Module rsvg::path_builder

Representation of Bézier paths.

Path data can consume a significant amount of memory in complex SVG documents. This module deals with this as follows:

• The path parser pushes commands into a PathBuilder. This is a mutable, temporary storage for path data.

• Then, the PathBuilder gets turned into a long-term, immutable Path that has a more compact representation.

The code tries to reduce work in the allocator, by using a [TinyVec] with space for at least 32 commands on the stack for PathBuilder; most paths in SVGs in the wild have fewer than 32 commands, and larger ones will spill to the heap.

See these blog posts for details and profiles:

• Compact representation for path data
• Reducing slack space and allocator work

Structs

• CubicBezierCurve
  “c” command for paths; describes a cubic Bézier segment.
• EllipticalArc
  “a” command for paths; describes an elliptical arc in terms of its endpoints.
• LargeArc
  Whether an arc’s sweep should be >= 180 degrees, or smaller.
• Path
  An immutable path with a compact representation.
• PathBuilder
  Constructs a path out of commands.
• SubPath
  A slice of commands and coordinates with a single MoveTo at the beginning.
• SubPathCommandsIter
  An iterator over the commands/coordinates of a subpath.
• SubPathIter
  An iterator over the subpaths of a Path.

Enums

• ArcParameterization
  Conversion from endpoint parameterization to center parameterization.
• PackedCommand 🔒
  Packed version of a PathCommand, used in Path.
• PathCommand
  Long-form version of a single path command.
• Sweep
  Angular direction in which an arc is drawn.

Functions

• arc_segment 🔒
  Turns an arc segment into a cubic bezier curve.
• take_one 🔒
• take_two 🔒