pixel-art

Pixel Art

Convert any image into retro pixel art, then optionally animate it into a short MP4 or GIF with era-appropriate effects (rain, fireflies, snow, embers).

Two scripts ship with this skill:

• scripts/pixel_art.py — photo → pixel-art PNG (Floyd-Steinberg dithering)
• scripts/pixel_art_video.py — pixel-art PNG → animated MP4 (+ optional GIF)

Each is importable or runnable directly. Presets snap to hardware palettes when you want era-accurate colors (NES, Game Boy, PICO-8, etc.), or use adaptive N-color quantization for arcade/SNES-style looks.

When to Use

• User wants retro pixel art from a source image
• User asks for NES / Game Boy / PICO-8 / C64 / arcade / SNES styling
• User wants a short looping animation (rain scene, night sky, snow, etc.)
• Posters, album covers, social posts, sprites, characters, avatars

Workflow

Before generating, confirm the style with the user. Different presets produce very different outputs and regenerating is costly.

Step 1 — Offer a style

Call clarify with 4 representative presets. Pick the set based on what the user asked for — don't just dump all 14.

Default menu when the user's intent is unclear:

clarify(
    question="Which pixel-art style do you want?",
    choices=[
        "arcade — bold, chunky 80s cabinet feel (16 colors, 8px)",
        "nes — Nintendo 8-bit hardware palette (54 colors, 8px)",
        "gameboy — 4-shade green Game Boy DMG",
        "snes — cleaner 16-bit look (32 colors, 4px)",
    ],
)

When the user already named an era (e.g. "80s arcade", "Gameboy"), skip clarify and use the matching preset directly.

Step 2 — Offer animation (optional)

If the user asked for a video/GIF, or the output might benefit from motion, ask which scene:

clarify(
    question="Want to animate it? Pick a scene or skip.",
    choices=[
        "night — stars + fireflies + leaves",
        "urban — rain + neon pulse",
        "snow — falling snowflakes",
        "skip — just the image",
    ],
)

Do NOT call clarify more than twice in a row. One for style, one for scene if animation is on the table. If the user explicitly asked for a specific style and scene in their message, skip clarify entirely.

Step 3 — Generate

Run pixel_art() first; if animation was requested, chain into pixel_art_video() on the result.

Preset Catalog

Named palettes live in scripts/palettes.py (see references/palettes.md for the complete list — 28 named palettes total). Any preset can be overridden:

pixel_art("in.png", "out.png", preset="snes", palette="PICO_8", block=6)

Scene Catalog (for video)

Invocation Patterns

Python (import)

import sys
import os
sys.path.insert(0, os.path.expanduser("~/.hermes/skills/creative/pixel-art/scripts"))
from pixel_art import pixel_art
from pixel_art_video import pixel_art_video

# 1. Convert to pixel art
pixel_art("/path/to/photo.jpg", "/tmp/pixel.png", preset="nes")

# 2. Animate (optional)
pixel_art_video(
    "/tmp/pixel.png",
    "/tmp/pixel.mp4",
    scene="night",
    duration=6,
    fps=15,
    seed=42,
    export_gif=True,
)

CLI

cd ~/.hermes/skills/creative/pixel-art/scripts

python pixel_art.py in.jpg out.png --preset gameboy
python pixel_art.py in.jpg out.png --preset snes --palette PICO_8 --block 6

python pixel_art_video.py out.png out.mp4 --scene night --duration 6 --gif

Pipeline Rationale

Pixel conversion:

1. Boost contrast/color/sharpness (stronger for smaller palettes)
2. Posterize to simplify tonal regions before quantization
3. Downscale by block with Image.NEAREST (hard pixels, no interpolation)
4. Quantize with Floyd-Steinberg dithering — against either an adaptive N-color palette OR a named hardware palette
5. Upscale back with Image.NEAREST

Quantizing AFTER downscale keeps dithering aligned with the final pixel grid. Quantizing before would waste error-diffusion on detail that disappears.

Video overlay:

• Copies the base frame each tick (static background)
• Overlays stateless-per-frame particle draws (one function per effect)
• Encodes via ffmpeg libx264 -pix_fmt yuv420p -crf 18
• Optional GIF via palettegen + paletteuse

Dependencies

• Python 3.9+
• Pillow (pip install Pillow)
• ffmpeg on PATH (only needed for video — Hermes installs package this)

Pitfalls

• Pallet keys are case-sensitive ("NES", "PICO_8", "GAMEBOY_ORIGINAL").
• Very small sources (<100px wide) collapse under 8-10px blocks. Upscale the source first if it's tiny.
• Fractional block or palette will break quantization — keep them positive ints.
• Animation particle counts are tuned for ~640x480 canvases. On very large images you may want a second pass with a different seed for density.
• mono_green / mono_amber force color=0.0 (desaturate). If you override and keep chroma, the 2-color palette can produce stripes on smooth regions.
• clarify loop: call it at most twice per turn (style, then scene). Don't pepper the user with more picks.

Verification

• PNG is created at the output path
• Clear square pixel blocks visible at the preset's block size
• Color count matches preset (eyeball the image or run Image.open(p).getcolors())
• Video is a valid MP4 (ffprobe can open it) with non-zero size

Attribution

Named hardware palettes and the procedural animation loops in pixel_art_video.py are ported from pixel-art-studio (MIT). See ATTRIBUTION.md in this skill directory for details.