73 lines
1.9 KiB
Bash
73 lines
1.9 KiB
Bash
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#!/bin/sh
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# PNGizer: convert any file into PNG image and back
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# Depends on mktemp, tar, ImageMagick and pngcrush
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# Created by Luxferre in 2026, released into public domain
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# Convert any raw data file to PNG
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# Usage: pngize_raw $infile $pngfile
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pngize_raw() {
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temp_ppm="$(mktemp)"
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# get raw input size
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fsize=$(wc -c < "$1")
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# calculate image side length to fit everything
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sidelen=$(echo "scale=0;1 + sqrt($fsize / 3 + 1)" | bc -l)
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# how many trailing zero bytes we need
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remlen=$((sidelen * sidelen * 3 - fsize))
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# shape the PPM file:
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# 1. header (PPM binary)
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printf 'P6\n%s %s\n255\n' $sidelen $sidelen > $temp_ppm
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# 2. body (raw file data)
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cat "$1" >> $temp_ppm
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# 3. trailing zero bytes
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for i in $(seq 1 $remlen); do printf '\x00' >> $temp_ppm; done
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# convert PPM to PNG and remove the temporary PPM
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magick ppm:$temp_ppm png:$ofile
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rm -f $temp_ppm
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}
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# extract any raw data file from PNG
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# Usage: unpngize_raw $pngfile $outfile
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unpngize_raw() {
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temp_ppm="$(mktemp)"
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# convert PNG to PPM (should be P6)
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magick png:$1 ppm:$temp_ppm
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# extract the raw body
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tail -n +4 $temp_ppm > $2
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# remove the temporary PPM
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rm -f $temp_ppm
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}
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# Convert any file or directory to PNG
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pngize() {
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ofile="$2"
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[ -z "$2" ] && ofile="$1.png"
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temp_arch="$(mktemp)"
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# containerize the input
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tar cf $temp_arch "$1"
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# run the conversion
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pngize_raw $temp_arch $ofile
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rm -f $temp_arch
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# apply compression
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pngcrush -ow $ofile
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}
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# Extract the file or directory from PNG
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unpngize() {
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temp_arch="$(mktemp)"
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unpngize_raw "$1" $temp_arch
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tar xf $temp_arch
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rm -f $temp_arch
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}
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# entry point
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[ -z "$2" ] && echo 'No input file specified! Exiting...' && exit 1
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if [ "$1" = "e" ]; then
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[ -z "$3" ] && echo "No output file specified! Using $2.png as output file"
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pngize "$2" "$3"
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elif [ "$1" = "d" ]; then
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unpngize "$2"
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else
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echo 'Invalid mode! Use e for encoding or d for decoding'
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fi
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