # Remove anything after equal sign inside option.

        OPTION=$(echo $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 default file name prefix for 16 colors images.

    local PREFIX="-${COLOR_NUMBER}c"

    # Re-define 16 colors images default file name prefix using

    # options as reference. This is useful to differenciate final

    # files produced using Floyd-Steinberg dithering and final 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 $ACTIONVAL --theme)/Palettes

    # Define absolute path to GPL palette. The GPL palette defines the

    # color information used to build syslinux images.  This palette

    # should be set to 16 colors and, as specified in isolinux

    # documentation, the background color should be indexed on

    # position 0 and the forground in position 7 (see

    # /usr/share/doc/syslinux-X.XX/isolinux.doc, for more

    # information.)

    local PALETTE_GPL=${PALETTES}/syslinux.gpl

    # Verify GPL palette existence.

    cli_checkFiles $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=$(cli_getTemporalFile "syslinux.ppm")

    # 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=$(cli_getTemporalFile "syslinux.hex")

    # 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_svg_convertGplToPpm "$PALETTE_GPL" "$PALETTE_PPM" "$COLOR_NUMBER"

    # Create HEX palette using GPL palette.

    render_svg_convertGplToHex "$PALETTE_GPL" "$PALETTE_HEX" "$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}.pnm" --as-savedas-line

    pnmremap -verbose -mapfile=$PALETTE_PPM $OPTIONS \

        < ${FILE}.pnm 2>> ${FILE}.log > ${FILE}${PREFIX}.pnm

    # Create LSS16 image. 

    cli_printMessage "${FILE}${PREFIX}.lss" --as-savedas-line

    ppmtolss16 $(cat $PALETTE_HEX) \

        < ${FILE}${PREFIX}.pnm 2>>${FILE}.log > ${FILE}${PREFIX}.lss

    # Remove HEX palette. It is no longer needed.

    if [[ -f ${PALETTE_HEX} ]];then

        rm $PALETTE_HEX

    fi

    # Create the 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.

    cli_printMessage "${FILE}${PREFIX}.ppm" --as-savedas-line

    lss16toppm -map \

        < ${FILE}${PREFIX}.lss 2>>${FILE}.log > ${FILE}${PREFIX}.ppm

    # Create the 16 colors PNG image.

    cli_printMessage "${FILE}${PREFIX}.png" --as-savedas-line

    pnmtopng -verbose -palette=$PALETTE_PPM \

        < ${FILE}${PREFIX}.pnm 2>>${FILE}.log > ${FILE}${PREFIX}.png

    # Remove PPM palette. It is no longer needed.

    if [[ -f ${PALETTE_PPM} ]];then

        rm $PALETTE_PPM

    fi

}