plugins/preview-tui

   1 #!/usr/bin/env bash
   2
   3 # Description: Terminal based file previewer
   4 #
   5 # Note: This plugin needs a "NNN_FIFO" to work. See man.
   6 #
   7 # Dependencies:
   8 #   - Supports 6 independent methods to preview with:
   9 #       - tmux (>=3.0), or
  10 #       - kitty with allow_remote_control and listen_on set in kitty.conf, or
  11 #       - wezterm (https://wezfurlong.org/wezterm), or
  12 #       - QuickLook on WSL (https://github.com/QL-Win/QuickLook), or
  13 #       - Windows Terminal (https://github.com/Microsoft/Terminal | https://aka.ms/terminal) with WSL, or
  14 #       - $NNN_TERMINAL set to a terminal (it's xterm by default).
  15 #   - less or $NNN_PAGER
  16 #   - tree or exa/eza or (GNU) ls
  17 #   - mediainfo or file
  18 #   - mktemp
  19 #   - unzip
  20 #   - tar
  21 #   - man
  22 #   - optional: bsdtar or atool for additional archive preview
  23 #   - optional: bat for code syntax highlighting
  24 #   - optional: ueberzug, kitty terminal, wezterm terminal, img2sixel, viu, catimg or chafa for images
  25 #   - optional: convert(ImageMagick) for playing gif preview (mandatory for kitty image previews)
  26 #   - optional: mpv for gif and video
  27 #       Also requires a terminal supporting the sixel (https://www.arewesixelyet.com/)
  28 #       or kitty (https://sw.kovidgoyal.net/kitty/graphics-protocol) video_output backends.
  29 #       Requires tmux compiled with `./configure --enable-sixel` if used.
  30 #   - optional: ffmpegthumbnailer for video thumbnails (https://github.com/dirkvdb/ffmpegthumbnailer)
  31 #   - optional: ffmpeg for audio thumbnails
  32 #   - optional: libreoffce for opendocument/officedocument preview
  33 #   - optional: pdftoppm(poppler) for pdf thumbnails
  34 #   - optional: gnome-epub-thumbnailer for epub thumbnails (https://gitlab.gnome.org/GNOME/gnome-epub-thumbnailer)
  35 #   - optional: fontpreview for font preview (https://github.com/sdushantha/fontpreview)
  36 #   - optional: djvulibre for djvu
  37 #   - optional: glow or lowdown for markdown
  38 #   - optional: w3m or lynx or elinks for html
  39 #   - optional: set/export NNN_ICONLOOKUP as 1 to enable file icons in front of directory previews with .iconlookup
  40 #       Icons and colors are configurable in .iconlookup
  41 #   - optional: scope.sh file viewer from ranger.
  42 #       1. drop scope.sh executable in $PATH
  43 #       2. set/export $NNN_SCOPE as 1
  44 #   - optional: pistol file viewer (https://github.com/doronbehar/pistol).
  45 #       1. install pistol
  46 #       2. set/export $NNN_PISTOL as 1
  47 #
  48 # Usage:
  49 #   You need to set a NNN_FIFO path and a key for the plugin with NNN_PLUG,
  50 #   then start `nnn`:
  51 #
  52 #     $ nnn -a
  53 #
  54 #   or
  55 #
  56 #     $ NNN_FIFO=/tmp/nnn.fifo nnn
  57 #
  58 #   Then launch the `preview-tui` plugin in `nnn`.
  59 #
  60 #   If you provide the same NNN_FIFO to all nnn instances, there will be a
  61 #   single common preview window. If you provide different FIFO path (e.g.
  62 #   with -a), they will be independent.
  63 #
  64 #   The previews will be shown in a tmux split. If that isn't possible, it
  65 #   will try to use a kitty terminal split. And as a final fallback, a
  66 #   different terminal window will be used ($NNN_TERMINAL).
  67 #
  68 #   Kitty users need something similar to the following in their kitty.conf:
  69 #   - `allow_remote_control yes`
  70 #   - `listen_on unix:$TMPDIR/kitty`
  71 #   - `enabled_layouts splits` (optional)
  72 #   With ImageMagick installed, this terminal can use the icat kitten to display images.
  73 #   Refer to kitty documentation for further details.
  74 #
  75 #   Wezterm should work out of the box. If `NNN_PREVIEWIMGPROG` is not specified it will use
  76 #   built in iTerm2 image protocol.
