`write_note` built the icon rectangle as `[y, x, y + 20, x + 16]` with plain
i32 arithmetic on a position that comes straight from the file's `Anno`
block (or from `notes.set`). A stored icon top at or above `i32::MAX - 19`
overflowed on every PSD save, because `export_blocks` regenerates the
comparison block before deciding whether the stored one can be kept
verbatim: a panic in debug (surfaced by `file.saveACopy` as an internal
error, no file written), a wrapped bottom edge in release.
The far edge now uses `saturating_add`, matching the cast that already
saturates the origin, so the written rectangle is always representable and
the note survives a round trip at its stored position. No signature change:
`write_note` stays infallible and unchanged notes still compare byte-exact.
Test: `a_note_icon_near_i32_max_saves_with_representable_geometry` builds
the issue's `Anno` fixture at `i32::MAX - 5` (and a far-left and
`i32::MIN` variant), imports, exports, checks the written icon rectangle
and re-imports; also covers a model position beyond i32 and NaN, and the
ordinary `[42, 28]` control. Panicked at `annotations_map.rs:183` on main.
Co-authored-by: wstock <1394687+wstock@users.noreply.github.com>
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
MarekSpodBiedry