Paint

Code-drawn watercolor

You paint by writing a short Python function against paintkit.Canvas, an OpenCV watercolor toolkit bundled with this skill. Geometry is seeded, so you can look at the output, fix the two worst things, and re-render the same painting with only your edit changed.

Read reference.md in this skill directory once before your first scene. It documents every primitive. examples/full_scene.py is a worked 18-element scene that uses every primitive; skim it for patterns before starting. Do not paste either into the conversation.

Workflow

Run each step with bash_tool. This skill is mounted read-only at .codex/skills/examples/paint; write outputs to your working directory.

1. Write the scene to a file in your working directory:

   cat > scene.py <<'EOF'
   from paintkit import Canvas, hex_rgb
   
   def paint(cv: Canvas):
       cv.paper_texture(0.05)
       cv.wash(0, int(cv.h * 0.55), hex_rgb("#a7c4d8"), hex_rgb("#e8d7b8"),
               alpha=0.8, mottling=0.4)
       # ... more primitives, back to front
   EOF
   

2. Render a quick preview:

   python .codex/skills/examples/paint/render.py scene.py -o preview.png --scale 0.5 --seed 1
   

3. Look at it. Call the view tool on preview.png. bash_tool returns only stdout, so without this step you never see what you drew.

4. Critique and revise. Name the two things that read worst (a colour that fights the light, a shape that sits in the wrong plane, an edge that should be lost) and edit only those lines in scene.py. Re-render and look again. Two or three rounds is usually enough.

5. Render full size and deliver:

   python .codex/skills/examples/paint/render.py scene.py -o out.png --width 1600 --height 900 --seed 1
   

   Then call present_files on out.png and scene.py. The scene file is the editable source; keep it so "make the sky darker" is an edit, not a new painting.

Keeping the transcript clean

Write and edit scene.py through bash_tool (heredoc, or a short Python -c that rewrites the file). Do not paste scene source into the chat as prose; a collapsed tool call is a few lines in the transcript.

Painting well

Work back to front and light to dark. Reserve whites by leaving paper unpainted or with a white outline; there is no white pigment. Two thin watercolor_blob layers read better than one heavy flat_shape. Distance is cool, low-contrast, wet, soft; foreground is warm, dark, dry, hard-edged. Use cv.rng for any procedural placement so the scene stays seeded.

Budget

The container has one CPU and a 300 s wall clock per call. A full 18-element scene renders in about a second at 1600×900. Use --scale 0.5 while iterating.