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.
Vertical is a story property: every frame of a thread is vertical or
horizontal together, a frame threaded onto a story takes its direction,
and frames split off by threading or breaking a thread keep theirs.
Type > Story Direction is type.storyDirection {vertical} (checked in the
menu) for the stories of the text selection or selected frames;
object.textFrameOptions {vertical} and frame.create {vertical} set the
frames' stories. Documents that stored Vertical on the frame open with
each story taking its first frame's direction. IDML StoryOrientation is
read into and written from the story, beside its column direction
(StoryDirection), which stays a separate setting.
An .xlsx cell reference far from the others no longer allocates the whole
range before the cell cap (billions of cells, out of memory), and long
column names can't overflow. IDML import doesn't trust zip part sizes for
up-front allocation and adds header/footer counts saturating. Tagged Text
and IDML export use let-else; the font fallback has a compiled-in last
resort. These crates deny the panicking lints.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
aiongg
Brandon Thomas