  77 #
  78 #   Note that GNU ls is used for its `--group-directories-first` flag.
  79 #   On MacOS this may be installed with `brew install coreutils`, or the flag can be removed.
  80 #   iTerm2 users are recommended to use viu to view images without getting pixelated.
  81 #
  82 #   Windows Terminal users can set "Profile termination behavior" under "Profile > Advanced" settings
  83 #   to automatically close pane on quit when exit code is 0.
  84 #
  85 #   When specifying a different terminal, additional arguments are supported. In particular, you can
  86 #   append a specific title to the terminal and set it to "nofocus" in your WM config.
  87 #   E.g for alacritty and i3, you can set $NNN_TERMINAL to 'alacritty --title preview-tui' and add
  88 #   'no_focus [title="preview-tui"]' to your i3 config file.
  89 #
  90 # Shell: Bash (for environment manipulation through arrays)
  91 # Authors: Todd Yamakawa, Léo Villeveygoux, @Recidiviste, Mario Ortiz Manero, Luuk van Baal, @WanderLanz
  92
  93 # Configurable environment variables:
  94 NNN_SPLIT=${NNN_SPLIT:-}                                   # permanent split direction
  95 NNN_TERMINAL=${NNN_TERMINAL:-}                             # external terminal to be used
  96 NNN_SPLITSIZE=${NNN_SPLITSIZE:-50}                         # previewer split size percentage
  97 TMPDIR=${TMPDIR:-/tmp}                                     # location of temporary files
  98 ENVVARS=(
  99   "NNN_SCOPE=${NNN_SCOPE:-0}"                              # use scope
 100   "NNN_PISTOL=${NNN_PISTOL:-0}"                            # use pistol
 101   "NNN_ICONLOOKUP=${NNN_ICONLOOKUP:-0}"                    # use .iconlookup
 102   "NNN_PAGER=${NNN_PAGER:-less -P?n -R -C}"                # pager options
 103   "NNN_BATTHEME=${NNN_BATTHEME:-ansi}"                     # bat theme
 104   "NNN_BATSTYLE=${NNN_BATSTYLE:-numbers}"                  # bat style
 105   "NNN_PREVIEWWIDTH=${NNN_PREVIEWWIDTH:-1920}"             # width of generated preview images
 106   "NNN_PREVIEWHEIGHT=${NNN_PREVIEWHEIGHT:-1080}"           # height of generated preview images
 107   "NNN_PREVIEWDIR=${NNN_PREVIEWDIR:-$TMPDIR/nnn/previews}" # location of generated preview images
 108   "NNN_PREVIEWIMGPROG=${NNN_PREVIEWIMGPROG:-}"             # program used to preview images
 109   "NNN_PREVIEWVIDEO=${NNN_PREVIEWVIDEO:-}"                 # mpv backend used to preview video
 110 )
 111 # Non-configurable environment variables
 112 NNN_PARENT=${NNN_FIFO#*.}
 113 [ "$NNN_PARENT" -eq "$NNN_PARENT" ] 2>/dev/null || NNN_PARENT="" # Make empty if non-numeric
 114 ENVVARS+=(
 115   "PWD=$PWD"
 116   "PATH=$PATH"
 117   "NNN_FIFO=$NNN_FIFO"
 118   "FIFOPID=$TMPDIR/nnn-preview-tui-fifopid.$NNN_PARENT"
 119   "FIFOPATH=$TMPDIR/nnn-preview-tui-fifo.$NNN_PARENT"
 120   "PREVIEWPID=$TMPDIR/nnn-preview-tui-previewpid.$NNN_PARENT"
 121   "CURSEL=$TMPDIR/nnn-preview-tui-selection.$NNN_PARENT"
 122   "FIFO_UEBERZUG=$TMPDIR/nnn-preview-tui-ueberzug-fifo.$NNN_PARENT"
 123   "POSOFFSET=$TMPDIR/nnn-preview-tui-posoffset"
 124 )
 125
 126 trap '' PIPE
 127 exists() { type "$1" >/dev/null 2>&1 ;}
 128 pkill() { command pkill "$@" >/dev/null 2>&1 ;}
 129 prompt() { clear; printf "%b" "$@"; cfg=$(stty -g); stty raw -echo; head -c 1; stty "$cfg" ;}
