A factory for curve generators addressing only lines, but not areas.
Returns a bundle curve factory with the specified beta in the range [0, 1], representing the bundle strength. If beta equals zero, a straight line between the first and last point is produced; if beta equals one, a standard basis spline is produced.
A constant value in the [0, 1] interval.
A curve factory for straightened cubic basis spline generators.
The curve generators produce a straightened cubic basis spline using the specified control points, with the spline straightened according to the curve’s beta, which defaults to 0.85. This curve is typically used in hierarchical edge bundling to disambiguate connections, as proposed by Danny Holten in Hierarchical Edge Bundles: Visualization of Adjacency Relations in Hierarchical Data.
This curve does not implement curve.areaStart and curve.areaEnd; it is intended to work with d3.line, not d3.area.