--- /dev/null
+#!/usr/bin/env zsh
+# Copyright (C) 2022-2023 Sergey Matveev <stargrave@stargrave.org>
+
+VERSION=0.7.0
+
+set -e
+
+pagesize=${PAGESIZE:-100}
+ordering=${ORDERING:-Om}
+style=$STYLE
+
+exifTagsOmit=(
+ ExifToolVersion
+ Directory
+ FileAccessDate
+ FileAttributes
+ FileInodeChangeDate
+ FilePermissions
+)
+
+[[ -z $style ]] || style="<link rel=\"stylesheet\" type=\"text/css\" href=\"$style\">"
+
+mkdir -p alt .info preview
+setopt EXTENDED_GLOB
+
+imgs=()
+for img (*.jxl(N)) { [[ -r .info/$img.img ]] || imgs=($imgs $img) }
+[[ ${#imgs} == 0 ]] || {
+ echo Infos... >&2
+ parallel "jxlinfo {} > .info/{}.img" ::: $imgs
+}
+
+imgs=()
+src=(*.jxl)
+for img ($src) { [[ -r .info/$img.exif ]] || imgs=($imgs $img) }
+src=()
+[[ ${#imgs} == 0 ]] || {
+ echo Exif info... >&2
+ parallel "exiftool -escapeHTML -htmlFormat -groupHeadings --${=${(j/ --/)exifTagsOmit}} {} > .info/{}.exif" ::: $imgs
+}
+
+imgs=((*.jxl)($ordering))
+pages=$(( ${#imgs} / $pagesize ))
+[[ $(( $pages * $pagesize )) -lt ${#imgs} ]] && pages=$(( $pages + 1 ))
+
+local tmp=`mktemp`
+trap "rm -f $tmp" HUP PIPE INT QUIT TERM EXIT
+
+pams=()
+djxl2pam="( djxl --quiet {} ppm:- || djxl --quiet {} pgm:- )"
+if [[ -n "$NOALT" ]] ; then
+ for img ($imgs) {
+ [[ -r preview/$img.webp ]] || pams=($pams $img)
+ }
+else
+ jpgs=()
+ pngs=()
+ for img ($imgs) {
+ [[ -r .info/$img.img ]]
+ [[ -r alt/$img.jpg ]] || [[ -r alt/$img.png ]] && : || {
+ grep -q "JPEG bitstream reconstruction" .info/$img.img &&
+ jpgs=($jpgs $img) || pngs=($pngs $img)
+ }
+ [[ -r preview/$img.webp ]] || pams=($pams $img)
+ }
+
+ [[ ${#jpgs} == 0 ]] || {
+ echo JPEG reconstruction... >&2
+ parallel "djxl --quiet {} alt/{}.jpg && touch -r {} alt/{}.jpg" ::: $jpgs
+ }
+ jpgs=()
+
+ [[ ${#pngs} == 0 ]] || {
+ echo PNG generation... >&2
+ parallel "$djxl2pam | pamtopng > {}.png" ::: $pngs
+ parallel "pngcrush -warn -rem alla -rem allb -z 2 {}.png alt/{}.png && rm {}.png" ::: $pngs
+ parallel "advpng --quiet --recompress -4 alt/{}.png && touch -r {} alt/{}.png" ::: $pngs
+ }
+ pngs=()
+fi
+
+mkpreview="pnmscale -w 100"
+mkpreview="$mkpreview | cwebp -quiet -pass 10 -alpha_filter best -m 6 -o preview/{}.webp -- -"
+mkpreview="$mkpreview && touch -r {} preview/{}.webp"
+[[ ${#pams} == 0 ]] || {
+ echo Generating previews... >&2
+ parallel "$djxl2pam | $mkpreview" ::: $pams
+}
+pams=()
+
+for (( i=1 ; i <= ${#imgs} ; i++ )) {
+ local img=${imgs[$i]}
+ echo $i $img
+ local dst=$i.img.html
+ local p=$(( ( $i / $pagesize ) + 1 ))
+ cat > $tmp <<EOF
+<!DOCTYPE html>
+<html>
+ <head>
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+ <meta name="generator" content="galgen $VERSION">
+ ${style}
+ <title>Image ${i}/${#imgs}: $img</title>
+ <link href="1.page.html" rel="start" title="home">
