@truedxf/geometry

Fast float64 CAD geometry: NURBS, arcs, ellipses, OCS, dashing, hatching, stroking and clipping, tuned to AutoCAD's output.

The float64 geometry kernel of truedxf, with no dependency on the DXF model.

Install

pnpm add @truedxf/geometry

ESM only. No DOM and no Node.js APIs: runs in browsers, workers and Node.

What it does

• Vectors as plain { x, y } / { x, y, z } objects (Vec2, Vec3, add3, cross3, ...), so model points pass in without conversion, plus Matrix44, Affine2, Bounds2, Bounds3.
• OCS: arbitraryAxis, ocsToWcsMatrix, wcsToOcsMatrix (arbitrary axis algorithm, 1/64 threshold) and entityCoordinateSystem / isOcsPoint, which say per entity type and group code whether a point is OCS or WCS.
• Curves: bulge arcs (bulgeToArc, arcToBulge), elliptic arcs (ellipseFromDxf, ellipseParamToAngle), NurbsCurve with Bezier extraction, buildSplineCurve for DXF SPLINE data and interpolateFitPoints for fit-point-only splines (AutoCAD's construction, note 03 §3.8.6). Exact bounds for every segment type.
• Paths of line, arc, elliptic-arc, quadratic, cubic and NURBS segments (Path2, PathBuilder, transformPath, projectCurve3), flattened by flattenPath with a device-space chord tolerance (default 0.1 px) and deterministic, capped segment counts.
• Polylines: bulgePolylineToSubpath, widePolylineOutline (tapered widths, AutoCAD's miter and arc-width rules, note 03 §4), curve-fit and spline-fit vertex selection.
• strokePolyline / strokeOutline: width, butt/square/round/diamond caps, miter/bevel/round/ diamond joins, miter limit.
• Linetypes: dashPolyline / dashPath with pluggable dash fitting (autocadCandidateFit, phaseFit), dots, and placements of complex shape/text elements.
• Hatches: loop selection by hatch style (selectHatchLoops), solid fill (hatchSolidTriangles), clipped pattern lines (hatchPatternLines, 100 000-line limit).
• Booleans and clipping via clipper2 on a fixed-point grid derived from the tolerance (booleanPolygons, clipPolygons, clipPolylines), exact clipPolylineToRect, and triangulateFill (clipper2 union + earcut) for even-odd and non-zero fills.
• No DOM and no node:* imports: runs in browsers and Node. No randomness, no time limits.

Usage

import {
  Affine2, bulgePolylineToSubpath, dashPattern, dashPolyline, flattenSubpath, strokePolyline,
  transformSubpath,
} from "@truedxf/geometry";

// LWPOLYLINE vertices (OCS): a 10 x 5 slot, bulge 1 = half circle
const centre = bulgePolylineToSubpath(
  [{ x: 0, y: 0 }, { x: 10, y: 0, bulge: 1 }, { x: 10, y: 5 }, { x: 0, y: 5, bulge: 1 }],
  true,
);

// to device pixels first, then flatten with 0.1 px max sagitta
const px = flattenSubpath(transformSubpath(centre, Affine2.scaling(20)), 0.1);

const triangles = strokePolyline(px.points, { width: 3, closed: true, join: "round" });
const dashed = dashPolyline(px.points, dashPattern([0.5, -0.25], 20), { closed: true });
console.log(triangles.length / 6, "triangles,", dashed.dashes.length, "dashes");

License

MIT. AutoCAD and DXF are trademarks of Autodesk, Inc. truedxf is not affiliated with or endorsed by Autodesk.