Replace tmux copy/scrollback mode with Kakoune

Recipes & Guides
1 
# Make our own copy-mode with Kakoune!
bind -Tpane-menu N capture-pane -S- -E- -J -b copy-mode \; \
    new-window -n copy-mode -d '\
      file=$(mktemp) ; \
      tmux save-buffer -b copy-mode "$file" ; \
      tmux delete-buffer -b copy-mode ; \
      command kak -e "\
         edit $file ;\
         exec gj ;\
         set-option buffer readonly true ;\
         set-option window filetype tmux-copy ;\
         rename-buffer *tmux-copy* ;\
         " ; \
      rm -f "$file" ; \
      tmux swap-pane -s :copy-mode.0 -t : ; \
    ' \; \
    swap-pane -s :copy-mode.0 -t :

Of course, you’ll need to bind to your existing copy-mode key, not my weird pane-menu thing.

2

Here’s an updated version which captures ANSI escapes and tries to put the cursor close to where it was. It’s more complicated, and could use some more love, but I think it’s finally better than above:

# Make our own copy-mode with Kakoune!
bind -Tpane-menu N run-shell 'tmux set-buffer -b copy-pane-id "#D"' \; \
    new-window -n copy-mode -d '\
      pane_id="$(tmux show-buffer -b copy-pane-id)" ;\
      file=$(mktemp) ;\
      tmux capture-pane -t "${pane_id}" -S- -E- -J -e -p >"$file" ;\
      cursor_y=$(tmux display-message -t "${pane_id}" -p "#{cursor_y}") ;\
      cursor_x=$(tmux display-message -t "${pane_id}" -p "#{cursor_x}") ;\
      pane_height=$(tmux display-message -t "${pane_id}" -p "#{pane_height}") ;\
      line_count="$(wc -l "$file" |awk "{print \$1}")" ;\
      sel_line=$(( line_count - ( pane_height - cursor_y ) + 1 )) ;\
      printf "sel = %s\n" "$line_count" >>/tmp/debug.log ;\
      cursor="${sel_line}.${cursor_x},${sel_line}.${cursor_x}" ;\
      printf "cursor = %s\n" "$cursor" >>/tmp/debug.log ;\
      command kak -e "\
         edit $file ;\
         exec gj ;\
         try %{\
            ansi-render ;\
         } catch %{\
            exec -draft %{%s\x1B[\d;]+m<ret><a-d>} ;\
         } ;\
         write ;\
         set-option buffer readonly true ;\
         set-option window filetype tmux-copy ;\
         rename-buffer *tmux-copy* ;\
         select $cursor ;\
         " ; \
      rm -f "$file" ; \
      tmux swap-pane -s :copy-mode.0 -t : ; \
    ' \; \
    swap-pane -s :copy-mode.0 -t :
1 Like
3

Of course, you’ll need to bind to your existing copy-mode key, not my weird pane-menu thing.

When you say “my weird pane-menu” thing what do you mean exactly? I’d love to put this to use in my own tmux config, but I’m not very well versed with tmux’s config language.

4

@EpocSquadron I have bind -Tpane-menu N where you might just use bind c (for example) to make <leader>c copy mode.

5

In the first version that you proposed @eraserhd , why not dumping the pane to stdout and directly pipe it to kak? I understand that it does not handle ansi, but as a quick solution, what are the drawbacks compared to what you proposed? What is the point of having a temporary file?

bind-key [ send-keys 'tmux capture-pane -S - -p | kak'
6

Few modifications I made:

  • avoid run-shell
  • set user option @copy-pane-id instead of setting buffer
  • split-window -Z instead of new-window in order to avoid referring to pane index :copy-mode.0 because index 0 can be invalid in case of set-option -wg pane-base-index 1.
bind-key F10 set-option -F @copy-pane-id "#D" \; \
    split-window -Z '\
      pane_id="$(tmux show-option -v @copy-pane-id)" ;\
      file=$(mktemp) ;\
      tmux capture-pane -t "${pane_id}" -S- -E- -J -e -p >"$file" ;\
      cursor_y=$(tmux display-message -t "${pane_id}" -p "#{cursor_y}") ;\
      cursor_x=$(tmux display-message -t "${pane_id}" -p "#{cursor_x}") ;\
      pane_height=$(tmux display-message -t "${pane_id}" -p "#{pane_height}") ;\
      line_count="$(wc -l "$file" |awk "{print \$1}")" ;\
      sel_line=$(( line_count - ( pane_height - cursor_y ) + 1 )) ;\
      cursor="${sel_line}.${cursor_x},${sel_line}.${cursor_x}" ;\
      command kak -e "\
         edit $file ;\
         exec gj ;\
         try %{\
            ansi-render ;\
         } catch %{\
            exec -draft %{%s\x1B[\d;]+m<ret><a-d>} ;\
         } ;\
         write ;\
         set-option buffer readonly true ;\
         set-option window filetype tmux-copy ;\
         rename-buffer *tmux-copy* ;\
         select $cursor ;\
         " ;\
      unlink "$file" ;\
    '

tmux’s capture-pane has option -b buffer-name, so I think it’s possible to avoid creating temporary file by capturing pane directly into a buffer but I’m lazy to implement this.