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SVG 2 vector graphics model

Document status: reviewed. Canonical source.

Summary

SVG 2 defines an XML vocabulary for nested graphics elements, coordinate systems, geometry, paint, text, reuse and accessibility metadata. SVG element identity uses the XML id attribute. The g element groups descendants without introducing NUIF component or layout semantics.

Evidence

  • SVG 2 §5.1–5.2 defines an SVG document fragment and the svg element. The viewBox and viewport establish coordinate-system mappings; they are not equivalent to an authored responsive layout rule. https://www.w3.org/TR/SVG2/struct.html#NewDocument and https://www.w3.org/TR/SVG2/coords.html#ViewBoxAttribute (retrieved 2026-08-29).
  • SVG 2 §10 defines rect, circle, ellipse, line, polyline and polygon as basic shapes. A rect is axis-aligned in the current user coordinate system; an ellipse is defined by cx, cy, rx and ry. https://www.w3.org/TR/SVG2/shapes.html (retrieved 2026-08-29).
  • SVG 2 §12 defines text layout through text, tspan and text positioning attributes. SVG text permits per-character positioning, text paths and shaping behavior beyond NUIF profile zero. https://www.w3.org/TR/SVG2/text.html (retrieved 2026-08-29).
  • SVG 2 §13 makes fill and stroke presentation properties available to shape and text elements. CSS cascading and inheritance apply, so a computed paint cannot be attributed to one source span without cascade analysis. https://www.w3.org/TR/SVG2/painting.html and https://www.w3.org/TR/SVG2/styling.html (retrieved 2026-08-29).
  • SVG 2 §16 permits WAI-ARIA attributes and the role attribute on SVG elements. This surface can carry NUIF role and accessible-name correspondences, subject to the SVG Accessibility API Mappings. https://www.w3.org/TR/SVG2/struct.html#WAIARIAAttributes (retrieved 2026-08-29).

NUIF relevance

Borrow the basic-shape geometry, sRGB presentation attributes, containment order, XML identity and accessibility attributes for a bounded vector profile.

Adapt svg, g, rect, ellipse and text into NUIF surface, container, shape and text entities. A generated profile requires explicit data-nuif-* metadata for document identity, stable entity identity, pinned font identity and authored sizing intent. Static numeric attributes can retain byte-span correspondence.

Reject a claim that arbitrary SVG is a lossless semantic import. Paths, transforms, CSS cascade, paint servers, clipping, masks, filters, animation, scripts, external resources, per-character text positioning and <use> instancing require separate profiles. Unknown XML can be retained as source but cannot be classified as lossless NUIF semantics without a declared extension.