Code Art 2D
You write the art as text (PixelSpec JSON, portable SVG, rig, FX, material, layout or parallax
specs); the scripts render, check and package it. No image model is involved. It is a declared art
source (art_source: "code"), not a placeholder.
Use when
- The user explicitly asks for code-drawn art: a PixelSpec or SVG sprite, palette variants drawn in code, a code rig, code FX, a seam-proven autotile set, a code-made layout, stylized parallax or ambient loops.
route_media.py prints no-route (exit 3): no API key is configured and no local image or video route exists. Say so, and offer to add a key or a CLI as well.- Pose and layout guides that help an image model (support material, not final art).
Do not use when
- Any art request while an image or video route exists and the user did not ask for code art: generate2dsprite, generate2dmap or video2dsprite generate it.
- Painterly, organic or identity-rich art, likenesses, portraits, HD-2D plates or textured terrain; realistic fire, smoke or water.
- Never trace licensed characters into specs.
Capability check (once per session)
Run python "<skill-dir>/../generate2dmedia/scripts/route_media.py" resolve --kind image (or --kind video): when it names a route, the image or video skill takes the request unless the user asked for code art. forge_doctor.py in the same folder shows the full picture. If encoding.stdout fails, set PYTHONUTF8=1. For SVG work also run svg_render.py doctor --report <new.json> once per machine.
Art source
This skill is the explicit-only last resort of the route order: the API when a key is configured, then the local image tools, then code art, only when the user asks for it or no route exists. Never substitute it silently for generated art. Before you draw, check what code art can and cannot draw well in style-envelope.md (its table describes strengths, not the route order), and tell the user when a request needs an image model. Disclose every result: "code-drawn, no image model" (codeart-meta.json records "art_source": "code"); never present it as image-model output.
Host notes
- Codex: this skill is explicit-only;
image_gen and route_media.py make the art unless the user asks for code art. Look at review sheets with view_image.
- Claude Code: use it only on request or after
no-route. Look at every preview-*.png and review/*.png with Read before you report; run tools with Bash; <skill-dir> is ${CLAUDE_SKILL_DIR}.
- Grok: runs the same Python tools; its native image tools make the art unless the user asks for code art.
Commands
Run each tool as one line from the user's project root: python "<skill-dir>/scripts/<tool>.py" .... <skill-dir> is this skill's folder; sibling skills sit beside it (--build-clips calls <skill-dir>/../generate2dsprite/scripts/build_animation_clips.py). Keep specs and outputs inside the project. Every tool writes a new --output-dir: it refuses an existing one and publishes only a complete result; with --strict-qc a failed check publishes nothing. Success prints one JSON line; errors print error: ... and exit 1; usage errors exit 2. Examples to copy: examples/.
Dependencies: numpy and Pillow for everything; PixelSpec rendering and pixel_qa.py need nothing else. SVG art also needs one rasterizer: resvg-py (python -m pip install "resvg-py>=0.5,<0.6", preferred), the resvg-js CLI on PATH, or Chrome/Edge (set CHROME_PATH) (rasterizers.md). Never PyMuPDF, skia-python or cairosvg: they silently ignore crispEdges, <style>, clipPath or gradients. fx_verify.mjs needs node.
Hello sprite
- Write
gem.pixelspec.json (the "Hello sprite" block in pixelspec.md).
python "<skill-dir>/scripts/render_pixelspec.py" --spec gem.pixelspec.json --output-dir out/gem-v1 --preview-scale 8 --strict-qc- Open
out/gem-v1/preview-x8.png; the frames are in out/gem-v1/<variant>/frames/.
- Tell the user it is code-drawn (no image model).
