1.12 registers no `GetStringHeight` (`script/button.rs`: `0x782390` reads the label's height
instead) and ClassicAPI backports it, so `compat/classic_api/frame.rs` is its home. That file had
it on its own not-built list under "needs per-line layout facts the host measurer is not asked for
today" — true of `GetNumLines` and `GetWrappedWidth`, and not of this one: the whole-string height
is the other half of the number `GetStringWidth` already reads. `measure::current_measure` now owns
the staleness rule for both, so the two cannot disagree about when a measure has gone stale, and a
changed string still reads 0 rather than the previous string's height.
It is not cosmetic. AceGUI-3.0 calls it **unguarded** — `AceGUIWidget-Label.lua:54` is
`height = label:GetStringHeight()` and `AceGUIWidget-CheckBox.lua:90` is
`self:SetHeight(28 + self.desc:GetStringHeight())` — so every Ace options panel on this install
drew its labels and checkbox descriptions at the library's own "avoid zero-height labels" fallback
of one pixel: a window with all of its prose invisible. `addon_harness --probe AI_VoiceOver` builds
that panel's full 32-widget tree with zero errors and every `Label` at `624x1`, which is what
"can't see the actual options in VoiceOver" was.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SgstFWtn1RxEJ5kVrpgYwn
gromandClaude Opus 5
75f04b4f28