Geometry Primitives

This package provides essential geometric primitives and utilities for 2D graphics and spatial calculations in Mural applications.

Available Primitives

Point

A basic interface representing a point or vector in 2D space with x and y coordinates.

For points we use POJO like { x: 0, y: 0 } to make it easy to serialize/deserialize it. Use namespace syntax to access points methods (Point.add(p1, { x: dx, y: dy })).

Other geometry primitives like Aabb and Obb are regular JS classes.

import { Point } from '@muralco/geometry';

// Example usage
const { add, scale, fromSize } = Point;
const center = add(leftTop, scale(fromSize(size), 0.5));

The Point namespace provides numerous utility functions for vector operations, including:

• Vector arithmetic (add, sub, mul, etc.)
• Normalization and scaling
• Distance and length calculations

Matrix

A 2D transformation matrix for representing and combining translations, rotations, and scaling.

import { Matrix } from '@muralco/geometry';

// Rotation around a specific point
const matrix = Matrix.identity()
  .translate(Point.neg(origin))
  .rotate(angleInRadians)
  .translate(origin);

const transformedPoint = matrix.transform(myPoint);

Aabb (Axis-Aligned Bounding Box)

A rectangle defined by minimum and maximum X/Y coordinates, always aligned to the coordinate axes.

import { Aabb } from '@muralco/geometry';

// Create from points
const bounds = Aabb.fromPoints([point1, point2, point3]);

// Check if a point is inside
if (bounds.includesPoint(somePoint)) {
  // Point is inside the bounding box
}

Obb (Oriented Bounding Box)

A rectangle with arbitrary orientation, defined by a size and a transformation matrix.

import { Obb } from '@muralco/geometry';

// Create an OBB
const obb = new Obb(
  { width: 100, height: 50 },
  Matrix.rotation(Math.PI / 4) // 45 degrees rotation
);

// Map points between spaces
const globalPoint = obb.mapToGlobal(localPoint);

Angles (Radians/Degrees)

There are two angle representations in this package: Radians and Degrees. Both are tagged types to not confuse them with regular numbers, or use with incorrect units.

import { Radians, Degrees } from '@muralco/geometry';

// Create a Radians value from a regular number
const r: Radians = Radians(Math.PI / 2);

// Create a Degrees value from a regular number
const d: Degrees = Degrees(90);

// Convert between radians and degrees
const radians1: Radians = Radians.fromDegrees(90);
const degrees1: Degrees = Radians.toDegrees(radians1);

const degrees2 = Degrees(45); // Just add the `Degrees` tag to a number
const radians2 = Degrees.toRadians(degrees2);

// Normalize to [0, 2π)
const normalizedRadians = Radians.normalize(radians1);

// Normalize to [0, 360)
const normalizedDegrees = Degrees.normalize(degrees1);