/useful/trunk-1

#!/usr/bin/env bash

####

# FILE NAME process_text_to_image.sh

#

# Authors:

#    Gustav Hartvigsson 2024

#    Distributed under the Cool Licence 1.1

#

# Changes

#

# 2018-09-03:

#   * added --no-header for when you want to use your own pandoc header

#

# 2018-09-22

#   * Fixed --no-header...

#     Seemed to have forgotten the "$" infront of the variable.

#

# 2021-01-13

#   * fixed up the if statments.

#

# 2024-07-10

#   * Added sanity check

#   * General logic fixes.

#   * Added --author argument

#   * Fixed help message formating

####

__DPI=300

__IN_FILE=

__OUT_FILE=big_image

__PERSERVE_TMP=false

__INVERT_COLOURS=false

__NO_PANDOC_HEADER=false

__CWD=$PWD

__PANDOC_HEADER="

geometry: margin=0.5cm

papersize: a5

mainfont: DejaVu Serif

fontsize: 12pt

"

__TITLE=""

__AUTHOR=""

__SANITY=true

__SCRIPT_ROOT=$(dirname $(readlink -f $0))

source $__SCRIPT_ROOT/useful.inc.sh

function __usage () {

  echo "process_text_to_image.sh - Takes one text file and convernts it to a single"

  echo "image using pandoc, xelatex, imagemagick, pdftoppm, pdfcrop"

  echo ""

  echo "!IMPORTANT! The folder \"./tmp/\" in the current working directory will be"

  echo "            used as a temporary storage, and may be deleted, along with it's"

  echo "            contents!"

  echo ""

  echo "---------------------"

  echo ""

  echo "-h             --help"

  echo "	Print this help message"

  echo ""

  echo "-i <file>      --input <file>"

  echo "	The file to use to convert to an image. "

  echo ""

  echo "-o <file>      --output <file>"

  echo "	The image to output to. (Default=big_image.png)"

  echo ""

  echo "-d <integer>   --dpi <integer>"

  echo "	Set the dpi of the intermediate image relative to an a5 paper."

  echo "	(Default=300)"

  echo ""

  echo "-p             --perserve"

  echo "	Do not delete the TMP folder."

  echo ""

  echo "--invert"

  echo "	Invert the colours of the final image."

  echo ""

  echo "-t \"name\"      --title \"name\""

  echo "	Set the title on the the title page."

  echo ""

  echo "-a \"name\"      --author \"name\""

  echo "        Set an author to the title page."

  echo ""

  echo "--no-header"

  echo "	Do not insert the pandoc header. (Default:"

  echo "$__PANDOC_HEADER"

  echo ")"

  echo ""

  echo "---------------------"

  echo ""

  echo "If you are getting an error from convert that the height or width exeeds"

  echo "some value, you may want to check the ImageMagick policy.xml file."

  echo ""

  echo "The path to ImageMagick policy file is:"

  convert -list policy | grep .xml 

  echo ""

  echo "---------------------"

}

function __sanity_check () {

  # Check that we have the tools needed.

  __find_tool pandoc

  __find_tool xelatex

  __find_tool convert

  __find_tool pdftoppm

  __find_tool pdfcrop

  if [[ $__SANITY == false ]]; then

    echo ""

    echo "Please install the missing tools."

    echo ""

    exit 1

  fi

}

function __main () {

  # FIXME: Split the functionality out of the main function.

  # FIXME: Use mkdtemp instead of the folder we are in.

  __parse_args "${@}"

  __sanity_check

  echo "__IN_FILE\: $__IN_FILE"

  echo "__OUT_FILE\: $__OUT_FILE"

  echo "CWD\: $__CWD"

  echo "__DPI: $__DPI"

  if [[ ! -e "$__CWD/$__IN_FILE" ]] || [[ -z $__IN_FILE  ]]

  then

    echo "The provided <infile> does not exit."

    echo ""

    exit 1

  fi

  # first we create a temp folder.

  mkdir -p "$__CWD/tmp"

  #next we want to copy our file into it.