 130 pidkill() {
 131     if [ -f "$1" ]; then
 132         PID="$(cat "$1" 2>/dev/null)" || return 1
 133         kill "$PID" >/dev/null 2>&1
 134         RET=$?
 135         wait "$PID" 2>/dev/null
 136         return $RET
 137     fi
 138     return 1
 139 }
 140
 141 start_preview() {
 142     if [ -e "${TMUX%%,*}" ] && tmux -V | grep -q '[ -][3456789]\.'; then
 143         NNN_TERMINAL=tmux
 144         exists mpv && tmux display -p '#{client_termfeatures}' | grep -q 'sixel' && ENVVARS+=("NNN_PREVIEWVIDEO=sixel")
 145     elif [ -n "$KITTY_LISTEN_ON" ]; then
 146         NNN_TERMINAL=kitty
 147         exists mpv && ENVVARS+=("NNN_PREVIEWVIDEO=kitty")
 148     elif [ -n "$WEZTERM_PANE" ]; then
 149         NNN_TERMINAL=wezterm
 150         exists mpv && ENVVARS+=("NNN_PREVIEWVIDEO=kitty")
 151     elif [ -z "$NNN_TERMINAL" ] && [ "$TERM_PROGRAM" = "iTerm.app" ]; then
 152         NNN_TERMINAL=iterm
 153         exists mpv && ENVVARS+=("NNN_PREVIEWVIDEO=sixel")
 154     elif [ -n "$WT_SESSION" ]; then
 155         NNN_TERMINAL=winterm
 156     else
 157         NNN_TERMINAL="${NNN_TERMINAL:-xterm}"
 158     fi
 159
 160     if [ -z "$NNN_SPLIT" ] && [ $(($(tput lines) * 2)) -gt "$(tput cols)" ]; then
 161         NNN_SPLIT='h'
 162     elif [ "$NNN_SPLIT" != 'h' ]; then
 163         NNN_SPLIT='v'
 164     fi
 165
 166     ENVVARS+=("NNN_TERMINAL=$NNN_TERMINAL" "NNN_SPLIT=$NNN_SPLIT" "QLPATH=$2" "PREVIEW_MODE=1")
 167     case "$NNN_TERMINAL" in
 168         iterm|winterm) # has to run in separate shell command: escape
 169             ENVVARS=("${ENVVARS[@]/#/\\\"}")
 170             ENVVARS=("${ENVVARS[@]/%/\\\"}")
 171             command="$SHELL -c 'env ${ENVVARS[*]} \\\"$0\\\" \\\"$1\\\"'" ;;
 172     esac
 173
 174     case "$NNN_TERMINAL" in
 175         tmux) # tmux splits are inverted
 176             ENVVARS=("${ENVVARS[@]/#/-e}")
 177             if [ "$NNN_SPLIT" = "v" ]; then split="h"; else split="v"; fi
 178             tmux split-window -l"$NNN_SPLITSIZE"% "${ENVVARS[@]}" -d"$split" -p"$NNN_SPLITSIZE" "$0" "$1" ;;
 179         kitty) # Setting the layout for the new window. It will be restored after the script ends.
 180             ENVVARS=("${ENVVARS[@]/#/--env=}")
 181             kitty @ goto-layout splits
 182             # Trying to use kitty's integrated window management as the split window.
