# Display top 3 lines as the fixed header
fzf --preview 'bat --style=full --color=always {}' --preview-window '~3'

# Works well with the streaming preview
fzf --preview-window 'follow:~2' --preview 'for i in $(seq 100000); do
  # Clear preview content every 300 lines and print header
  (( i % 300 == 1 )) && echo -e "\x1b[2J$i ~ $((i + 300))" && echo '---'
  echo "$i"
  sleep 0.01
done'

# Preview with bat, matching line in the middle of the window below
# the fixed header of the top 3 lines
#
#   ~3    Top 3 lines as the fixed header
#   +{2}  Base scroll offset extracted from the second field
#   +3    Extra offset to compensate for the 3-line header
#   /2    Put in the middle of the preview area
#
git grep --line-number '' |
  fzf --layout reverse --delimiter : \
      --preview 'bat --style=full --color=always --highlight-line {2} {1}' \
      --preview-window '~3:+{2}+3/2'