Python library for working with SVG paths

Streamlined fork of mathandy/svgpathtools. Focuses on providing complete working support SVG path manipulations without document support. Input/output functionalities are limited to the parsing and pretty-printing of paths.

Main classes:

• Path objects correspond to general SVG paths, made up of one more connected Subpath s
• Subpath objects correspond to continuous (connected) SVG paths; each subpath can be topologically closed or not, and subpaths that are geometrically closed are not necessarily topologically closed (i.e., just because the subpath ends where it starts does not mean that Z property has been set)
• Segment is the parent class of the constituent segments that make up subpaths; each segment is either an Arc or a BezierCurve
• Arc afore-mentioned instance of Segment
• BezierCurve instance of Segment, parent class of Line, QuadraticBezier and CubicBezier
• CubicBezier instance of BezierCurve (and Segment)
• QuadraticBezier instance of BezierCurve (and Segment)
• Line instance of BezierCurve (and Segment)
• Curve base class from which all the above inherit

Thus:

1. a Path is a container of Subpath s
2. a Subpath is a container of Segment s
3. each Segment is either an Arc or a BezierCurve
4. the atomic Segment types are Arc, Line, QuadraticBezier and CubicBezier, with the latter 3 inheriting from BezierCurve
5. besides the inheritances described above, all objects also inherit from Curve, where operations common to all objects such .length or .transform are implemented

Note Path and Subpaths present much the same API and are often interchangeable objects.

Features

• parse and pretty-print paths
• parse and pretty-print SVG transforms, navigating between three format types: transform string, list of tokens (["translate", 0, 10, "scale", 2.3]), and numpy nd.array
• apply transforms to paths
• compute tangent vectors and (right-hand rule) normal vectors
• compute curvature
• compute intersections between paths and/or segments
• compute bounding boxes of paths, subpaths and segments
• reverse segment/subpath/path orientation
• crop and split paths and segments
• offset and stroke paths
• take path unions
• compute enclosed area
• compute arc length
• compute inverse arc length
• convert between path, subpath and segment parameterizations (see notes on Address object below)
• convert Arc segments to CubicBezier segments
• convert Bézier path segments to numpy.poly1d (polynomial) objects
• convert polynomials (in standard form) to their Bézier form
• some HTML color manipulation convenience functions (conversion from rgb tuples to hexadecimal strings and back, named html color table)

The Address object

While positions on paths, subpaths and segments are specified parameterically, this easily leads to "parameter ambiguity". (I.e., does the given real number represent a segment, path or subpath parameter?) To counter the tendency for confusion, the module wraps parameter values inside of a larger Address object that disambiguates the type of the parameter. Address objects can be substituted at all points in the API for parameter values, and the module will check that the right type of Address object is used in the right place.

Prerequisites

• numpy

Licence

This module is under a MIT License.