  cp "$__CWD/$__IN_FILE" "$__CWD/tmp/text.txt"

  cd "$__CWD/tmp"

  # Now we can start the work for this.

  if [[ $__NO_PANDOC_HEADER == false ]]

  then

    # FIXME: This is cursed.

    # We add a special header to the file to make it pandoc know what to do.

    #

    # The header is built from the bottom up. The input text at the bottom, and

    # the rest of the "elements" added above.

    printf '%s\n' "---" "$(cat "$__CWD/tmp/text.txt")" > "$__CWD/tmp/text.txt"

    if [[ ! -z $__TITLE ]]; then

      printf '%s\n' "title: ${__TITLE}" "$(cat "$__CWD/tmp/text.txt")" > "$__CWD/tmp/text.txt"

    fi

    if [[ ! -z $__AUTHOR ]]; then

      printf '%s\n' "author: ${__AUTHOR}" "$(cat "$__CWD/tmp/text.txt")" > "$__CWD/tmp/text.txt"

    fi

    printf '%s' "$__PANDOC_HEADER" "$(cat "$__CWD/tmp/text.txt")" > "$__CWD/tmp/text.txt"

    printf '%s' "---" "$(cat "$__CWD/tmp/text.txt")" > "$__CWD/tmp/text.txt"

  fi

  # Now we use pandoc to do to convert it to a PDF.

  echo "Generating PDF"

  pandoc --pdf-engine=xelatex "$__CWD/tmp/text.txt" -o "$__CWD/tmp/text.pdf"

  echo "Cropping PDF"

  pdfcrop --margins '10 5 10 5' "$__CWD/tmp/text.pdf" "$__CWD/tmp/text-croped.pdf"

  # Convert it to images

  echo "Converting to images"

  pdftoppm "$__CWD/tmp/text-croped.pdf" "$__CWD/tmp/page" -png -rx $__DPI -ry $__DPI -gray

  # convert make the colour space greyscale and the append to each other

  convert -append -colorspace gray +matte -depth 8 "$__CWD/tmp/page-*.png" "$__CWD/tmp/big-page.png"

  FINAL_IMAGE=""

  # If we invert the final image this is where we do it.

  if [[ $__INVERT_COLOURS == true ]]

  then

    echo "Inverting colours"

    convert "$__CWD/tmp/big-page.png" -channel RGB -negate "$__CWD/tmp/big-page-inverted.png"

    FINAL_IMAGE="$__CWD/tmp/big-page-inverted.png"

  else

    FINAL_IMAGE="$__CWD/tmp/big-page.png"

  fi

  echo "Copying final image to $__CWD/$__OUT_FILE.png"

  cp "$FINAL_IMAGE" "$__CWD/$__OUT_FILE.png"

  ####

  # Cleanup of eveything.

  ####

  if [[ $__PERSERVE_TMP == true ]]

  then

    echo "Note: Not cleaning up!"

  else

    rm -r "$__CWD/tmp"

  fi

  echo "Done."

  echo ""

}

function __parse_args () {

  if [[ -z "$1" ]]

  then

    echo "Try --help or -h."

    exit 1

  fi

  while [[ $# -gt 0 ]]

  do

    case $1 in

      -i|--input)

        __IN_FILE="$2"

        shift

        shift

      ;;

      -o|--output)

        __OUT_FILE="$2"

        shift

        shift

      ;;

      -t|--title)

        __TITLE="$2"

        shift

        shift

      ;;

      -a|--author)

        __AUTHOR="$2"

        shift

        shift

      ;;

      -d|--dpi)

        __DPI="$2"

        shift

        shift

      ;;

      -p|--perserve)

        __PERSERVE_TMP=true

        shift

      ;;

      --invert)

        __INVERT_COLOURS=true

        shift

      ;;

      --no-header)

        __NO_PANDOC_HEADER=true

        shift

      ;;

      -h|--help)

         __usage

         exit

         shift

      ;;

      *)

        echo "Unkown argument \"${1}\"."

        exit 1

        shift

      ;;

      --)

        shift

        break

      ;;

    esac

  done

}

__main "${@}"