Class S2ShapeUtil.S2EdgeVectorShape

java.lang.Object
java.util.AbstractCollection<S2Edge>
java.util.AbstractList<S2Edge>
com.google.common.geometry.S2ShapeUtil.S2EdgeVectorShape
All Implemented Interfaces:
S2Shape, Iterable<S2Edge>, Collection<S2Edge>, List<S2Edge>, SequencedCollection<S2Edge>
Enclosing class:
S2ShapeUtil

static class S2ShapeUtil.S2EdgeVectorShape extends AbstractList<S2Edge> implements S2Shape
S2EdgeVectorShape is an S2Shape representing a set of unrelated edges. It contains no area and has no interior. Although it implements List, only the add(S2Point, S2Point) method can mutate the list of edges.

It is mainly used for testing, but it can also be useful if you have, say, a collection of polylines and don't care about memory efficiency (since this class would store most of the vertices twice.) If the vertices are already stored somewhere else, you would be better off writing your own subclass of S2Shape that points to the existing vertex data rather than copying it.

  • Field Details

  • Constructor Details

    • S2EdgeVectorShape

      public S2EdgeVectorShape()
      Default constructor creates a vector with no edges.
    • S2EdgeVectorShape

      public S2EdgeVectorShape(S2Point a, S2Point b)
      Convenience constructor for creating a vector of length 1.
  • Method Details

    • add

      public void add(S2Point a, S2Point b)
      Adds an edge to the vector.
    • getEdge

      public void getEdge(int index, S2Shape.MutableEdge result)
      Description copied from interface: S2Shape
      Returns the edge for the given index in result. Must not return zero-length edges.
      Specified by:
      getEdge in interface S2Shape
      Parameters:
      index - which edge to set into result, from 0 to S2Shape.numEdges() - 1
    • hasInterior

      public boolean hasInterior()
      Description copied from interface: S2Shape
      Returns true if this shape has an interior, i.e. the shape consists of one or more closed non-intersecting loops.
      Specified by:
      hasInterior in interface S2Shape
    • containsOrigin

      public boolean containsOrigin()
      Description copied from interface: S2Shape
      Returns true if this shape contains S2.origin(). Should return false for shapes that do not have an interior.
      Specified by:
      containsOrigin in interface S2Shape
    • numEdges

      public int numEdges()
      Description copied from interface: S2Shape
      Returns the number of edges in this shape.
      Specified by:
      numEdges in interface S2Shape
    • numChains

      public int numChains()
      Description copied from interface: S2Shape
      Returns the number of contiguous edge chains in the shape. For example, a shape whose edges are [AB, BC, CD, AE, EF] may consist of two chains [A, B, C, D] and [A, E, F]. Every chain is assigned a chain id numbered sequentially starting from zero.

      An empty shape has no chains. A full shape (which contains the entire globe) has one chain with no edges. Other shapes should have at least one chain, and the sum of all valid chain lengths should equal S2Shape.numEdges() (that is, edges may only be used by a single chain).

      Note that it is always acceptable to implement this method by returning S2Shape.numEdges() (i.e. every chain consists of a single edge), but this may reduce the efficiency of some algorithms.

      Specified by:
      numChains in interface S2Shape
    • getChainStart

      public int getChainStart(int chainId)
      Description copied from interface: S2Shape
      Returns the first edge id corresponding to the edge chain for the given chain id. The edge chains must form contiguous, non-overlapping ranges that cover the entire range of edge ids.
      Specified by:
      getChainStart in interface S2Shape
      Parameters:
      chainId - which edge chain to return its start, from 0 to S2Shape.numChains() - 1
    • getChainLength

      public int getChainLength(int chainId)
      Description copied from interface: S2Shape
      Returns the number of edge ids corresponding to the edge chain for the given chain id. The edge chains must form contiguous, non-overlapping ranges that cover the entire range of edge ids.
      Specified by:
      getChainLength in interface S2Shape
      Parameters:
      chainId - which edge chain to return its length, from 0 to S2Shape.numChains() - 1
    • getChainEdge

      public void getChainEdge(int chainId, int offset, S2Shape.MutableEdge result)
      Description copied from interface: S2Shape
      Returns the edge for the given chain id and offset in result. Must not return zero-length edges.
      Specified by:
      getChainEdge in interface S2Shape
      Parameters:
      chainId - which chain contains the edge to return, from 0 to S2Shape.numChains() - 1
      offset - position from chain start for the edge to return, from 0 to S2Shape.getChainLength(int) - 1
    • getChainVertex

      public S2Point getChainVertex(int chainId, int edgeOffset)
      Description copied from interface: S2Shape
      Returns the start point of the edge that would be returned by S2Shape.getChainEdge(int, int, com.google.common.geometry.S2Shape.MutableEdge), or the endpoint of the last edge if edgeOffset==getChainLength(chainId).
      Specified by:
      getChainVertex in interface S2Shape
    • dimension

      public int dimension()
      Description copied from interface: S2Shape
      Returns the dimension of the geometry represented by this shape.
      • 0 - Point geometry. Each point is represented as a degenerate edge.
      • 1 - Polyline geometry. Polyline edges may be degenerate. A shape may represent any number of polylines. Polylines edges may intersect.
      • 2 - Polygon geometry. Edges should be oriented such that the polygon interior is always on the left. In theory the edges may be returned in any order, but typically the edges are organized as a collection of edge chains where each chain represents one polygon loop. Polygons may have degeneracies, e.g., degenerate edges or sibling pairs consisting of an edge and its corresponding reversed edge. A polygon loop may also be full (containing all points on the sphere); by convention this is represented as a chain with no edges.

      Note that this method allows degenerate geometry of different dimensions to be distinguished, e.g., it allows a point to be distinguished from a polyline or polygon that has been simplified to a single point.

      Specified by:
      dimension in interface S2Shape
    • get

      public S2Edge get(int index)
      Specified by:
      get in interface List<S2Edge>
      Specified by:
      get in class AbstractList<S2Edge>
    • size

      public int size()
      Specified by:
      size in interface Collection<S2Edge>
      Specified by:
      size in interface List<S2Edge>
      Specified by:
      size in class AbstractCollection<S2Edge>