Documentation
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Overview ¶
The heap contains every point in the polygon Popping the heap will give you the point with the smallest angle/area a.k.a: the least significant point
helper package for determining if edges cross
Concrete implementation of VertexCollection for traversing "lines"
Concrete implementation of VertexCollection for traversing "loops"
Index ¶
- func BuildRTreeRect(points ...s2.Point) (*rtreego.Rect, error)
- func CreatesIntersection(rtree *rtreego.Rtree, point *PointWithTriangle) []s2.Edge
- func EdgesCross(a, b s2.Edge) bool
- func PolylineSelfIntersects(polyline s2.Polyline) ([]s2.Edge, error)
- func TriangleArea(point *PointWithTriangle) float64
- func TriangleBbox(point *PointWithTriangle) (*rtreego.Rect, error)
- func Visvalingam(pointList VertexCollection, threshold float64, minPointsToKeep int, ...) (err error)
- type PointWithTriangle
- type PointWithTriangleHeap
- type PointWithTriangleList
- func (l *PointWithTriangleList) Do(f func(*PointWithTriangle) error) error
- func (l PointWithTriangleList) Len() int
- func (l *PointWithTriangleList) Next(point *PointWithTriangle) *PointWithTriangle
- func (l *PointWithTriangleList) Prev(point *PointWithTriangle) *PointWithTriangle
- func (l *PointWithTriangleList) PushBack(e *PointWithTriangle)
- func (l *PointWithTriangleList) Remove(e *PointWithTriangle)
- type PointWithTriangleRing
- func (r PointWithTriangleRing) Do(f func(*PointWithTriangle) error) error
- func (r PointWithTriangleRing) Len() int
- func (r PointWithTriangleRing) Next(point *PointWithTriangle) *PointWithTriangle
- func (r PointWithTriangleRing) Prev(point *PointWithTriangle) *PointWithTriangle
- func (r *PointWithTriangleRing) PushBack(e *PointWithTriangle)
- func (r *PointWithTriangleRing) Remove(e *PointWithTriangle)
- type VertexCollection
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func CreatesIntersection ¶
func CreatesIntersection( rtree *rtreego.Rtree, point *PointWithTriangle, ) []s2.Edge
returns the first intersection it finds when removing `point` given the triangle abc, see if the vector ac intersects with the remainder of the linked list
func EdgesCross ¶
Factored out because of repeated confusion around correct fn to use H.C: while `EdgeOrVertexCrossing` may look tantilizing do _not_ use it it will identify two lines that share a vertex as crossing
func PolylineSelfIntersects ¶
This method provided exclusively for testing uses a more straightforward but slower approach, helpful when debugging
using an rtree for efficient(ish) lookup identify if a polyline self intersects
"R-trees are balanced, so maximum tree height is guaranteed to be logarithmic in the number of entries; however, good worst-case performance is not guaranteed. Instead, a number of rebalancing heuristics are applied that perform well in practice."
func TriangleArea ¶
func TriangleArea(point *PointWithTriangle) float64
func TriangleBbox ¶
func TriangleBbox(point *PointWithTriangle) (*rtreego.Rect, error)
func Visvalingam ¶
func Visvalingam( pointList VertexCollection, threshold float64, minPointsToKeep int, avoidIntersections bool, ) (err error)
Types ¶
type PointWithTriangle ¶
type PointWithTriangle struct {
Point s2.Point
// The area this triangle occupies with
// the triangle (point-1)(point)(point+1)
Area float64
HeapIndex int
// the bounding box of the triangle formed
BBox *rtreego.Rect
// contains filtered or unexported fields
}
func NewPointWithTriangle ¶
func NewPointWithTriangle(point s2.Point) *PointWithTriangle
func (PointWithTriangle) Bounds ¶
func (p PointWithTriangle) Bounds() *rtreego.Rect
func (*PointWithTriangle) Next ¶
func (p *PointWithTriangle) Next() *PointWithTriangle
Defer to the list for next behaviour
func (*PointWithTriangle) Prev ¶
func (p *PointWithTriangle) Prev() *PointWithTriangle
type PointWithTriangleHeap ¶
type PointWithTriangleHeap struct {
// contains filtered or unexported fields
}
func (PointWithTriangleHeap) Len ¶
func (h PointWithTriangleHeap) Len() int
func (PointWithTriangleHeap) Less ¶
func (h PointWithTriangleHeap) Less(i, j int) bool
Our heap is sorted by area
func (*PointWithTriangleHeap) Pop ¶
func (heap *PointWithTriangleHeap) Pop() (tailI interface{})
func (*PointWithTriangleHeap) Push ¶
func (heap *PointWithTriangleHeap) Push(value interface{})
func (PointWithTriangleHeap) Swap ¶
func (h PointWithTriangleHeap) Swap(i, j int)
type PointWithTriangleList ¶
type PointWithTriangleList struct {
// contains filtered or unexported fields
}
func NewPointWithTriangleList ¶
func NewPointWithTriangleList() *PointWithTriangleList
func (*PointWithTriangleList) Do ¶
func (l *PointWithTriangleList) Do(f func(*PointWithTriangle) error) error
func (PointWithTriangleList) Len ¶
func (l PointWithTriangleList) Len() int
func (*PointWithTriangleList) Next ¶
func (l *PointWithTriangleList) Next(point *PointWithTriangle) *PointWithTriangle
func (*PointWithTriangleList) Prev ¶
func (l *PointWithTriangleList) Prev(point *PointWithTriangle) *PointWithTriangle
func (*PointWithTriangleList) PushBack ¶
func (l *PointWithTriangleList) PushBack(e *PointWithTriangle)
func (*PointWithTriangleList) Remove ¶
func (l *PointWithTriangleList) Remove(e *PointWithTriangle)
type PointWithTriangleRing ¶
type PointWithTriangleRing struct {
// contains filtered or unexported fields
}
func NewPointWithTriangleRing ¶
func NewPointWithTriangleRing(root *PointWithTriangle) *PointWithTriangleRing
func (PointWithTriangleRing) Do ¶
func (r PointWithTriangleRing) Do(f func(*PointWithTriangle) error) error
func (PointWithTriangleRing) Len ¶
func (r PointWithTriangleRing) Len() int
func (PointWithTriangleRing) Next ¶
func (r PointWithTriangleRing) Next(point *PointWithTriangle) *PointWithTriangle
func (PointWithTriangleRing) Prev ¶
func (r PointWithTriangleRing) Prev(point *PointWithTriangle) *PointWithTriangle
func (*PointWithTriangleRing) PushBack ¶
func (r *PointWithTriangleRing) PushBack(e *PointWithTriangle)
func (*PointWithTriangleRing) Remove ¶
func (r *PointWithTriangleRing) Remove(e *PointWithTriangle)
type VertexCollection ¶
type VertexCollection interface {
Remove(*PointWithTriangle)
Len() int
Do(f func(*PointWithTriangle) error) error
Prev(p *PointWithTriangle) *PointWithTriangle
Next(p *PointWithTriangle) *PointWithTriangle
}
Interface for traversing our shape that we can implement in ring & non-ring ways please see pointlist.go and pointring.go for concrete implementations
Source Files