usePosterLayout has always computed a real layout: the map narrowed by the legend
column and inset by the margins, the title strip and the footer strip. Nothing in
the exporter ever read it. The map was rastered at full page size -- edge to edge,
across the margins and both bands -- and the title, legend and footer were then
composited on top of that image. The legend lay over the map it describes, and
there were no bands at all.
What kept it hidden is that PosterPreview.vue DOES honour layout.map, so the
on-screen preview has always shown the intended design and only the exported file
was wrong. A preview is not evidence for an export.
The obvious fix breaks a different product. country-posters embeds this renderer's
output as a full-sheet <img> inside its own packet page, beneath the packet's own
title, so chrome that is on by default prints a second header and footer within
their page. UPG-100's packet does not call this renderer at all and was never at
risk -- checked rather than assumed. So the composed sheet is requested with
spec.layout === 'poster', and every existing caller, which sets none, keeps what
it had.
That guarantee is stronger than "equivalent": with no layout the renderer passes
the SAME px OBJECT it always did to the rasteriser and composites no sheet, so the
untouched path is unchanged by identity, not merely by value. The check asserts
exactly that, by executing the decision with four real caller shapes -- including
country-posters' A4 at 150 DPI -- rather than reading the source for a promise.
Its second negative test is the ruling's own failure mode: make defaultPosterSpec
set the layout and country-posters is named as silently opted in.
A sheet with no room left for a map after its margins, bands and legend column
falls back to full-bleed and says so, because silence there is the bug above.
Simple Research's export asks for the layout explicitly.
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