Four more Tailwind classes, all four verified against draw.io's own source in
public/drawio rather than against a prose reference — which is how three earlier
exclusions turned out to be wrong:
rounded-* mxShape.js:1172-1189 — absoluteArcSize=1 switches arcSize to
absolute pixels and halves it, so the same class is the same
corner on every box. Previously excluded as 'percentage only'
shadow-sm..xl mxShape.js:505-535 — getShadowStyle reads five independent
params, not one flag, so Tailwind's offset+blur rungs map one
to one. Previously excluded as 'six sizes collapse to one'
line-through mxConstants.js:2054 FONT_STRIKETHROUGH: 8, read at both
mxText.js:723 and :1040. The bitmask has four bits, not three
border-none the only one of the four that adds something previously
inexpressible: a fill with no outline
Also fixes an edge style growing 76 characters per re-layout, without bound. The
router recomputes ports on every pass, and appending them to a style recovered
from the canvas — which already carried the previous pass's eight port keys —
grew the string forever. draw.io resolves duplicates last-wins so the arrow
always looked right; a byte-identity check is what caught it.
Two traps found while wiring the readback, both the same shape: a value the
THEME emits being recorded as one the model asked for. strokeColor=none from a
filled or ghost role, and rounded=0 from the fallback style. Either one would
outlive a set_role, since that clears style but keeps text.
Deliberately not included, with reasons in tw.ts: per-side borders and per-corner
radius (both would take the shape slot, and what a node IS matters more than
which of its edges show), per-side padding (draw.io's keys pad the label, not the
room left for children), text-shadow (a bare flag with no offset or blur),
opacity (Tailwind's is any integer, not a scale), tracking/uppercase/leading
(absent from draw.io — zero grep hits, not merely coarse).
615 tests, 90 new. Browser-verified: four shadow rungs visibly differ, radius is
real pixels, terminator + rounded-lg becomes a small-cornered rounded rect while
an untouched terminator stays a stadium.
The expressiveness gap between engine output and hand-written XML came down
to two missing capabilities, both generic:
- Block layout inside a box: nested containers already existed, but there was
no way to split space by weight, pin a child to an edge, or tighten padding.
Added grow (flex-grow over the parent's leftover flow-axis space, TeX's
glue), align (start/center/end/stretch on the cross axis) and pad
(per-group interior padding). All three round-trip via dai_grow/dai_align/
dai_pad markers.
- Inline rich text: labels already render HTML (html=1 on every style, esc()
entities decode back), but the measure pass counted markup as text. The
visibleText() strip makes autoBoxSize measure what draw.io draws: <br> is a
line, other inline tags are invisible.
Graphviz (HTML-like table labels), D2 (grid containers + markdown-in-shape)
and TeX (box+glue) converged on exactly this design: nested boxes for block
structure, proportional glue, a small inline set for text — never full HTML.
Prompts teach the composition with a comparison-card recipe; verified by
rebuilding the CoT poster end to end in the real editor.
