FR-DEV-3 has asked for "white balance (temperature/tint, and picker)" since
it was written, and only the first half existed. `WidgetKind::WhitePoint` was
in the vocabulary and `develop::supported` answered false for it, so the node
degraded to two sliders — correct behaviour that had quietly become the only
behaviour. Sampling a neutral is the first move of the global tonal pass and
every colour judgement afterwards is measured against where the grey was put,
so guessing at two sliders until a wall stops looking green is the wrong way
round.
The awkward part is that a picker genuinely needs to know how far a hundred
units of temperature move red against blue, and that number is declared in
the node's own file. So the inversion lives in `dr_pipeline::neutral` rather
than in the interface: the canvas hands over a colour, the core finds the
operation that asked to be driven by a pixel and bisects its declared
response until the sample comes back grey. Nothing in `ui/` names white
balance, and nothing holds a second copy of a response that would be wrong
the first time somebody adjusted the range. A bisection rather than a
closed-form inverse because only monotonicity is part of the bargain — the
expression is free to become a table tomorrow.
The result is rounded to the precision the control is drawn at, which is not
cosmetic: unrounded, sampling something already neutral lands a
ten-thousandth off zero, and the photograph comes back modified with an undo
step for a correction of nothing.
On the panel side this needed one distinction the generated path was
missing. `is_on_canvas` was being read as "and so the panel draws nothing for
it", which is right for a crop — four edge fractions are not controls anyone
drags in a list — and wrong for an eyedropper, which *writes* temperature and
tint and leaves them exactly the controls a photographer reaches for next.
So a sampling widget keeps its sliders and puts the affordance that arms the
canvas in the group's heading, built like the reset beside it. One click, one
sample, one history step: `Edit::Action` never coalesces, and there is no
hover preview to fill the stack with temperatures nobody chose.
Declaring the presentation also groups temperature and tint under one undo
step, where they were two. That follows from what `Presentation` means and
reads correctly — white balance is one decision — but it is a change, and
worth saying so.
Tool tabs need a taxonomy, and the taxonomy was the problem: a table in
`ui/` mapping operation to tab breaks FR-DEV-3a, and a `group:` field risks
what `ui-refinement.md` condemned `starts-group` for — the core deciding
where the panel draws things.
`Attribute` threads the needle. It says what an operation *is* — tone,
colour, detail, optics, geometry, effect — which is the same category as
`ParamKind` and squarely on the core's side of ARCH §4.3a's line. What is
drawn, where it sits and whether it is visible stay the frontend's. There is
no attribute for "the third tab", the enum's order is declaration order
rather than screen order, and a frontend may render these as tabs, as
headings, or ignore them.
The payoff is that a tab strip can be *derived*: the groups are the
attributes present in the capability list, so the interface names no
operation and needs no table to keep in step. An operation joins the right
group by declaring what it is, which is the one thing its author is well
placed to say.
Plural, because the tone curve is genuinely both — an RGB curve is tonal and
the per-channel curves are chromatic, and filing it under one would hide it
from half the people looking for it.
Required and non-empty, enforced in `build.rs`, and the failure was checked
by removing the line rather than assumed. An operation with no attribute is
invisible to a panel that groups by them; a build that stops costs ten
seconds, a control nobody can find costs more. The vocabulary is closed for
the same reason: a typo would otherwise invent a category holding exactly one
operation, which looks like a deliberate one until somebody counts.
Six tests over the real chain, including the hand-written operations that
`build.rs` never sees and so cannot check.
Every background job reported into a window property of its own —
library-thumbs-done, library-pin-total, library-syncing — which only the
grid ever read. A pin download that outlived the view it was started from
drew nothing at all once the user opened an image, and there was no answer
anywhere to "what is this busy with", because the answer was spread across
eight properties nothing collected.
They report to one register now (ui/dr-ui/src/activity.rs). It publishes an
aggregate, which draws a three-pixel bar across the top of the shell in
every view, and a row per job, which the settings page lists: scans,
thumbnail batches, pin and open downloads, sidecar uploads, the sync and
the trash. Failures stay on the list until they are cleared; routine
successes do not, or a scroll would bury them.
The handle removes a still-running job when it drops, so a worker that dies
mid-transfer takes its row with it rather than leaving the bar sweeping for
the rest of the session.
Also carries in-flight work from a parallel session — the drawn icon set
and the dr-pipeline ops split. dr-pipeline's build script does not compile
at this commit; ui/dr-ui does, with clippy clean and its tests passing.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
dtourolle
