#!/usr/bin/env bash

# Compress pdf files using ghostscript.
#
# Defaults to 72 dpi.
#
# Usage:
#   pdfoptim SRC [TARGET] [DPI]
#
# Requires: ghostscript (gs)

optimize() {
    # Adapted from Alfred Klomp's shrinkpdf script
    # <http://alfredklomp.com/programming/shrinkpdf/>
    gs -q -dNOPAUSE -dBATCH -dSAFER \
        -sDEVICE=pdfwrite \
        -dPDFSETTINGS=/screen \
        -dCompatibilityLevel=1.3 \
        -dEmbedAllFonts=true \
        -dSubsetFonts=true \
        -dAutoRotatePages=/None \
        -dMonoImageResolution=$3 \
        -dMonoImageDownsampleType=/Bicubic \
        -dGrayImageResolution=$3 \
        -dGrayImageDownsampleType=/Bicubic \
        -dColorImageResolution=$3 \
        -dColorImageDownsampleType=/Bicubic \
        -sOutputFile="$2" \
	    "$1"
}

SRC="$1"
DEST="${2:--}"
DPI="${3:-72}"

optimize "$SRC" "$DEST" "$DPI" || exit $?