 183             kitty @ launch --no-response --title "preview-tui" --keep-focus \
 184                 --cwd "$PWD" "${ENVVARS[@]}" --location "${NNN_SPLIT}split" "$0" "$1" ;;
 185         wezterm)
 186             export "${ENVVARS[@]}"
 187             if [ "$NNN_SPLIT" = "v" ]; then split="--horizontal"; else split="--bottom"; fi
 188             wezterm cli split-pane --cwd "$PWD" $split --percent "$NNN_SPLITSIZE" "$0" "$1" >/dev/null
 189             wezterm cli activate-pane-direction Prev ;;
 190         iterm)
 191             if [ "$NNN_SPLIT" = "h" ]; then split="horizontally"; else split="vertically"; fi
 192             osascript <<-EOF
 193             tell application "iTerm"
 194                 tell current session of current window
 195                     split $split with default profile command "$command"
 196                 end tell
 197             end tell
 198 EOF
 199             ;;
 200         winterm)
 201             if [ "$NNN_SPLIT" = "h" ]; then split="H"; else split="V"; fi
 202             wt -w 0 sp -$split -s"0.$NNN_SPLITSIZE" "$command" \; -w 0 mf previous 2>/dev/null ;;
 203         *)  if [ -n "$2" ]; then
 204                 env "${ENVVARS[@]}" QUICKLOOK=1 "$0" "$1" &
 205             else
 206                 # shellcheck disable=SC2086 # (allow arguments)
 207                 env "${ENVVARS[@]}" $NNN_TERMINAL -e "$0" "$1" &
 208             fi ;;
 209     esac
 210 }
 211
 212 toggle_preview() {
 213     export "${ENVVARS[@]}"
 214     if exists QuickLook.exe; then
 215         QLPATH="QuickLook.exe"
 216     elif exists Bridge.exe; then
 217         QLPATH="Bridge.exe"
 218     fi
 219     if pidkill "$FIFOPID"; then
 220         [ -p "$NNN_PPIPE" ] && printf "0" > "$NNN_PPIPE"
 221         pidkill "$PREVIEWPID"
 222         pkill -f "tail --follow $FIFO_UEBERZUG"
 223         if [ -n "$QLPATH" ] && stat "$1"; then
 224             f="$(wslpath -w "$1")" && "$QLPATH" "$f" &
 225         fi
 226     else
 227         [ -p "$NNN_PPIPE" ] && printf "1" > "$NNN_PPIPE"
 228         start_preview "$1" "$QLPATH"
 229     fi
 230 }
 231
 232 fifo_pager() {
 233     cmd="$1"
 234     shift
 235
 236     # We use a FIFO to access $NNN_PAGER PID in jobs control
 237     mkfifo "$FIFOPATH" || return
 238
 239     $NNN_PAGER < "$FIFOPATH" &
 240     printf "%s" "$!" > "$PREVIEWPID"
 241
 242     (
 243         exec > "$FIFOPATH"
 244         if [ "$cmd" = "pager" ]; then
 245             if exists bat; then
 246                 bat --terminal-width="$cols" --decorations=always --color=always \
 247                     --paging=never --style="$NNN_BATSTYLE" --theme="$NNN_BATTHEME" "$@" &
 248             else
 249                 $NNN_PAGER "$@" &
 250             fi
 251         else
 252             "$cmd" "$@" &
 253         fi
 254     )
 255
 256     rm "$FIFOPATH"
 257 }
 258
 259 # Binary file: show file info inside the pager
 260 print_bin_info() {
 261     printf -- "-------- \033[1;31mBinary file\033[0m --------\n"
 262     if exists mediainfo; then
 263         mediainfo "$1"
 264     else
 265         file -b "$1"
 266     fi
 267 }
 268
 269 handle_mime() {
 270     case "$2" in
 271         image/jpeg) image_preview "$cols" "$lines" "$1" ;;
 272         image/gif) generate_preview "$cols" "$lines" "$1" "gif" ;;
 273         image/vnd.djvu) generate_preview "$cols" "$lines" "$1" "djvu" ;;
 274         image/*) generate_preview "$cols" "$lines" "$1" "image" ;;
 275         video/*) generate_preview "$cols" "$lines" "$1" "video" ;;
 276         audio/*) generate_preview "$cols" "$lines" "$1" "audio" ;;
 277         application/font*|application/*opentype|font/*) generate_preview "$cols" "$lines" "$1" "font" ;;
 278         */*office*|*/*document*|*/*msword|*/*ms-excel) generate_preview "$cols" "$lines" "$1" "office" ;;
 279         application/zip) fifo_pager unzip -l "$1" ;;
 280         text/troff)
 281             if exists man; then
 282                 fifo_pager man -Pcat -l "$1"
 283             else
 284                 fifo_pager pager "$1"
 285             fi ;;
 286         *) handle_ext "$1" "$3" "$4" ;;
 287     esac
 288 }
 289
 290 handle_ext() {
 291     case "$2" in
 292         epub) generate_preview "$cols" "$lines" "$1" "epub" ;;
 293         pdf) generate_preview "$cols" "$lines" "$1" "pdf" ;;
 294         gz|bz2) fifo_pager tar -tvf "$1" ;;
 295         md) if exists glow; then
 296                 fifo_pager glow -s dark "$1"
 297             elif exists lowdown; then
 298                 fifo_pager lowdown -Tterm "$1"
 299             else
 300                 fifo_pager pager "$1"
 301             fi ;;
 302         htm|html|xhtml)
 303             if exists w3m; then
 304                 fifo_pager w3m "$1"
 305             elif exists lynx; then
 306                 fifo_pager lynx "$1"
 307             elif exists elinks; then
 308                 fifo_pager elinks "$1"
 309             else
 310                 fifo_pager pager "$1"
 311             fi ;;
 312         7z|a|ace|alz|arc|arj|bz|cab|cpio|deb|jar|lha|lz|lzh|lzma|lzo\
 313         |rar|rpm|rz|t7z|tar|tbz|tbz2|tgz|tlz|txz|tZ|tzo|war|xpi|xz|Z)
 314             if exists atool; then
 315                 fifo_pager atool -l "$1"
 316             elif exists bsdtar; then
 317                 fifo_pager bsdtar -tvf "$1"
 318             fi ;;
 319         *) if [ "$3" = "bin" ]; then
 320                fifo_pager print_bin_info "$1"
 321            else
 322                fifo_pager pager "$1"
 323            fi ;;
 324     esac
 325 }
 326
 327 preview_file() {
 328     clear
 329     # Trying to use pistol if it's available.
