Platform Cat — workshop

32×22 pixel sprite — a chunky black platform cat with a 2-frame idle bob-and-blink and a 4-frame grooming wash-up, drawn from an editable character map.

The unofficial eighth member of the Straphanger / Stand Clear / nyc-conductor / Subway Rat / Platform Pigeon / Subway Cockroach platform: a sooty black cat sitting on its haunches, front paw tucked, tail wrapped around toward the front — the one who’s seen everything and clocks out at the end of the shift like everyone else. Two animation loops — an idle (still body, a slow tail-tip lift, blink) and a grooming wash-up (four-frame paw raise: chest, cheek, ear, back down) — plus amber eyes and tiny pink toe beans, because even a soot-black transit cat gets one bright detail.

Reuse

export/cat-sheet.png — 192×22 strip, six 32×22 frames in order: idle-0, idle-1, groom-0, groom-1, groom-2, groom-3.
cat-{idle,groom}-*.png — the individual frames.
cat@8x.png — prescaled 8× hero shot for docs/previews.

Render at integer scales with nearest-neighbor filtering or the edges smear. Idle plays at 2 fps, groom at 6 fps (ANIMATIONS in the module carries both). The cat is drawn near-black — pick a mid-to-light background behind it (the demo uses a warm platform gray) or it disappears the way it would on an actual subway platform at 2am.

Source

No .aseprite — the canonical source is source/platform-cat.mjs: a framework-free ES module holding the pixel grids as character maps (one char per pixel, palette at the top). Edit a grid and regenerate everything with:

node source/render.mjs

(needs site/node_modules installed — the script resolves Playwright from there.) That one command rewrites export/, media/, thumb.png, and the demo’s bundled copy of the module, so nothing drifts.

How the frames are built

A frame is up to three layers composited on the 32×22 canvas, back to front: TAIL (a full-width layer, fixed anchor row — the rump silhouette already covers everything above it, so the tail only needs to fill the open gap underneath: drop below the body, sweep right toward the front paws, curl the tip up into the pocket between rump and paw), BODY (the sitting silhouette — head, ears, torso, tucked front leg and paw, all baked into one static grid, drawn at the frame’s bob offset — the only layer that moves vertically), then PAW (a small local grid placed at a per-frame {left, top}, present only in groom frames — the raised mitt that sells the wash-up, same “small piece travels alone” trick platform-pigeon uses for its head-bob strut). Idle frames carry no paw entry at all — that absence is “not grooming right now,” not a fourth empty-pattern lookup.

Gotchas

validateGrids() throws if any row isn’t exactly the right width, a frame references a missing tail pattern or eye color, or a paw offset would push the mitt off the canvas — call it after editing, or just run render.mjs, which calls it first.
demo/platform-cat.js is generated. Edit source/platform-cat.mjs and re-render.
The tail lives entirely in the gap between the rump and the front paw at bottom of frame — route any redesign through that same pocket, or the body silhouette (drawn after the tail) will just paint over it.
The demo draws the sprite from the character maps at runtime, fine at this size. A game should blit cat-sheet.png instead.

Port notes

paintFrame is ~25 lines of grid walking with no DOM dependency beyond a 2D context — same shape as platform-pigeon’s (fixed body + a small traveling local grid) — so a DragonRuby port translates directly: keep the grids as strings, map cells to args.outputs.solids, or just consume cat-sheet.png as a spritesheet with source_x = frame * 32.