The grid now zooms, which needs thumbnails at two resolutions rather than
one, and exposed a scrub that landed in the wrong place.
**Two thumbnail size classes.** `ThumbSize::Grid` (256px, ~10 KB) and
`Large` (1024px, ~45 KB), with the class part of the store key so both
coexist. Storing everything large would take the reference library from
~200 MB to ~860 MB, and shards sync, so that is transfer cost on every
device rather than only disk. A store written before the class existed
migrates in place: its entries are all grid-sized, which is what the
column defaults to, so nothing already fetched is discarded.
`forget` now drops every size for an image. Reading a single row left the
other class's bytes on the shard's tally for good, sealing it early on
space nothing occupied.
**Grid zoom.** Ctrl+wheel and pinch resize cells between 90px and 420px in
geometric steps, so the gesture feels the same at either end where a fixed
pixel step would be imperceptible at 400px and violent at 90px. Crossing
256px switches to the large class, so a zoomed cell is sharp rather than
upscaled. Columns and window capacity already derived from cell size, so
the grid reflows for free.
**The scrub landed about half a library too high.** It counted only dated
images while the grid shows all of them — 10,733 dated against 19,841
rows — and ignored `shadowed_by`. Verified against the live catalog: the
old formula gave 10,887, the new one 10,732, the true grid position
10,732. The scrub's count and the grid's window must use identical
predicates and ordering; a test now fails if they diverge.
**Timeline gestures are continuous.** Scrub and pan were quantised to
whole buckets, so a slow drag did nothing until it crossed a boundary and
then jumped a month. Both work in fractions of the visible span now, and
pinch-to-zoom arrives for tablet, where there is no wheel to reach the
axis with.
The pinch accumulator was wrong on first writing: it took at most one step
per update, so an 8x spread — three doublings — yielded one zoom level.
`log2().trunc()` now extracts every whole doubling and carries the
remainder. The original test asserted the wrong number and defended it in
a comment, which is worth remembering: a test can entrench a bug as
readily as catch one.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
A thumbnail is the one derived artefact worth sending over the wire: it costs
a range fetch plus a decode to produce and is identical for every client
looking at the same file. A second device that downloads a shard gets a full
grid without fetching a byte of RAW.
Sharded at 25 MB, filled sequentially. The cap is about sync granularity, not
SQLite's limits — one growing database means every client re-downloads it
whenever a single thumbnail is added, whereas with sequential fill only the
newest shard is ever dirty and sealed shards are safe to cache forever.
Stored JPEG-encoded rather than as raw RGBA: a 256px RGBA buffer is ~256 KB
against ~20 KB encoded, and that 13x is transfer cost on every client.
Keyed on Nextcloud's oc:fileid, stable across server-side rename and move.
Assisted-by: LLM
dtourolleandClaude Opus 5