fzf-previews

   1 #!/usr/bin/env bash
   2 # fzf-ueberzogen.sh is a wrapper script which allows to use ueberzug with fzf.
   3 # Copyright (C) 2019  Nico Baeurer
   4
   5 # This program is free software: you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation, either version 3 of the License, or
   8 # (at your option) any later version.
   9
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  17 readonly BASH_BINARY="$(which bash)"
  18 readonly REDRAW_COMMAND="toggle-preview+toggle-preview"
  19 readonly REDRAW_KEY="µ"
  20 declare -r -x DEFAULT_PREVIEW_POSITION="right"
  21 declare -r -x UEBERZUG_FIFO="$(mktemp --dry-run --suffix "fzf-$$-ueberzug")"
  22 declare -r -x PREVIEW_ID="preview"
  23
  24
  25 function STORE_TERMINAL_SIZE_IN {
  26     # Usage: STORE_TERMINAL_SIZE_IN
  27     #           lines_variable columns_variable
  28     [[ ! -v "$1" || ! -v "$2" ]] && return 1
  29     < <(</dev/tty stty size) \
  30         read "$1" "$2"
  31 }
  32
  33
  34 function STORE_FZF_HEIGHT_IN {
  35     # Usage: STORE_FZF_HEIGHT_IN
  36     #           fzf_height_lines_variable
  37     #           terminal_lines fzf_height fzf_min_height
  38     [[ $# -ne 4 || ! -v "$1" ]] && return 1
  39     local -n _fzf_height_lines="$1"
  40     local terminal_lines="$2"
  41     local fzf_height_text="$3"
  42     local fzf_min_height="$4"
  43
  44     _fzf_height_lines="${fzf_height_text}"
  45
  46     if [[ "${fzf_height_text}" == *"%" ]]; then
  47         ((_fzf_height_lines=(terminal_lines * ${fzf_height_text%\%}) / 100))
  48     else
  49         ((_fzf_height_lines=_fzf_height_lines > terminal_lines ? terminal_lines :_fzf_height_lines))
  50     fi
  51
  52     ((_fzf_height_lines=fzf_min_height > _fzf_height_lines
  53                         ? fzf_min_height : _fzf_height_lines))
  54 }
  55
  56
  57 function STORE_FZF_OFFSET_IN {
  58     # Usage: STORE_FZF_OFFSET_IN
  59     #           fzf_offset_y_variable
  60     #           terminal_lines fzf_height fzf_start_offset_y
  61     [[ $# -ne 4 || ! -v "$1" ]] && return 1
  62     local -n _fzf_offset_y="$1"
  63     local terminal_lines="$2"
  64     local fzf_height="$3"
  65     local fzf_start_offset_y="$4"
  66
  67     # Two cases:
  68     # 1. There isn't enough space, so fzf will print blank lines.
  69     #    -> OFFSET_Y = terminal height - required lines
  70     # 2. There is enough space -> OFFSET_Y = START_OFFSET_Y
  71     ((_fzf_offset_y=terminal_lines - fzf_height))
  72     ((_fzf_offset_y=_fzf_offset_y < fzf_start_offset_y
  73                     ? _fzf_offset_y : fzf_start_offset_y))
  74 }
  75
  76
  77 function STORE_PREVIEW_POSITION_IN {
  78     # Usage: STORE_PREVIEW_POSITION_IN
  79     #           preview_y_variable preview_x_variable
  80     #           preview_position fzf_offset_y fzf_height
  81     #           terminal_width preview_height preview_width
  82     [[ $# -ne 8 || ! -v "$1" || ! -v "$2" ]] && return 1
  83     local -n _preview_y="$1"
  84     local -n _preview_x="$2"
  85     local preview_position="$3"
  86     local fzf_offset_y="$4"
  87     local fzf_height="$5"
  88     local terminal_width="$6"
  89     local preview_height="$7"
  90     local preview_width="$8"
  91
  92     case "${preview_position}" in
  93         left|up|top)
  94             _preview_x=2
  95             _preview_y=$((1 + fzf_offset_y))
  96             ;;
  97         right)
  98             _preview_x=$((terminal_width - preview_width - 2))