 330     if [ "$NNN_PISTOL" -ne 0 ] && exists pistol; then
 331         fifo_pager pistol "$1"
 332         return
 333     fi
 334
 335     # Trying to use scope.sh if it's available.
 336     if [ "$NNN_SCOPE" -ne 0 ] && exists scope.sh; then
 337         fifo_pager scope.sh "$1" "$cols" "$lines" "$(mktemp -d)" "True"
 338         return
 339     fi
 340
 341     # Use QuickLook if it's available.
 342     if [ -n "$QUICKLOOK" ]; then
 343         stat "$1" && f="$(wslpath -w "$1")" && "$QLPATH" "$f" &
 344         return
 345     fi
 346
 347     # Detecting the exact type of the file: the encoding, mime type, and extension in lowercase.
 348     encoding="$(file -bL --mime-encoding -- "$1")"
 349     mimetype="$(file -bL --mime-type -- "$1")"
 350     ext="${1##*.}"
 351     [ -n "$ext" ] && ext="$(printf "%s" "${ext}" | tr '[:upper:]' '[:lower:]')"
 352     lines=$(tput lines)
 353     cols=$(tput cols)
 354
 355     # Otherwise, falling back to the defaults.
 356     if [ -d "$1" ]; then
 357         cd "$1" || return
 358         if [ "$NNN_ICONLOOKUP" -ne 0 ] && [ -f "$(dirname "$0")"/.iconlookup ]; then
 359             [ "$NNN_SPLIT" = v ] && BSTR="\n"
 360             # shellcheck disable=SC2012
 361             ls -F --group-directories-first | head -n "$((lines - 3))" | "$(dirname "$0")"/.iconlookup -l "$cols" -B "$BSTR" -b " "
 362         elif exists tree; then
 363             fifo_pager tree --filelimit "$(find . -maxdepth 1 | wc -l)" -L 3 -C -F --dirsfirst --noreport
 364         elif exists exa; then
 365             exa -G --group-directories-first --colour=always
 366         elif exists eza; then # eza is a community fork of exa (exa is unmaintained)
 367             eza -G --group-directories-first --colour=always
 368         else
 369             fifo_pager ls -F --group-directories-first --color=always
 370         fi
 371         cd ..
