Interface StrokeStyle

§58's StrokeStyle — how a shape's outline is drawn.

const outline: StrokeStyle = {
  width: 0.04,
  paint: { kind: "solid", color: [1, 1, 1, 1] },
  lineJoin: "round",
  dash: [0.2, 0.1],
};
Copy

§58 declares every field as required; this one defaults all but width, following the family's standing rule that a parameter is required exactly when it is the thing — a stroke is its width, and there is no width an engine can invent, while miter/butt/center are the answers SVG, Canvas and §58's own ordering already agree on. The defaults are named on each field and restated in Appendix A terms by expandStroke.

The geometric half is @fourjs/geometry's StrokeGeometryOptions, which this interface re-declares minus its tolerance — a shape has its own Shape2D.tolerance and stroking at a different one than the flattening would put facets on a curve that has none — and plus §58's paint, which the geometry package cannot see because a colour is not geometry.

Validated and copied on assignment (§85): reading gives a fresh record with every optional field resolved, so an in-place edit of the object you passed cannot desynchronise the geometry from the style that produced it — the hazard Polygon.points has to document instead.