@oh-just-another/math

Pure 2D geometry — vectors, matrices, bounds, color, intersection.

L0 geometry kernel. Pure functions, no DOM, no Node API, no runtime dependencies. Modules are exported as namespaces:

import { vec2, matrix, bounds, hitTest, bezier, intersect, color } from "@oh-just-another/math";

const m = matrix.multiply(matrix.translation(10, 20), matrix.rotation(Math.PI / 4));
const p = matrix.applyToPoint(m, { x: 1, y: 0 });
const b = bounds.fromPoints([p, { x: 100, y: 50 }]);

Modules

| Module | What's inside | | ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------- | | vec2 | add/sub/mul/div/negate, dot, cross, length(Sq), distance(Sq), normalize, lerp, angle, rotate, perp, equals (with epsilon). | | matrix | IDENTITY, translation / scaling / rotation, multiply, inverse, applyToPoint, applyToBounds, decompose (TRS), equals. | | bounds | EMPTY, of, fromPoints, fromCenter, centerOf, maxX/maxY, isEmpty, union, intersection(/intersects), contains(Bounds), expand, normalize, equals. | | hitTest | pointInRect, pointInPolygon (even-odd ray casting), distanceToSegment(Sq), pointOnSegment, pointOnPolyline. | | bezier | quadraticAt / cubicAt, quadraticBounds / cubicBounds (via extrema), pointOnQuadratic / pointOnCubic, flatten helpers. | | intersect | lineLine, segmentSegment, segmentQuadratic (algebraic), segmentCubic (sampled). | | color | parse / format / mix / withAlpha; supports #rgb, #rgba, #rrggbb, #rrggbbaa, rgb(), rgba(), named subset. |

Re-exports RGBA and DecomposedTransform types from the relevant modules.

Conventions

• All functions are pure — they never mutate inputs.
• Vec2, Bounds, Transform are immutable by convention (no readonly enforcement at runtime).
• Epsilon parameters default to 0 (strict). Use a positive epsilon for floating-point tolerance.
• The pointOn* Bezier helpers and segmentCubic are sampled approximations suited for interactive picking; pixel-precise rendering belongs to the renderer packages.