serializeSvg
Serializes root into SVG text in the module's /v1 format.
The root's GroupNode.bounds becomes the viewBox and is required; a nested group's non-null bounds cannot be encoded and is dropped with a warning. Numbers are written at full stored Double precision, never quantized — the file keeps the raw components, and canonical equality is rebuilt on load by the shapes' rounded identity — so parseSvg(serializeSvg(scene)) == scene. Output is canonical: fixed attribute order, lowercase hex colors, shortest round-trippable numbers. Canonical per platform, though — Double.toString differs between targets — so never compare serialized text across platforms.
Degenerate CGA states persist faithfully: imaginary and inside-out circles ride k:flags, and an infinite line writes its world-border crossings as display endpoints with recognition riding k:type — data loss is never the persistence layer's call. The exception is a shape the format cannot place at all: a line at infinity, or a dipole whose endpoints lie at infinity, is skipped with a warning.
Return
The complete SVG document text.
Parameters
The scene to write; its bounds must be non-null.
Throws
when root's bounds is null.