The port of the block Slint repeats in 27 views (NavState.restore-scope /
scroll-restore / report-scroll). A .slint file cannot hand a component a
reference to a Flickable, which is why the reference inlines it; QML can, so
controls/ScrollMemory.qml exists once and 31 containers mount it.
Two divergences from the reference, both forced by the same fact — tabs are not
history entries in this port:
1. THE SCOPE IS NAMED BY THE VIEW, not derived from the entry by a scope_for
table. Slint can derive it because its entries carry the tab
(Favorites { tab }); here an entry is a bare route id, so a derived scope
would read "library" for all five Library tabs and pour the Albums grid's
offset into whatever tab mounted. Letting the reporter name its own scope
buys tab granularity for free, and the mismatch case degrades the right way:
an unmatched scope restores NOTHING instead of restoring the wrong thing.
2. THE RESTORE RE-ASSERTS instead of firing once. A Qt item view resets
contentY to 0 whenever its model is replaced, and several pages assign their
model from a binding whose inputs arrive over the network after the mount —
the album page rebuilds listCells from three deferred rails, so it hands its
ListView a new array up to four times in its first seconds and snaps back to
the top over a restore that already ran correctly. The offset is held and
re-applied until a 2.5 s deadline, or until the user takes over (a wheel, a
drag or a flick raises `moving`, and from then the position is theirs).
Diagnostics are off by default: QT_LOGGING_RULES="qbz.nav.scroll.info=true" for
the QML half, RUST_LOG=qbz=debug for the stamp/arm half.
cc
AppShell hides its BezelCorner nubs while the field is meant to show
through the pane's corners, and Qt's clip is a rectangular scissor that
ignores radius — so any full-bleed child at y=0 squares the pane. The
doctrine was already written in AppShell.qml ("a full-bleed pane child
must round itself; there is no mask that can do it for it here"); these
eight surfaces predated it or, in the two thin bars added with the
ambient port, ignored it.
- The seven fixed 56px headers (Home, Search, DiscoverBrowse,
ArtistReleases, PlaylistBrowse, PlaylistManager, PlayHistory) take
topLeftRadius/topRightRadius. Invisible with the background off, where
the view root paints the same colour beneath. PlaylistBrowse's SECOND
bar is the category strip at mid-page and keeps square corners;
PlayHistory keeps its unconditional opaque fill, which is reference
parity (:43/:34) and a separate question from the corner.
- LocalAlbumView's neutral header band is now gated on the background,
1:1 with the Qobuz page's atmosphere (AlbumView headerAtmoOn,
AlbumPageView.slint:168): the two dark backdrops clash and the field
already provides one. That band had been square since it was written;
the nubs had been hiding it, and they only stand down when the field
is showing. Header text there is theme.textPrimary, not the Qobuz
page's light-on-dark hdrStrong, so it does not depend on the band to
stay readable — checked before removing the backdrop from under it.
Gate: cargo build -p qbz-qt, both QML audits, offscreen smoke 0
complaints.
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Accumulated qt-frontend work from the 2026-08-11/12 sessions (cc),
uncommitted until now: the app-wide dynamic background in both modes
(AmbientField with GPU/Canvas arms, AppShell layering, ambient palette
pipeline), the wave-1 clip/batch sweep across the tree (alpha batches
449 -> 327, reproducible), the rounded-cover and icon-tint arms, and
scripts/qt-batches.sh (batches + presents/s sampler).
The GPU behaviour of these pieces was finalized in the follow-up pulse
commits; see qbz-nix-docs/qt-frontend/2026-08-11-scenegraph-batches/
GPU-COST-INVESTIGATION.md for the full campaign.
km
The release-section "Load more" fetched a page and appended it to a structure
no view ever re-read. The handler pushed IN PLACE into the object behind
`readonly property var artist: JSON.parse(QbzArtist.artistJson)`, and the
releaseSections projection returned that same array on the unfiltered arm, so
both Repeaters were re-handed the identical reference and nothing was dirty.
The tree's own rule, written in cards/PlaylistCollage.qml: rebind requires a
NEW object reference. A second bug sat on the same path - the artist document
republishes progressively (stories, then each MusicBrainz section as it
resolves) and every republish re-runs the parse, wiping anything appended, so
fixing only the first would have left a bug that looks random. Both
pre-existing; the in-flight placeholder added earlier is what made an
always-silent no-op visible.
Appended pages now live in an overlay keyed by release type. It survives a
republish, emits new arrays so the Repeaters rebuild, dedupes by album id,
carries the reference's 4-page cap per bucket (artist.rs:718-720, which hands
off to the discography page beyond it), and is guarded against a page
requested on one artist landing on another's grid - releaseSectionReady
carries no artist id and every artist has an "album" bucket.
"See discography" was a pointer-cursor MouseArea with no onClicked under a
POC-NOTE saying the page was out of scope. ArtistReleasesView.qml +
artist_releases_qt.rs port ArtistReleasesView.slint: infinite scroll rather
than a button, plus the loading, error-with-retry, empty and offline arms.
The album page's "More from <artist>" view-all is a second door to the same
page. Its paging offset counts what the SERVER returned rather than the
rendered row count the reference uses: blacklist filtering and id dedupe make
the rendered count smaller, so the reference re-requests seen rows and skips
the tail whenever the blacklist is non-empty.
The per-section sort was a dimmed Rectangle with no MouseArea, under a
comment asserting no seam existed. It is now a real QbzSelect with the
reference's five options and index mapping, persisted per release type in
artist_prefs. Choosing "Default" after a sort does not restore the server
order until the page reloads - that is the reference's behaviour
(album_map.rs:262 is a bare no-op arm and resort sorts the live model), kept
deliberately rather than diverged.
Also, two visual fixes from the same round that share these files: Popular
Tracks drew its cover at radius 8 where the shared rows/TrackRow.qml uses 4,
and the album page's rail mounts said `width: parent.width` inside a Column
with 32px padding - QML padding shifts children without narrowing
parent.width, so the rails hung 32px off the right and the right page chevron
landed outside the window.
Carries scripts/qt-diag.sh, which has been sitting untracked since the
rendering round: it answers "which backend is this actually running on" from
a real graphical session, refusing ssh and refusing offscreen because either
would answer the wrong question. That refusal is the point - the doctrine it
disproved ("shader effects render nothing on this port's software path") came
from an offscreen observation, and offscreen forces software by definition.
cc
vicrodh