Multi-line partial extents ("line 1's tail + the first words of line
2") were inexpressible with one-rect-per-drag grips, and the vertical
drags produced sliver rects whose text recompute swept fragments. The
web's re-selection uses what creation already uses: a selection made
during a rect-edge session is intercepted in checkPDFSelectionFor —
rects rebuild from the selection's per-line client rects, text re-reads
via the deduped glyph boxes, saved immediately (grip release-to-save
parity), and the create popover is suppressed for that gesture.
Vertical grip drags clamp to the rect's OWN line box (band ±quarter
height) — multi-line changes go through re-selection, slivers are gone.
Also verifies clean under the duplicated text-layer span sets (the
fork's pdf.js render never clears .textLayer — open bug): the text
recompute dedupes by glyph overlap.
CDP-verified end-to-end: session → multi-line selection → 6-rect
extent + clean text persisted (PUT 200); create popover correctly
suppressed during the session.
John O'Keefe
f69e659d94