A character the applied font lacks is drawn as that font's missing-glyph
box (its .notdef, gid 0), on screen and in PDF, and Preflight lists the
characters by font ("Missing glyphs in <family> <style>: …", an error,
at most 20 named). A .notdef without an outline is drawn as a hollow box
across its advance, so a missing character never disappears. PDF draws
.notdef glyphs as paths, which PDF/A and PDF/UA accept. Kenten marks are
set in their text's font the same way.
The document setting Draw Missing Glyphs from Fallback Fonts
(DocSettings::glyph_fallback; Preferences > Composition,
document.preferences {glyphFallback}, undoable) draws them from fallback
fonts instead (the language-aware chains, then any font; kenten marks
from a fallback font, else a bullet). It is off in new documents and
IDML imports and on in files saved before it existed, which keep
drawing as they did. A missing font's substitute always uses fallback
fonts. The composition cache's signature includes the setting. Tests
whose Arabic comes from a fallback font turn the setting on.
The fonts in a document's Document Fonts folder are registered under a
font scope that the document holds while it is open (Document::font_scope,
runtime only; DocState keeps the scope alive and closes it when the last
copy of the state goes: file.close, closing a tab, revert, a book
chapter's export, the session ending). Composition, preflight, font.list,
Package and the font menus, Glyphs panel and previews look fonts up
through FontDb::scoped(scope): the document's own faces first, then the
shared ones. Other open documents don't see them, and two documents with
fonts of the same name each set text in their own. Composite fonts'
member fonts and the fallback for kenten marks are looked up the same
way.
Font files stay in memory for the session (FaceRef keeps faces for the
process); a document opened again reuses the faces of its unchanged files
(same path, length and modification time) instead of reading them again.
The composition cache's signature includes the scope; the word cache and
the outline and PDF font caches are keyed by face. Variable font
instances are kept per base face.
A family's installed faces join the shared fonts all at once, and a
face two lookups load at the same time is kept once, so a parallel
fallback lookup never takes a family's bold before its regular has
loaded.
Characters the primary font lacks try a fallback chain by language
before the language-blind search: Japanese (the craft-fonts Japanese
faces first, Mincho first), Simplified Chinese (also plain Chinese),
Traditional Chinese and Korean each list their macOS, Windows and Linux
system families. Hangul, kana and Bopomofo pick their language's chain
whatever the character language; ideographs and CJK punctuation follow
it, and keep today's fallback without a CJK language. Chain families
load from the system font catalog the first time they are needed.
designcraft_fonts::testing (feature `testing`) builds synthetic fonts
with a given family name and coverage for tests.
Port the CJK1 and AR1 changes from 3ecdb78 and de83cdc onto current main. Resolve translation and font-stack conflicts by retaining main localization and craft-fonts integration while preserving all typesetting code, tests, and documentation.
Validation: all six CI gates passed, including 616 tests and WASM checks.
aiongg