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.
Read the autofocus point from Sony maker notes (FocusLocation 0x2027, FocusFrameSize
0x2037, FocusMode 0x201b, AFAreaModeSetting 0x201c, AFTracking 0x2021 and the area mode
used from the enciphered 0x9402 block), for the ILCE-1 and ILCE-7SM3, whose layout was
checked against ExifTool's output on 333 real ARWs. Manual focus, centre-only Multi
reports and unchecked bodies give no point. The box is stored on the upright photo as
Meta.focus (omitted when unknown; no catalog format change), filled at import and by
Reload from Disk.
View > Show Focus Point (Alt+F) draws it in Detail, Compare and Survey through rotation
and crop; View > Zoom to Focus Point (on by default) makes Toggle Zoom centre on it; the
Info panel shows "AF-C · Wide · Animal Eye Tracking". photo.inspect returns meta.focus.
Jason Baldwin