EA parity: generated SVGs must be fully identical to EA's own SVG export (fonts, connectors, geometry)

[ronaldtse]

Goal

SVGs generated by ea svg / ea spa must be fully identical to what Enterprise Architect builds — same structure, geometry, connectors, and fonts — so that generated SPA output is visually indistinguishable from EA's own SVG export.

Ea::Svg::Parity::Suite (lib/ea/svg/parity/suite.rb) already exists to drive this: it renders every diagram and compares against per-diagram EA reference SVGs (<eaid>.svg in a reference directory). It currently measures element counts only (rect, polygon, path, text), and the repository ships zero EA reference exports.

Tracked defects blocking parity

• SVG connector arrows originate from wrong port: renderer ignores source_edge/source_duid (and QEA builder never sets them) #52 — connector arrows originate from the wrong port: renderer ignores source_edge/source_duid (and the QEA builder never sets them); stored waypoints endpoints unused.
• SVG fonts are theme defaults, not the model's: QEA builder drops font_size, elements render Arial 9px/13px instead of EA fonts #53 — fonts are theme defaults (Arial 9px / Yu Gothic UI 13px), not the model's fonts: QEA builder drops font_size; FontResolver always falls back to theme.
• TextRenderer TypeError (nil into Float) skips SVG for ~8% of PLATEAU CG3 diagrams and crashes ea svg --all #51 — TextRenderer TypeError: can't convert nil into Float on some diagrams: crashes ea svg --all outright, and 297/3,702 diagrams in the PLATEAU CG3 model render as metadata-only in the SPA.

What "done" means

1. A representative set of EA-exported reference SVGs committed as parity fixtures (export from EA for a subset of the public PLATEAU models in metanorma/plateau-models — class diagrams, views with connectors, diagrams with notes/labels).
2. Parity::Checker extended beyond element counts: per-element geometry deltas, font face/size/weight, connector endpoints docked at the stored ports, arrowhead placement.
3. Parity::Suite runs in CI against the fixtures and fails on deltas.
4. All of TextRenderer TypeError (nil into Float) skips SVG for ~8% of PLATEAU CG3 diagrams and crashes ea svg --all #51, SVG connector arrows originate from wrong port: renderer ignores source_edge/source_duid (and QEA builder never sets them) #52, SVG fonts are theme defaults, not the model's: QEA builder drops font_size, elements render Arial 9px/13px instead of EA fonts #53 resolved against that gate.

First step

Export reference SVGs from EA for a small fixed subset (e.g. 10 diagrams spanning the defect cases) and drop them into the parity reference directory — the suite can then produce a baseline delta report to size the remaining work.