editor

ADR-0006 — Non-destructive boolean operations ​

Status: Accepted

Context ​

The user draws with integers only. A boolean operation creates vertices at intersections, usually non-integer. Storing them would destroy the "everything is integer, everything is editable" philosophy.

Decision ​

  • A boolean operation creates a boolean node in the tree: { operation, operands[] }.
  • The operands are kept intact (integers, radii included) and stay editable.
  • The result is evaluated at each render (stage 3, ADR-0005). Its non-integer vertices only exist in the derived geometry.
  • The operands' corner radius is applied before the operation: the operation works on segments + arcs.
  • Shape Builder-like tool (Inkscape 1.3): non-destructive version. A selected region is stored as a combination "inside A, outside B…", not as an outline.
  • No destructive flatten command in v1. Introducing one will require an ADR + a rounding rule (REF-HOBBY-1999).

Consequences ​

  • The model stays 100% integer.
  • Boolean computation must handle segment/segment, segment/arc, arc/arc.
  • Corner radius on the new vertices of a result: not available in v1 (Q9).

References ​

REF-INKSCAPE-BOOL, REF-INKSCAPE-SHAPEBUILDER, REF-MARTINEZ-2009