ReadonlycenterHorizontal coordinate of the ellipse's centre.
ReadonlycenterVertical coordinate of the ellipse's centre.
ReadonlydeltaSigned sweep in radians, −2π … 2π. Positive sweeps counter-clockwise in
the Y-up plane (§7a).
ReadonlykindReadonlyradiusSemi-axis along the ellipse's local X axis. Always positive.
ReadonlyradiusSemi-axis along the ellipse's local Y axis. Always positive.
ReadonlyrotationRotation of the ellipse's local axes about its centre, in radians (§7b).
ReadonlystartAngle of the arc's first point, in the ellipse's local frame, in radians.
A circular or elliptical arc (§51 "circular and elliptical arc"), in centre parameterization: the point at angle
θiscentre + R(rotation) · (radiusX·cos θ, radiusY·sin θ).The command stores a signed sweep rather than the end angle the builder was given. Two different
(startAngle, endAngle, counterclockwise)triples can describe the same arc —(0, π)and(0, −π, true)differ,(0, 3π)and(0, π)do not — and a model that kept the raw triple would have to re-derive the sweep in every operation that touches an arc. Path.arc and Path.ellipse normalize once, here, into|deltaAngle| ≤ 2π; reversing an arc negates it, splitting one halves it.When the current point is not the arc's start point, the arc contributes an implicit straight segment to it first — the Canvas rule, and the one that makes a rounded rectangle expressible as alternating lines and arcs.