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74 lines
1.5 KiB
Bash
74 lines
1.5 KiB
Bash
#!/bin/bash
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set -euo pipefail
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help_message="$(cat <<END
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usage: $(basename "$0") [OPTIONS...] INPUT_PDF OUTPUT_PDF
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Converts a PDF file to a series of JPEG images to reduce the quality
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and then merges them back in a single pdf.
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Options:
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-q, --quality Set the JPEG quality (default: 75)
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-h, --help Display this help message
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END
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)"
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function show_usage() {
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echo "$help_message"
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exit 1
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}
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quality=75
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while [[ $# -gt 0 ]]
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do
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key="$1"
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case $key in
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-q|--quality)
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quality="$2"
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shift # past argument
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shift # past value
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;;
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-h|--help)
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show_usage
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;;
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-*)
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echo "Unknown option: $key"
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show_usage
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;;
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*)
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break
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;;
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esac
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done
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if [ -z "$1" ] || [ -z "$2" ]; then
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show_usage
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fi
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input_file="$1"
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output_file="$2"
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temp_pages_dir="$(mktemp -d)"
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function logf {
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printf "$@"
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}
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logf "Rendering each page to a jpeg image (quality = $quality)\n"
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pdftoppm -r 300 -jpeg -jpegopt "quality=$quality,optimize=y" -progress $input_file "$temp_pages_dir/page"
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for f in "$temp_pages_dir"/page-*.jpg; do
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logf "Wrapping $f into ${f/.jpg/.pdf}\n"
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gs -dNOSAFER -sDEVICE=pdfwrite -o "${f/.jpg/.pdf}" $(find -iname viewjpeg.ps /usr/share | head -1) -c "($f)" viewJPEG
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done
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logf "Merging compressed pages to a single PDF\n"
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pdfunite "$temp_pages_dir"/page-*.pdf $output_file
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rm -r "$temp_pages_dir"
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logf "Done\n"
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