+ <link href="${p}.page.html" rel="up" title="page">
+EOF
+ [[ $i -eq 1 ]] ||
+ echo "<link href=\"$(( $i - 1 )).img.html\" rel=\"prev\" title=\"previous\">" >> $tmp
+ [[ $i -eq ${#imgs} ]] ||
+ echo "<link href=\"$(( $i + 1 )).img.html\" rel=\"next\" title=\"next\">" >> $tmp
+ cat >> $tmp <<EOF
+ </head>
+<body>
+EOF
+ [[ $i -eq 1 ]] ||
+ echo "<a href=\"$(( $i - 1 )).img.html\"><<<</a>" >> $tmp
+ echo "<a href=\"${p}.page.html\">^^^</a>" >> $tmp
+ [[ $i -eq ${#imgs} ]] ||
+ echo "<a href=\"$(( $i + 1 )).img.html\">>>></a>" >> $tmp
+ echo "<hr/><img alt=\"$img\" src=\"$img\"/>" >> $tmp
+ [[ -r ${img}.txt ]] && {
+ echo "<hr/><pre>" >> $tmp
+ cat ${img}.txt >> $tmp
+ echo "</pre>" >> $tmp
+ }
+ [[ -r ${img}.html ]] && cat ${img}.html >> $tmp
+ echo "<hr/>" >> $tmp
+ [[ -r .info/$img.img ]]
+ echo "<pre>" >> $tmp
+ cat .info/$img.img >> $tmp
+ echo "</pre>" >> $tmp
+ [[ -n "$NOALT" ]] || {
+ if [[ $img:e = jxl ]] ; then
+ echo "Alternative formats:" >> $tmp
+ [[ -r alt/$img.jpg ]] && {
+ echo "<a href=\"alt/$img.jpg\">JPEG</a>" >> $tmp
+ } || {
+ echo "<a href=\"$img.png\">PNG</a>" >> $tmp
+ }
+ fi
+ echo "<hr/>" >> $tmp
+ }
+ [[ -r .info/$img.exif ]]
+ cat .info/$img.exif >> $tmp
+ echo "</body></html>" >> $tmp
+ cmp -s $tmp $dst || {
+ cat $tmp > $dst
+ touch -r $img $dst
+ }
+}
+
+for (( p=1 ; p <= $pages ; p++ )) {
+ local dst=$p.page.html
+ cat > $tmp <<EOF
+<!DOCTYPE html>
+<html>
+ <head>
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+ <meta name="generator" content="galgen $VERSION">
+ ${style}
+ <title>Page ${p}/$pages</title>
+ <link href="1.page.html" rel="start" title="home">
+EOF
+ [[ $p -eq 1 ]] ||
+ echo "<link href=\"$(( $p - 1 )).page.html\" rel=\"prev\" title=\"previous\">" >> $tmp
+ [[ $p -eq $pages ]] ||
+ echo "<link href=\"$(( $p + 1 )).page.html\" rel=\"next\" title=\"next\">" >> $tmp
+ cat >> $tmp <<EOF
+ </head>
+<body>
+EOF
+ [[ $p -eq 1 ]] && {
+ [[ -r .txt ]] && {
+ echo "<pre>" >> $tmp
+ cat .txt >> $tmp
+ echo "</pre>" >> $tmp
+ }
+ [[ -r .html ]] && cat .html >> $tmp
+ }
+ [[ $p -eq 1 ]] ||
+ echo "<a href=\"$(( $p - 1 )).page.html\"><<<</a>" >> $tmp
+ [[ $p -eq $pages ]] ||
+ echo "<a href=\"$(( $p + 1 )).page.html\">>>></a>" >> $tmp
+ echo "| <a href=\"1.page.html\">home</a>" >> $tmp
+ echo "| <a href=\"${pages}.page.html\">end</a>" >> $tmp
+ echo "<hr/>" >> $tmp
+ for (( i=1 ; i <= $pagesize ; i++ )) {
+ img=$(( ( $p - 1 ) * $pagesize + $i ))
+ [[ $img -le ${#imgs} ]] || break
+ echo "<a href=\"${img}.img.html\">" >> $tmp
+ alt="preview ${img}"
+ title=""
+ [[ -r ${imgs[$img]}.txt ]] && {
+ alt=`cat ${imgs[$img]}.txt`
+ title="title=\"$alt\""
+ }
+ echo "<img alt=\"$alt\" $title src=\"preview/${imgs[$img]}.webp\"/></a>" >> $tmp
+ }
+ echo "</body></html>" >> $tmp
+ cmp -s $tmp $dst || {
+ cat $tmp > $dst
+ echo page $p
+ }
+}