  99             _preview_y=$((1 + fzf_offset_y))
 100             ;;
 101         down|bottom)
 102             _preview_x=2
 103             _preview_y=$((fzf_offset_y + fzf_height - preview_height - 1))
 104             ;;
 105     esac
 106 }
 107
 108
 109 function DRAW_PREVIEW {
 110         local preview_path=""
 111
 112         if test -f "${@}/001.jpg"; then
 113                 preview_path="${@}/001.jpg"
 114         elif test -f "${@}/001.png"; then
 115                 preview_path="${@}/001.png"
 116         else
 117                 return
 118         fi
 119
 120     # Usage: DRAW_PREVIEW path
 121     local -A add_preview_command=( \
 122         [identifier]="${PREVIEW_ID}" \
 123         [scaler]=contain \
 124         [path]="${preview_path}")
 125     ADD_PLACEMENT add_preview_command
 126 }
 127
 128
 129 function CLEAR_PREVIEW {
 130     # Usage: CLEAR_PREVIEW
 131     REMOVE_PLACEMENT "${PREVIEW_ID}"
 132 }
 133
 134
 135 function IDENTITY_RECT {
 136     # Usage: IDENTITY_RECT
 137     #           placement_rect_variable
 138     [[ $# -ne 1 ]] && return 1
 139 }
 140
 141
 142 function ADD_PLACEMENT {
 143     # Usage: ADD_PLACEMENT
 144     #           add_command_variable [adjust_rect_function]
 145     # references can't be checked.. -v doesn't seem to support associative arrays..
 146     local terminal_lines= terminal_columns=
 147     local fzf_height= fzf_offset_y=
 148     local preview_y= preview_x=
 149     local preview_height="${LINES}" preview_width="${COLUMNS}"
 150     STORE_TERMINAL_SIZE_IN \
 151         terminal_lines terminal_columns
 152     STORE_FZF_HEIGHT_IN \
 153         fzf_height \
 154         "$terminal_lines" "${FZF_HEIGHT}" "${FZF_MIN_HEIGHT}"
 155     STORE_FZF_OFFSET_IN \
 156         fzf_offset_y \
 157         "$terminal_lines" "${fzf_height}" "${FZF_START_OFFSET_Y}"
 158     STORE_PREVIEW_POSITION_IN \
 159         preview_y preview_x \
 160         "${PREVIEW_POSITION:-${DEFAULT_PREVIEW_POSITION}}" \
 161         "${fzf_offset_y}" "${fzf_height}" "${terminal_columns}" \
 162         "${preview_height}" "${preview_width}"
 163
 164     local _add_command_nameref="$1"
 165     local -n _add_command="${_add_command_nameref}"
 166     local adjust_rect_callback="${2:-IDENTITY_RECT}"
 167     local -A adjusted_placement_rect=( \
 168         [y]="${preview_y}" [x]="${preview_x}" \
 169         [height]="${preview_height}" [width]="${preview_width}")
 170     "${adjust_rect_callback}" adjusted_placement_rect
 171     _add_command[action]=add
 172     _add_command[x]="${adjusted_placement_rect[x]}"
 173     _add_command[y]="${adjusted_placement_rect[y]}"
 174     _add_command[width]="${adjusted_placement_rect[width]}"
 175     _add_command[height]="${adjusted_placement_rect[height]}"
 176
 177     >"${UEBERZUG_FIFO}" \
 178         declare -p "${_add_command_nameref}"
 179 }
 180
 181
 182 function REMOVE_PLACEMENT {
 183     # Usage: REMOVE_PLACEMENT placement-id
 184     [[ $# -ne 1 ]] && return 1
 185     >"${UEBERZUG_FIFO}" \
 186         declare -A -p _remove_command=( \
 187         [action]=remove [identifier]="${1}")
 188 }
 189
 190
 191 function is_option_key [[ "${@}" =~ ^(\-.*|\+.*) ]]
 192 function is_key_value [[ "${@}" == *=* ]]
 193
 194
 195 function store_options_map_in {
 196     # Usage: store_options_map_in
 197     #           options_map_variable options_variable
 198     # references can't be checked.. -v doesn't seem to support associative arrays..
