pxart outline

outline FILE[:frame] --key K [--outside | --inside] [--lit L [--selective]] [--light nw] [--corners] [--preview P.png] [--min-alpha A] [--pad]

usage: pxart outline [-h] --key KEY [--lit LIT] [--selective] [--light {n,ne,e,se,s,sw,w,nw}]
                     [--preview PREVIEW] [--inside | --outside] [--corners] [--min-alpha A]
                     [--pad] [-o O] [--dry-run]
                     file

  outline FILE[:frame] --key K [--outside | --inside] [--lit L [--selective]] [--light nw]
          [--corners] [--preview P.png] [--min-alpha A] [--pad]
      Outline a frame's shape with a key, optionally lit on the side facing the light (--lit).

positional arguments:
  file

options:
  -h, --help                     show this help message and exit
  --key KEY
  --lit LIT                      lighter key for the edges facing the light (selective outline)
  --selective                    the same as --lit L alone: light the outline selectively (needs --lit)
  --light {n,ne,e,se,s,sw,w,nw}
  --preview PREVIEW              render the result to this PNG; write nothing else
  --inside
  --outside
  --corners
  --min-alpha A                  the shape is the keys at alpha A or more (in the base or a variant); fainter px aren't: the outline paints over those it lands on, and those in a hole of the shape are the hole's, so the ones along its edge get the outline key
  --pad                          first grow each frame 1px of '.' on the sides the shape touches (the same for every frame, so an animation stays aligned; pivots move with the art, and a group with no pivots gets ones that keep every frame's art where anim drew it), so the outline closes there
  -o O
  --dry-run                      print what the edit says and a diff of the file it would change; write nothing

      Outline the frame's shape (every pixel that draws in some variant; with --min-alpha A, at
      alpha A+). --outside (the default) paints the empty pixels touching the shape on a side
      (--pad: first grow the frame 1px where the shape meets its edge, pivots and all); --inside
      repaints the shape's own pixels that have an empty side (off the frame is empty). Sides only
      is the pixel-perfect rule: a diagonal edge gets a 1px staircase and a square corner is cut,
      so no doubled (L-shaped) corners; --corners also takes the pixels touching only at a corner
      (square corners, a 2px staircase). Selective outline (--lit L, or --selective --lit L):
      outline pixels facing the light get L (a darker tone of the material), the rest K. Facing:
      an outline pixel's outward normal (shade's, over 2px) dotted with the light's direction;
      above 0 is lit, so a nw light lights the top and left edges and a 45-degree edge (ne, sw)
      stays K. --light and --preview as for shade. Prints "changed 12 px: 6->o, 6->l" (by key; px
      that had it already don't count).

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 outline. The other drawing commands and their shared notes are in pxart help DRAWING.