Pipeline
| Need | Route |
|---|
| Pixel character, prop or FX with palette variants | PixelSpec (pixelspec.md), then render_pixelspec.py --spec <spec> --output-dir <new> --build-clips --strict-qc; review with pixel_qa.py |
| Flat vector character, prop, UI or icon set | portable SVG with palette classes (svg-profile.md), then svg_render.py render --svg <svg> --palette <palette.json> --output-dir <new> --zoom N |
| Crisp pixel art drawn with SVG shapes | svg_render.py render --crisp --zoom N --strict-qc |
| Check an SVG before rendering | svg_render.py lint --svg <svg> --profile portable (add --compile --palette <p>) |
| Small character that walks, idles or attacks with planted feet | rig SVG plus a rig_anim.v1 file (rig-animation.md), then rig_animate.py --rig <svg> --anim <json> --output-dir <new> --build-clips --strict-qc; look at review/*.png |
| Slash, sparks, impact ring, hit flash, dust, projectile | fx.v1 spec (fx-language.md), then fx_build.py --spec <json> --output-dir <new> --build-clips --export-runtime; baked frames for pixel games, fx-runtime.mjs for gameplay-timed FX (fx-runtime-contract.md) |
| Check an fx.v1 runtime | node "<skill-dir>/scripts/fx_verify.mjs" <module.mjs> --report <file> |
| Terrain transitions, roads meeting water, paths over ground, walls and ledges | material spec, then autotile_build.py --material-spec <json> --output-dir <new> --strict-qc (Wang-16, three materials, blob-47, bevel; tiles-and-maps.md) |
| An image-tool texture inside exact tile masks | autotile_build.py --material-texture NAME=PATH --quantize-textures (one tile that wraps) |
| Playable top-down map: roads, props, exits, collision, reachability | layout_build.py --spec <layout.json> --output-dir <new> --preview --strict-qc (--tiles <tileset manifest> for real tiles); open debug.png (layouts-and-parallax.md) |
| Stylized parallax background | parallax_build.py --spec <parallax.json> --output-dir <new> --validate --sweep-frames 49; review sweep-sheet.png |
| Ambient motion on a static plate | ambient_bake.py --plate <png> --spec <effects.json> --output-dir <new> --preview --strict-qc; encode with generate2dmap scene_motion.py |
| QA any pixel frames | pixel_qa.py --input "<glob>" --palette <palette, spec or codeart-meta.json> --review <new.png> --onion --strict --report <new.json> |
Hand-offs: clips go to generate2dsprite export_engine.py (never generate2dsprite.py process); a layout's map_bundle.v2 goes to generate2dmap map_bundle.py validate, map_nav.py check and export_tiled.py / export_godot.py / export_ldtk.py.
Rules
- SVG (portable profile, enforced by lint): root width and height equal an integer viewBox (1 unit = 1 logical pixel); colours via
class="c-NAME"; bones rotate with transform="rotate(a cx cy)"; no <text>, <image>, feTurbulence, feDisplacementMap or mix-blend-mode; pixel art adds shape-rendering="crispEdges" and no gradients, masks, filters or opacity.
- Tilesets are seam-proven before they are published: tiles assembled from the atlas are compared pixel for pixel with an independent global render over every adjacency the set allows.
--strict-qc never passes without that proof.
- Fold empty FX tail frames before building clips; the builder refuses fully transparent frames.
- Side-view walk and run cycles: give the near and far legs a clear value contrast (the far leg two or more shades darker, never two darks that read alike) and keep the arms or forelegs visible (not hidden under a scarf, cape or bag).
render_pixelspec.py warns half_cycle_duplicates when frame i and i+n/2 of a walk/run clip share a silhouette (IoU >= 0.95); fix the legs, or pass --allow-duplicate-half-cycle only after the review sheet shows the stride reads.
- generate2dsprite
sheet_qc.py frames on code-drawn frames (art_source=code): identity_residual and torso_drift are advisory, since the head and root are fixed in code; judge them by eye, and treat near_duplicates and leg_alternation as real.
Acceptance
Look at the preview and review sheets at game size and 1x before reporting (style-envelope.md has the review loop). Quote the QA status and failed checks from the JSON summary.
Report every WARN or FAIL check verbatim (id, value, threshold, files) from each published QA envelope; never say "all checks passed" when any published envelope has a warn. Deliver specs, rendered frames or tiles, clips or bundles, codeart-meta.json and the disclosure line. Data contracts: references/schemas/codeart.schema.json.