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97 lines
2.1 KiB
Bash
97 lines
2.1 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 "$0") [OPTIONS...] INPUT_PDF OUTPUT_PDF
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Converts a PDF file to a series of JPEG images using convert to reduce the quality
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and then merges back the result in a single pdf
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Options:
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-q, --quality Set the JPEG quality (default: 75)
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-v, --verbose Enable verbose output, also shows an estimate of remaining time
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-h, --help Display this help message
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END
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)"
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function show_usage() {
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echo "$help_message"
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exit 1
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}
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quality=75
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verbose=false
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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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-v|--verbose)
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verbose=true
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shift # past argument
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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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if [ "$verbose" = true ]; then
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printf "$@"
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fi
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}
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logf "Converting \"$input_file\" to \"$output_file\"\n"
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page_count=$(pdfinfo "$input_file" | grep Pages | awk '{print $2}')
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logf "Processing $page_count pages\n"
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start=$(date +%s.%N)
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for i in $(seq 0 $((page_count-1))); do
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iter_start=$(date +%s.%N)
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convert -density 300 -quality "$quality" "${input_file}[$i]" "$temp_pages_dir/$i.jpg"
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# Compute estimated remaining time
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end=$(date +%s.%N)
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elapsed=$(echo "$end - $start" | bc)
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iter_elapsed=$(echo "$end - $iter_start" | bc)
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remaining=$(echo "($elapsed / ($i + 1)) * ($page_count - $i)" | bc)
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remaining_fmt=$(printf "%02d:%02d:%02d" $((remaining/3600)) $((remaining/60)) $((remaining%60)))
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logf "Compressed page $((i+1)) in $(printf '%.2f' "$iter_elapsed")s (estimated remaining time $remaining_fmt)\n"
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done
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logf "Merging compressed pages to a single PDF\n"
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convert "$temp_pages_dir"/*.jpg "$output_file"
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rm -r "$temp_pages_dir"
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logf "Done\n"
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