 372     elif [ "${encoding#*)}" = "binary" ]; then
 373         handle_mime "$1" "$mimetype" "$ext" "bin"
 374     else
 375         handle_mime "$1" "$mimetype" "$ext"
 376     fi
 377 }
 378
 379 generate_preview() {
 380   if [ -n "$QLPATH" ] && stat "$3"; then
 381         f="$(wslpath -w "$3")" && "$QLPATH" "$f" &
 382   elif [ -n "$NNN_PREVIEWVIDEO" ] && [[ "$4" == +(gif|video) ]]; then
 383     [ "$4" = "video" ] && args=(--start=10% --length=4) || args=()
 384     video_preview "$1" "$2" "$3" "${args[@]}" && return
 385   elif [ ! -f "$NNN_PREVIEWDIR/$3.jpg" ] || [ -n "$(find -L "$3" -newer "$NNN_PREVIEWDIR/$3.jpg")" ]; then
 386         mkdir -p "$NNN_PREVIEWDIR/${3%/*}"
 387         case $4 in
 388             audio) ffmpeg -i "$3" -filter_complex "scale=iw*min(1\,min($NNN_PREVIEWWIDTH/iw\,ih)):-1" "$NNN_PREVIEWDIR/$3.jpg" -y ;;
 389             epub) gnome-epub-thumbnailer "$3" "$NNN_PREVIEWDIR/$3.jpg" ;;
 390             font) fontpreview -i "$3" -o "$NNN_PREVIEWDIR/$3.jpg" ;;
 391             gif) if [ -p "$FIFO_UEBERZUG" ] && exists convert; then
 392                     frameprefix="$NNN_PREVIEWDIR/$3/${3##*/}"
 393                     if [ ! -d "$NNN_PREVIEWDIR/$3" ]; then
 394                         mkdir -p "$NNN_PREVIEWDIR/$3"
 395                         convert -coalesce -resize "$NNN_PREVIEWWIDTH"x"$NNN_PREVIEWHEIGHT"\> "$3" "$frameprefix.jpg" ||
 396                         MAGICK_TMPDIR="/tmp" convert -coalesce -resize "$NNN_PREVIEWWIDTH"x"$NNN_PREVIEWHEIGHT"\> "$3" "$frameprefix.jpg"
 397                     fi
 398                     frames=$(($(find "$NNN_PREVIEWDIR/$3" | wc -l) - 2))
 399                     [ $frames -lt 0 ] && return
 400                     while true; do
 401                         for i in $(seq 0 $frames); do
 402                             image_preview "$1" "$2" "$frameprefix-$i.jpg"
 403                             sleep 0.1
 404                         done
 405                     done &
 406                     printf "%s" "$!" > "$PREVIEWPID"
 407                     return
 408                  elif [ -n "$NNN_PREVIEWVIDEO" ]; then
 409                     video_preview "$1" "$2" "$3" && return
 410                  else
 411                     image_preview "$1" "$2" "$3" && return
 412                  fi ;;
 413             image) if exists convert; then
 414                        convert "$3" -flatten -resize "$NNN_PREVIEWWIDTH"x"$NNN_PREVIEWHEIGHT"\> "$NNN_PREVIEWDIR/$3.jpg"
 415                    else
 416                        image_preview "$1" "$2" "$3" && return
 417                    fi ;;
 418             office) libreoffice --convert-to jpg "$3" --outdir "$NNN_PREVIEWDIR/${3%/*}"
 419                     filename="$(printf "%s" "${3##*/}" | cut -d. -f1)"
 420                     mv "$NNN_PREVIEWDIR/${3%/*}/$filename.jpg" "$NNN_PREVIEWDIR/$3.jpg" ;;
 421             pdf) pdftoppm -jpeg -f 1 -singlefile "$3" "$NNN_PREVIEWDIR/$3" ;;
 422             djvu) ddjvu -format=ppm -page=1 "$3" "$NNN_PREVIEWDIR/$3.jpg" ;;
 423             video) video_preview "$1" "$2" "$3" && return ;;
 424         esac
 425     fi
 426     if [ -f "$NNN_PREVIEWDIR/$3.jpg" ]; then
 427         image_preview "$1" "$2" "$NNN_PREVIEWDIR/$3.jpg"
 428     else
 429         fifo_pager print_bin_info "$3"
 430     fi
 431 } >/dev/null 2>&1
 432
 433 image_preview() {
 434     clear
 435     exec >/dev/tty
 436     if [ "$NNN_TERMINAL" = "kitty" ] && [[ "$NNN_PREVIEWIMGPROG" == +(|icat) ]]; then
 437         kitty +kitten icat --silent --scale-up --place "$1"x"$2"@0x0 --transfer-mode=stream --stdin=no "$3" &
