epiphany/crates/epiphany-render-svg

epiphany-render-svg

Agent I's SVG renderer behind the Epiphany RenderIR interface (spec Chapter 7): turns a ResolvedLayoutIR into well-formed SVG 1.1, drawing each glyph from genuine Bravura SMuFL data — inline outline <path>s by default (GlyphMode::PathOutline), or <text> set in an @font-face-embedded Bravura subset (GlyphMode::EmbeddedFont). It is the visible end of the v0 Score → layout IR pipeline.

Status

The Score → layout IR → SVG pipeline renders recognizable notation — clefs, noteheads at clef-relative staff positions, accidentals, key/time signatures, rests, barlines, and the staff lines and stems that connect them. Output is golden-locked against both the interface-only stub solver and Agent I's real epiphany-engrave solver (whose horizontal spacing pass re-spaces the glyphs), and the layout round-trip (criterion 6) runs through both. What the renderer itself guarantees, independent of engraving quality: real Bravura glyphs, provenance preserved to the score graph, output XML-valid and deterministic. The renderer consumes any solver's ResolvedLayoutIR.

Demo

# Render a fixture to SVG (stub solver by default):
cargo run -p epiphany-render-svg --example render_fixture -- \
    ten_measure_single_staff > out.svg

# Drive Agent I's engrave solver instead, to bisect renderer-vs-solver:
cargo run -p epiphany-render-svg --example render_fixture -- \
    ten_measure_single_staff --solver=real > out.svg

# Use the embedded-font glyph mode (<text> + @font-face) instead of inline paths:
cargo run -p epiphany-render-svg --example render_fixture -- \
    ten_measure_single_staff --glyph-mode=embedded > out.svg

Fixtures: ten_measure_single_staff, valid_score_rich, valid_score. Stats and diagnostics go to stderr; the SVG goes to stdout.

Library

use epiphany_render_svg::{render, RenderOptions};

let out = render(&resolved_layout_ir, &RenderOptions::default());
assert!(out.is_well_formed());
println!("{}", out.svg);

render is pure and deterministic. RenderOptions controls SVG-encoding choices only (display scale, margin, provenance attributes, and glyph_mode — inline PathOutline vs EmbeddedFont) — nothing that changes engraving.

Bundled Bravura data

Two generated artifacts come from the official OFL Bravura.otf via epiphany-glyphs's tools/extract_bravura_outlines.py — the font is not vendored, only the generated Rust is committed. The outlines moved to epiphany-glyphs in T4-pre W2 (a canvas renderer needs them too, so they are a shared asset rather than a renderer-private one); the font subset stayed here, because an embeddable OTF is a renderer concern:

• epiphany-glyphs/src/outlines_generated.rs — the inline glyph outlines (geometry-only, so byte-stable across fontTools versions). This crate reaches them through epiphany_glyphs::outline, and re-exports bundled_glyph_count/smufl_codepoint unchanged;
• src/font_subset_generated.rs — a base64 OTF subset (just the pipeline's glyphs) for GlyphMode::EmbeddedFont. As a Modified Version, its primary font name is renamed off the Reserved Font Name "Bravura" per the OFL; a content BLAKE3 + decoded length are committed alongside as an integrity lock.

Bravura is © Steinberg Media Technologies GmbH under the SIL Open Font License 1.1 (../epiphany-glyphs/tools/OFL.txt, which travels with the redistributed outlines); both artifacts are redistributed under the same license. To regenerate both (the subset step also needs the blake3 package):

cd crates/epiphany-glyphs/tools
python3 -m venv .venv && . .venv/bin/activate && pip install fonttools blake3
python3 extract_bravura_outlines.py \
    --font-out ../../epiphany-render-svg/src/font_subset_generated.rs \
    > ../src/outlines_generated.rs