The Shape Builder only used the filled areas of the selected paths, so a
stroke-only line or open path across a shape did nothing. Like the
reference app's Shape Builder, open paths now act as cutting edges:
- pathops::shape_builder: with an open path in the selection, the
regions are the Live Paint planar map's faces (every path an edge), so a
line across a shape splits it and lines can enclose a region of their
own; it also returns each open path cut where other paths meet it. Closed
shapes alone, more than SHAPE_BUILDER_MAX_SEGMENTS segments, or a map
that can't be built fall back to the filled-area arrangement.
- Filled open paths count as closed (an invisible closing edge) where that
encloses an area; unfilled open paths and straight lines stay edges.
- shapeBuilder.merge: merging or deleting regions on both sides of a line
piece removes that piece (the line is split, its other pieces kept); an
area only lines enclose takes the current fill and the front-most
object's look. Alt (erase) within `tolerance` of a line piece deletes it.
Returns `lines` (pieces deleted).
- shapeBuilder.regions also lists the line pieces.
- The tool shares BuilderMap/Touched with the command, highlights the line
piece under the pointer while Alt is held and passes its tolerance.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>