 438     elif [ "$NNN_TERMINAL" = "wezterm" ] && [[ "$NNN_PREVIEWIMGPROG" == +(|imgcat) ]]; then
 439         wezterm imgcat "$3" &
 440     elif exists ueberzug && [[ "$NNN_PREVIEWIMGPROG" == +(|ueberzug) ]]; then
 441         ueberzug_layer "$1" "$2" "$3" && return
 442     elif exists catimg && [[ "$NNN_PREVIEWIMGPROG" == +(|catimg) ]]; then
 443         catimg "$3" &
 444     elif exists viu && [[ "$NNN_PREVIEWIMGPROG" == +(|viu) ]]; then
 445         viu -t "$3" &
 446     elif exists chafa && [[ "$NNN_PREVIEWIMGPROG" == +(|chafa) ]]; then
 447         chafa "$3" &
 448     elif exists img2sixel && [[ "$NNN_PREVIEWIMGPROG" == +(|img2sixel) ]]; then
 449         img2sixel -g "$3" &
 450     else
 451         fifo_pager print_bin_info "$3" && return
 452     fi
 453     printf "%s" "$!" > "$PREVIEWPID"
 454 }
 455
 456 video_preview() {
 457     clear
 458     exec >/dev/tty
 459     if [ -n "$NNN_PREVIEWVIDEO" ]; then
 460         mpv --no-config --really-quiet --vo="$NNN_PREVIEWVIDEO" --profile=sw-fast --loop-file --no-audio "$4" "$3" &
 461     else
 462         ffmpegthumbnailer -m -s0 -i "$3" -o "$NNN_PREVIEWDIR/$3.jpg" || rm "$NNN_PREVIEWDIR/$3.jpg" &
 463     fi
 464     printf "%s" "$!" > "$PREVIEWPID"
 465 }
 466
 467 ueberzug_layer() {
 468     [ -f "$POSOFFSET" ] && read -r x y < "$POSOFFSET"
 469     printf '{"action": "add", "identifier": "nnn_ueberzug", "x": %d, "y": %d, "width": "%d", "height": "%d", "scaler": "fit_contain", "path": "%s"}\n'\
 470         "${x:-0}" "${y:-0}" "$1" "$2" "$3" > "$FIFO_UEBERZUG"
 471 }
 472
 473 ueberzug_remove() {
 474     printf '{"action": "remove", "identifier": "nnn_ueberzug"}\n' > "$FIFO_UEBERZUG"
 475 }
 476
 477 winch_handler() {
 478     clear
 479     pidkill "$PREVIEWPID"
 480     if [ -p "$FIFO_UEBERZUG" ]; then
 481         pkill -f "tail --follow $FIFO_UEBERZUG"
 482         tail --follow "$FIFO_UEBERZUG" | ueberzug layer --silent --parser json &
 483     fi
 484     preview_file "$(cat "$CURSEL")"
 485 }
 486
 487 preview_fifo() {
 488     while read -r selection; do
 489         if [ -n "$selection" ]; then
 490             pidkill "$PREVIEWPID"
 491             [ -p "$FIFO_UEBERZUG" ] && ueberzug_remove
 492             [ "$selection" = "close" ] && break
 493             preview_file "$selection"
 494             printf "%s" "$selection" > "$CURSEL"
 495         fi
 496     done < "$NNN_FIFO"
 497     sleep 0.1 # make sure potential preview by winch_handler is killed
 498     pkill -P "$$"
 499 }
 500
 501 if [ "$PREVIEW_MODE" -eq 1 ] 2>/dev/null; then
 502     if exists ueberzug && [ "$NNN_TERMINAL" != "kitty" ] && [[ "$NNN_PREVIEWIMGPROG" == +(|ueberzug) ]]; then
 503         mkfifo "$FIFO_UEBERZUG"
 504         tail --follow "$FIFO_UEBERZUG" | ueberzug layer --silent --parser json &
 505     fi
 506
 507     preview_file "$PWD/$1"
 508     preview_fifo & WAITPID=$!
 509     printf "%s" "$!" > "$FIFOPID"
 510     printf "%s" "$PWD/$1" > "$CURSEL"
 511     trap 'winch_handler' WINCH
 512     trap 'rm "$PREVIEWPID" "$CURSEL" "$FIFO_UEBERZUG" "$FIFOPID" "$POSOFFSET" 2>/dev/null' INT HUP EXIT
 513     while kill -s 0 $WAITPID; do
 514       wait $WAITPID 2>/dev/null
 515     done
 516     exit 0
 517 else
 518     if [ ! -r "$NNN_FIFO" ]; then
 519         prompt "No FIFO available! (\$NNN_FIFO='$NNN_FIFO')\nPlease read Usage in '$0'."
 520     elif [ "$KITTY_WINDOW_ID" ] && [ -z "$TMUX" ] && [ -z "$KITTY_LISTEN_ON" ]; then
 521         prompt "\$KITTY_LISTEN_ON not set!\nPlease read Usage in '$0'."
 522     else
 523         toggle_preview "$1" &
 524     fi
 525 fi