svg_path/convex_hull

Convex hull helpers for paths, subpaths, segments, and points.

This module computes closed hulls. Lines, quadratic Beziers, and arcs have semantic hulls: the primitive itself plus the chord joining its endpoints, with tiny/point-like cases collapsed to lines. Cubic Beziers use a cubic-specific support/event solver.

Types

HullError

</>

pub type HullError {
  PathError(svg_path.Error)
  ConsecutiveCurves
  DuplicateAdjacentTValues
  RefinementReachedMaxIterations(Int)
  PurificationReachedMaxIterations(Int)
  LoopUnionCollapsed
  TangentSearchDegenerateLoop
  TangentSearchNonConvexVertex(Int)
  TangentSearchExpectedTwoTangencies(Int)
  SeededWorstDirectionExceededThreshold(Float, Float)
}

Constructors

```
PathError(svg_path.Error)
```
The generated hull segments could not be converted into a valid closed Subpath.
```
ConsecutiveCurves
```
The final hull-piece sequence failed the invariant that curve pieces must be separated by line pieces.
```
DuplicateAdjacentTValues
```
The refined support samples still contained adjacent duplicate segment parameters.
```
RefinementReachedMaxIterations(Int)
```
Support-sample refinement did not settle before the iteration limit.
```
PurificationReachedMaxIterations(Int)
```
Support-sample simplification did not settle before the iteration limit.
```
LoopUnionCollapsed
```
Convex-loop union collapsed to no boundary pieces.
```
TangentSearchDegenerateLoop
```
Tangent search expected a non-degenerate chord polygon.
```
TangentSearchNonConvexVertex(Int)
```
Tangent search found a locally non-convex chord-polygon vertex.
```
TangentSearchExpectedTwoTangencies(Int)
```
Tangent search did not find exactly two tangent transitions.
```
SeededWorstDirectionExceededThreshold(Float, Float)
```
Seeded worst-direction search grew past its allowed interval width.

PointLoopView

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pub type PointLoopView {
  TangentPoint
  OutsidePoint
  InsidePoint
}

Constructors

```
TangentPoint
```
```
OutsidePoint
```
```
InsidePoint
```

Values

path_hull

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pub fn path_hull(
  path: svg_path.Path,
) -> Result(svg_path.Subpath, HullError)

Compute the convex hull of a path.

Move-only subpaths are treated as single points at their starts. The result is a single closed subpath containing the hull of every subpath in the input path.

points_hull

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pub fn points_hull(
  points: List(vec2.Vec2(Float)),
) -> Result(svg_path.Subpath, HullError)

Compute the convex hull of a list of points.

The result is a single closed subpath containing every input point.

segment_hull

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pub fn segment_hull(
  segment: svg_path.Segment,
) -> Result(svg_path.Subpath, HullError)

subpath_hull

</>

pub fn subpath_hull(
  subpath: svg_path.Subpath,
) -> Result(svg_path.Subpath, HullError)

Compute the convex hull of a subpath.

The result is a closed subpath. Move-only subpaths are treated as a single point at their start. Otherwise each individual segment is first converted to its own convex hull, then those convex loops are unioned one at a time.