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3 Commits

Author SHA1 Message Date
Levi Neuwirth 1e054f7109
docs(zoom): the ties both round up, they do not oppose
Review caught the explanation of the 0.015 round-trip break, not the
fix. Three copies of it claimed 16.015 rounds up while 16.005 rounds
down --- "opposite directions". Both round UP.

Verified rather than reasoned about: at the point the quantizer sees
them, 16.015 * 100 is exactly 1601.5 and 16.005 * 100 is exactly
1600.5. Both are exact ties, and half-up sends both away from zero.

So the mechanism is not opposed rounding, it is that half-up is not
symmetric under negation. Rounding up on the way in adds half a
centi-pixel; rounding up on the way out adds another, so the two
errors ACCUMULATE instead of cancelling, and 16.00 -> 16.02 -> 16.01
ends one centi-pixel high. "Opposite directions" would have predicted
them cancelling, which is the reverse of what happens.

Corrected in all three places that carried it: the module comment, the
test's doc comment, and framing section 3.2.

Comments only --- no behavior change, and the witness values in the
tests were already right. Zoom suite still 15/15.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai
2026-08-06 17:50:03 +02:00
Levi Neuwirth 828f57debb
fix(zoom): quantize the step, or the round-trip guarantee is false
THE BOUNDS WERE NOT SUFFICIENT AND THE TEST COULD NOT SEE IT.
`ConfigKind::Number` validates finiteness and bounds and nothing else,
and `on_change` listeners are notified after a value is stored — they
cannot veto. So 0.015 is a perfectly settable step and nothing in the
registry can refuse it.

Used raw it breaks the framed guarantee, because each operation rounds
independently and 16.015 and 16.005 round in OPPOSITE directions:

  step 0.015:  16.00 -> 16.02 -> 16.01     broken
  step 0.37 :  16.00 -> 16.37 -> 16.00     holds

The existing round-trip test used 0.37 — centi-pixel representable — so
it passed against the defect. Bitten now: with the raw value the new
case lands on 16.01, while the 0.37 case still passes, which is exactly
why it needed to be its own witness.

QUANTIZED WHERE USED, not at `set`. Sizes live in integer hundredths
end to end and `validate_font_size` already range-checks the original
and then rounds to the nearest hundredth; rounding the step is that
same operation one level up. A step of 0.015 is not a finer step in
this domain, it is 0.02 written imprecisely.

Enforcing at set time was considered and rejected: the registry cannot
express a precision constraint, and a validating wrapper is bypassed by
a direct `pmacs.config.set` — the seam `autosave` already documents
about its own interval_ms wrapper. Quantizing at the point of use
cannot be bypassed. Both descriptions say "quantized to hundredths", so
`describe-setting` shows it.

The framing header also still said "proposed, awaiting approval" while
the lane and this PR recorded it approved and implemented. Revision 5,
with §3.2 recording the gap and why quantization rather than rejection
closes it.

Verified: fmt, clippy, diff-check, --lib 1900/0, gui_zoom 15/15.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-06 17:24:56 +02:00
Levi Neuwirth aa99ab39d2
feat(zoom): GUI zoom over the font preference that already existed
Ctrl +/- had no effect whatsoever in the GPU frontend. Stage 1 (#219)
fixed what zoom did to the TUI; this is the other half.

NO RENDERING WORK. FontMetrics::scale already derived every GUI
dimension — code size, line height, status band, divider, menu rows,
minibuffer dropdown, gutter advance — and apply_font_facts already
re-metriced all seven buffers in one transaction. This drives the
preference that existed: two settings, three commands, and a restore.

Q#Z1 = (c). Relative zoom needs an origin and the daemon is built never
to know one — font_pref.rs is explicit that it "never learns metrics,
advances, or what resolves". Hardcoding 16.0 would put a pixel constant
on the daemon side; always sending a size would destroy the `None`
state for everyone who never zooms. A configured base is the only
option where the daemon still infers nothing, and the untouched path
stays byte-identical.

THREE THINGS REVIEW CAUGHT THAT REVISION 1 HAD WRONG.

Q#Z3 was not implementable as framed. `keymap_stack::Scope` is
Buffer | Mode | Global and carries no frontend identity, so "bind on
GPU frontends only" does not exist; and FrontendEvent has no
command-invocation variant, so the GPU cannot ask for a command by name
either. A global binding would capture the chord in the TUI and take
away the terminal's own zoom — the very thing the user is pressing it
for. Commands ship; the binding waits on capability-aware keymap
resolution, which is now a named follow-on rather than something
smuggled in here.

The restore seam did not exist. Builtins and init.lua both run BEFORE
install_state_dirs, so a pmacs.state.read at module load returns
nothing, always. saveplace and recentf never meet this because both
read lazily inside functions; zoom must apply with no user action,
which makes it this project's first eager state consumer. Restore lives
at the end of install_state_dirs — by definition the moment state
becomes readable, so it cannot be ordered wrongly and a future third
startup path gets it without knowing it had to ask.

Every size write clobbered the family. set_font replaces both fields
unconditionally, so { size = n } alone silently cleared a configured
family until restart.

BITTEN, THREE WAYS. Dropping family preservation fails 3 tests.
Reverting to the framing's own first parser `^(%d+)$` fails 4 including
the seam restore — it anchors to end-of-subject and rejects the
newline-terminated file the writer emits, which is the contradiction
review caught in the framing before it reached code. Hardcoding the
16.0 origin fails the base test.

Also recorded: a loaded crdt run failed two m6_1 PTY tests with
`stty -a output was: ""`. That is R4/R6's empty-content readiness
family, and it means the readiness-helper audit's scope is wider than
three wait_for_file copies under tests/ — src/process.rs's own tests
carry the shape. Undiagnosed, load-sensitive, green isolated and on a
quiet full run; a scope note for that lane, not a registry row, since
the registry judges red CI runs and these were local.

Verified: fmt, clippy, diff-check, --lib 1900/0, crdt 2085/0,
gui_zoom 13/13, journey 47/0, m4 150/0, gpu 221/0, full_grid 1/1.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-06 16:20:46 +02:00