document.export {format: "png8" | "gif"} reduces the art to a palette of at most `colors`
(2–256) entries: median cut over a 15-bit histogram refined by k-means (perceptual,
selective or adaptive weighting), or the web-safe, black-and-white or grey palettes; art
with that many colours or fewer keeps them exactly. Dithering is Floyd–Steinberg diffusion,
an 8×8 ordered pattern or noise, with an amount. Pixels under half opacity become one
transparent entry; partly transparent edges blend over the matte. PNG-8 is an indexed PNG
(PLTE, tRNS, 1–8 bits per pixel, Adam7); GIF is a GIF89a (optionally interlaced). Both are in
document.formats, Export As (PNG-8 / GIF Options dialogs) and Export for Screens.
document.formats' writable list and the MCP export tool's format enum gain gif and png8
(their tests list them).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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