 199     [[ $# -ne 2 || ! -v "$2" ]] && return 1
 200     local -n _options_map="${1}"
 201     local -n _options="${2}"
 202
 203     for ((i=0; i < ${#_options[@]}; i++)); do
 204         local key="${_options[$i]}" next_key="${_options[$((i + 1))]:---}"
 205         local value=true
 206         is_option_key "${key}" || \
 207             continue
 208         if is_key_value "${key}"; then
 209             <<<"${key}" \
 210                 IFS='=' read key value
 211         elif ! is_option_key "${next_key}"; then
 212             value="${next_key}"
 213         fi
 214         _options_map["${key}"]="${value}"
 215     done
 216 }
 217
 218
 219 function process_options {
 220     # Usage: process_options command-line-arguments
 221     local -a "default_options=(${FZF_DEFAULT_OPTS})"
 222     local -a script_options=("${@}")
 223     local -A mapped_options
 224     store_options_map_in mapped_options default_options
 225     store_options_map_in mapped_options script_options
 226
 227     local cursor_y= cursor_x=
 228     store_cursor_position_in cursor_y cursor_x
 229     # If fzf is used as completion tool we will get the position of the prompt.
 230     # If it's normally used we get the position the output will be displayed at.
 231     # If it's normally used we need to subtract one to get the position of the prompt.
 232     ((cursor_y=cursor_x != 1 ? cursor_y : cursor_y - 1))
 233     declare -g -r -x FZF_START_OFFSET_Y="${cursor_y}"
 234     declare -g -r -x PREVIEW_POSITION="${mapped_options[--preview-window]%%:[^:]*}"
 235     declare -g -r -x FZF_HEIGHT="${mapped_options[--height]:-100%}"
 236     declare -g -r -x FZF_MIN_HEIGHT="${mapped_options[--min-height]:-10}"
 237 }
 238
 239
 240 function store_cursor_position_in {
 241     # Usage: store_cursor_pos_in
 242     #           y_variable x_variable
 243     # based on https://github.com/dylanaraps/pure-bash-bible#get-the-current-cursor-position
 244     [[ ! -v "$1" || ! -v "$2" ]] && return 1
 245     </dev/tty &>/dev/tty \
 246         IFS='[;' \
 247         read -p $'\e[6n' -d R -rs _ "${1}" "${2}" _
 248 }
 249
 250
 251 function start_ueberzug {
 252     # Usage: start_ueberzug
 253     mkfifo "${UEBERZUG_FIFO}"
 254     <"${UEBERZUG_FIFO}" \
 255         ueberzug layer --parser bash --silent &
 256     # prevent EOF
 257     3>"${UEBERZUG_FIFO}" \
 258         exec
 259 }
 260
 261
 262 function finalise {
 263     # Usage: finalise
 264     3>&- \
 265         exec
 266     &>/dev/null \
 267         rm "${UEBERZUG_FIFO}"
 268     &>/dev/null \
 269         kill $(jobs -p)
 270 }
 271
 272
 273 function print_on_winch {
 274     # Usage: print_on_winch text
 275     # print "$@" to stdin on receiving SIGWINCH
 276     # use exec as we will only kill direct childs on exiting,
 277     # also the additional bash process isn't needed
 278     </dev/tty \
 279         exec perl -e '
 280             require "sys/ioctl.ph";
 281             while (1) {
 282                 local $SIG{WINCH} = sub {
 283                     ioctl(STDIN, &TIOCSTI, $_) for split "", join " ", @ARGV;
 284                 };
 285                 sleep;
 286             }' \
 287             "${@}" &
 288 }
 289
 290
 291 function export_functions {
 292     # Usage: export_functions
 293     # Exports all functions with a name
 294     # which only consists of underscores,
 295     # figures, upper case charactars
 296     local -a function_names="( $(compgen -A function) )"
 297
 298     for function_name in "${function_names[@]}"; do
 299         [[ "${function_name}" =~ ^[A-Z0-9_]+$ ]] && {
 300             export -f "${function_name}"
 301         }
 302     done
 303 }
 304
 305
 306 if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
 307     trap finalise EXIT
 308     process_options "${@}"
 309     # print the redraw key twice as there's a run condition we can't circumvent
 310     # (we can't know the time fzf finished redrawing it's layout)
 311     print_on_winch "${REDRAW_KEY}${REDRAW_KEY}"
 312     start_ueberzug
 313
 314     export_functions
 315     SHELL="${BASH_BINARY}" \
 316         fzf --preview "DRAW_PREVIEW {}" \
 317             --preview-window "${DEFAULT_PREVIEW_POSITION}" \
 318             --bind "${REDRAW_KEY}:${REDRAW_COMMAND}" \
 319             "${@}"
 320 fi