Photos imported before focus points were read got one only through Reload from Disk, which
hashes whole files on the UI thread. Now:
- lightcraft_meta::focus::read_header reads only what the decoder looks at: IFD0 (Make,
Model), the Exif IFD, the maker note's IFD and the focus tags' values (a JPEG: its segments
up to the Exif one), walked round by round and decoded with the whole-file code from a
buffer of the file's length holding just those ranges. Bounded rounds, bytes (2 MB) and
size (1 GB). One 32 KB read per α1 / A7S III ARW; on 109 real files (83 with a point)
it gives the whole-file read's point for every one.
- A background job (crates/engine/src/focus_scan.rs) reads photos with no point from a
supported body (by the stored camera; nothing else is opened), ARW or JPEG, one at a
time in path order, with a "Reading focus points" activity row (Cancel::Flag). The UI's
per-frame focus.pump gives it the face scan's pace (paused while dragging or typing) and
starts it once per library opening. Commits every 200 photos or 3 s as system ops (no
undo step, no sidecar write), only meta.focus, only on photos that still have none at the
same path. "Looked, none" goes to focus-scanned.bin beside the library, headed by the
decoder's tag so a decoder knowing more bodies starts afresh; unreadable files are retried
at the next opening.
- photo.readFocusPoints {ids?, wait?} (Photo > Read Focus Points) runs it on demand.
Measured cold on a 5400 rpm USB drive: 200 α1 / A7S III ARWs in 1.9 s (~100 photos/s,
32 KB each), so 58,796 raws take about 10 minutes instead of re-reading 2.25 TB.
A raw's embedded JPEG, a thumbnail, the previous render after an edit or the magnified
frame under a 1:1 window all look like the finished photo. Once a render has been on its
way for 0.5 s with nothing new on screen, a pill at the bottom of the photo (widget
`loupe:rendering`) says so; above the Navigator when that is in the way.
The wait starts when the render starts coming (an idle app draws no frames), so a quick
render never shows it, nor does a drag whose drafts keep up; once up it stays until
nothing is coming, so slow drafts don't make it blink. It watches what is on screen: the
After or the Before, and the windows in use. Not an activity row: it says the pixels
aren't final (docs/background-tasks.md).
Co-Authored-By: Claude <noreply@anthropic.com>
CLAUDE.md gains the rule (a TaskGuard for every job that runs off the UI
thread and can take more than a moment; no progress window, panel or
toast of its own), and docs/background-tasks.md says how: kind, label,
progress, units, detail, the three ways to cancel, examples and tests.
Photo Merge's and the face scan's docs no longer describe the old
progress toast.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Jason Baldwin