local path = require'path'

Fast, full-featured 2D geometry library written in Lua.
Includes construction, drawing, measuring, hit testing and editing of 2D paths.

Overview

• modular, bottom-up style programming (procedural, no state, no objects)
• no dynamic allocations on most operations
• all features available under affine transformation, with fast code paths for special cases
• full support for SVG path command set and semantics and more.

Status

See open issues.

Geometric types

• lines, with horizontal and vertical variations
• quadratic bezier curves and cubic bezier curves, with smooth and symmetrical variations
• absolute and relative-to-current-point variations for all commands
• elliptic arcs, 3-point circular arcs and svg-style elliptic arcs and 3-point circles
• composite shapes:
  • rectangles, including round-corner and elliptic-corner variations
  • circles and ellipses, and 3-point circles
  • 1-anchor-point and 2-anchor-point stars, and regular polygons
  • superformula
• catmull-rom splines
• [cubic splines][path2d_spline3] (NYI)
• [spiro curves][path2d_spiro] (NYI, GPL licensed)
• [text][path2d_text], using freetype and native text engines (NYI)

Measuring

• bounding box
• length at time t
• point at time t
• arc length parametrization (NYI)

Hit testing

• shortest distance from point
• inside/outside testing for closed subpaths (NYI)

Drawing

• simplification (decomposing into primitive operations)
• adaptive interpolation of quad and cubic bezier curves
• polygon offseting with different line join and line cap styles (NYI)
• dash generation (NYI)
• text-to-path (NYI)
• conversion to cairo paths for drawing with cairo or with [sg_cairo]
• conversion to OpenVG paths for drawing with the [openvg] API (NYI)

Editing

• adding, removing and updating commands
• splitting of lines, curves and arcs at time t
• joining of lines, curves and arcs (NYI)
• conversion between lines, curves, arcs and composite shapes (NYI).
• direct manipulation [path editor][path2d_editor] with chained updates and constraints, making it easy to customize and extend to support new command types (WIP).

Last updated: 5 years ago | Edit on GitHub