Layout: inside/outside floats swap sides on even pages; Page Setup shows mirror margins (#1181) (#1239)

* Layout: inside/outside floats swap sides on even pages; Page Setup shows mirror margins (#1181)

Floats aligned inside or outside, or placed relative to the inside or
outside margin, were always put as on an odd page, so shapes Word puts
in a book's outside margin all came out on the right. They now follow
the page they're on (ECMA-376 ST_AlignH, ST_RelFromH): on an even page
the inside is the right side. Floating tables (w:tblpXSpec) too.

With mirrored margins, even pages are laid out as odd ones and then
shifted; float positions now allow for that shift, so floats placed
from the page edge stay put (the "known limit" in #452) and the left
and right margin areas are each page's own.

Mirrored margins read from a file were invisible in the UI: the Margins
menu ticks Mirrored when they're on, and Page Setup gets a Mirror
margins check box (labelling the margins Inside and Outside), applied
through a new `mirror` param of layout.margins.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* i18n: Mirror margins in every catalog

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: lloyd <lloyd@stackworx.io>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>

docs/layout-parity.md

@@ -1,6 +1,6 @@
 # Layout and pagination parity with Microsoft Word
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-14 · **Change:** trivial (STYLEREF running headers per page, #775; previously trivial: PAGEREF in headers and footers shows its bookmark's page, #1477; previously trivial: a paragraph continued into the next column or page wraps around that column's shapes, #1374; previously trivial: PAGE fields in a paragraph split across pages show the page they are on, #1352; previously trivial: symbol-font text drawn as Unicode symbols, #776; previously trivial: large-table scrolling measured and fixed, #811; previously trivial: text boxes use their own margins; Resize shape to fit text never cuts text, #743; previously trivial: complex-script shaping and Myanmar line breaking, #604; previously trivial: body page totals, table-cell footnotes and bookmark link pages fixed, #450 #451 #455; previously major: first version; line breaking, pagination and object placement checked against Word's behaviour from the layout source on origin/main) · **Target:** Microsoft Word (Microsoft 365) for Mac 16.113.4
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-14 · **Change:** trivial (floats aligned inside/outside or placed in the inside/outside margin swap sides on even pages; page-relative floats no longer move with mirrored text, #1181; previously trivial: STYLEREF running headers per page, #775; previously trivial: PAGEREF in headers and footers shows its bookmark's page, #1477; previously trivial: a paragraph continued into the next column or page wraps around that column's shapes, #1374; previously trivial: PAGE fields in a paragraph split across pages show the page they are on, #1352; previously trivial: symbol-font text drawn as Unicode symbols, #776; previously trivial: large-table scrolling measured and fixed, #811; previously trivial: text boxes use their own margins; Resize shape to fit text never cuts text, #743; previously trivial: complex-script shaping and Myanmar line breaking, #604; previously trivial: body page totals, table-cell footnotes and bookmark link pages fixed, #450 #451 #455; previously major: first version; line breaking, pagination and object placement checked against Word's behaviour from the layout source on origin/main) · **Target:** Microsoft Word (Microsoft 365) for Mac 16.113.4
 
 A document only "opens correctly" if its pages break where Word breaks them: the same lines, the
 same page count, footnotes and pictures on the same pages. This checklist covers line breaking,
@@ -53,7 +53,7 @@ font can't match Word's metrics.
 | Page borders (from page edge or text), page colour, watermark | ✅ | | — |
 | Line numbers (restart per page/section, count by) | ✅ | | — |
 | Vertical page alignment | ✅ | | — |
-| Gutter, mirror margins, book fold, 2 pages per sheet | 🟡 | gutter and mirror margins (even pages put the inside margin and gutter on the right, #452; page-relative floats move with the text); book fold missing | 2–3 |
+| Gutter, mirror margins, book fold, 2 pages per sheet | 🟡 | gutter and mirror margins (even pages put the inside margin and gutter on the right, #452; page-relative floats stay put, and inside/outside alignment and margins follow the page side, #1181); book fold missing | 2–3 |
 | Vertical text (`tbRl`) in sections and text boxes; cell text direction | ✅ | cell text direction (#245); text-box text direction (#369); vertical sections (`tbRl`/`btLr`, #491): the page's text area turned, lines top to bottom stacking right to left, ideographs, kana and Hangul upright, Latin on its side, caret and clicks through the turn. Missing: OpenType `vert` alternates (punctuation is moved, not substituted), arrow keys along vertical lines, upright pictures take turned room | 2–4 |
 | Gutter, mirror margins, book fold, 2 pages per sheet | 🟡 | gutter and mirror margins; book fold missing | 2–3 |
 | Document grid (`w:docGrid`, lines per page, characters per line) | 🟡 | #391, #401: line grid snaps line heights to whole pitches (text centred in them; `w:snapToGrid` off opts a paragraph out); character grid puts East Asian characters on the character pitch (`linesAndChars`) or all text (`snapToChars`), Latin text proportional; View › Gridlines draws it. Not yet: run-level `w:snapToGrid`, grid in headers/footers, paragraph spacing in grid lines, Word's exact glyph placement in a cell | 1–2 |
@@ -158,6 +158,7 @@ No overall parity estimate changes from these probes.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-13 | trivial | Floats and floating tables aligned inside/outside, or placed in the inside/outside margin, swap sides on even pages; with mirrored margins, page-relative floats keep their place and left/right margin areas are each page's own (#1181) |
 | 2026-10-13 | trivial | PAGEREF in headers and footers shows its bookmark's page (#1477) |
 | 2026-10-13 | trivial | A shape or picture dragged into another column anchors there, so the text in that column wraps around it (#884) |
 | 2026-10-13 | trivial | On a page with footnotes, a paragraph that ends there keeps its space after above the footnote separator; if it doesn't fit, its last line (and, with widow control, one more) goes to the next page with the note. Pages without notes are unchanged (#1116) |