default_grid_at(point) gives the GridResolution the pencil should snap to,
derived from the meter of the region under the cursor instead of a fixed
quarter. region_default_grid resolves the governing time signature the way the
prepass's resolve_measure_units does (a region measure's, else the score's
first), and time_signature_beat reads its beat — 1/denominator from the display
(4/4 -> quarter, 6/8 -> eighth, 2/2 -> half) — defaulting to a quarter when the
meter has no single denominator or none is declared. None only when the click
resolves to no staff.
This is additive: position_at / insert_note_at still take an explicit
GridResolution, so their signatures and tests are untouched. The GUI's pencil
click (and the empty-staff preview) now pick the grid via
default_grid_at(world).unwrap_or_else(GridResolution::quarter).
Tests: the beat is 1/denominator (4/4, 2/2; mixed-denominator -> none); a
declared 6/8 yields an eighth-note grid; a meter-less score defaults to a
quarter and a non-finite click yields no grid.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NAtEiJtt9yKVV1zjKYmZhS
Levi Neuwirth
7f8d1a1f95