pxart flood

flood FILE[:frame] KEY x,y [--diagonal]

usage: pxart flood [-h] [--diagonal] [-o O] [--dry-run] file key at

  flood FILE[:frame] KEY x,y [--diagonal]
      Bucket-fill the region of one key that touches x,y.

positional arguments:
  file
  key         a palette key, or '.' to erase
  at

options:
  -h, --help  show this help message and exit
  --diagonal
  -o O
  --dry-run   print what the edit says and a diff of the file it would change; write nothing

      Bucket fill: repaint the region of x,y's key that touches x,y through sides (4-connected),
      or corners too with --diagonal.

See also, in pxart help all: DRAWING (FILE[:SEL], KEY ('.' erases), clipping, 'painted N
  px'); EDITING (-o OUT gets the whole file, only changed lines are rewritten, 'no change');
  FORMAT: selecting frames (FILE:SEL, an unnamed grid's name, zsh's "${F}:sel").

pxart help all has the whole reference, pxart help TOPIC one part of it.

This is the output of pxart help flood. The other drawing commands and their shared notes are in pxart help DRAWING.