The decoder handles all five PNG colour types including palette (type 3) via PLTE lookup; the encoder covers only four, because RawImage carries no palette of its own. Small and self-contained, and the payoff is real for document work: indexed colour is substantially smaller than truecolour for the flat-colour images typical of diagrams and screenshots that end up embedded in documents.
Evidence
src/image/png-encode.ts: "RawImage's channels/alpha combination maps onto these four (never 3, palette -- this encoder never emits an indexed-colour image, since RawImage carries no palette of its own)." decodePng handles colorType === 3 via a PLTE chunk lookup in src/image/png-decode.ts.
Affected packages: byte-codec
Surfaced by a full-repository gap survey (feature/fidelity/write-support gaps), cross-checked against the existing issue history so it does not duplicate prior work.
The decoder handles all five PNG colour types including palette (type 3) via PLTE lookup; the encoder covers only four, because RawImage carries no palette of its own. Small and self-contained, and the payoff is real for document work: indexed colour is substantially smaller than truecolour for the flat-colour images typical of diagrams and screenshots that end up embedded in documents.
Evidence
Affected packages:
byte-codecSurfaced by a full-repository gap survey (feature/fidelity/write-support gaps), cross-checked against the existing issue history so it does not duplicate prior work.