QuadEdgeTriangle (org.locationtech.jts:jts-core 1.20.0 API)

java.lang.Object
- org.locationtech.jts.triangulate.quadedge.QuadEdgeTriangle

```
public class QuadEdgeTriangle
extends Object
```
Models a triangle formed from QuadEdges in a QuadEdgeSubdivision which forms a triangulation. The class provides methods to access the topological and geometric properties of the triangle and its neighbours in the triangulation. Triangle vertices are ordered in CCW orientation in the structure.
QuadEdgeTriangles support having an external data attribute attached to them. Alternatively, this class can be subclassed and attributes can be defined in the subclass. Subclasses will need to define their own BuilderVisitor class and createOn method.

Version:

1.0

Author:

Martin Davis

Constructor Summary

Constructors
Constructor and Description

QuadEdgeTriangle(QuadEdge[] edge)
Creates a new triangle from the given edges.

Constructors
Constructor and Description
`QuadEdgeTriangle(QuadEdge[] edge)` Creates a new triangle from the given edges.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`contains(Coordinate pt)`
`static boolean`	`contains(QuadEdge[] tri, Coordinate pt)` Tests whether the point pt is contained in the triangle defined by 3 `QuadEdge`es.
`static boolean`	`contains(Vertex[] tri, Coordinate pt)` Tests whether the point pt is contained in the triangle defined by 3 `Vertex`es.
`static List`	`createOn(QuadEdgeSubdivision subdiv)` Creates `QuadEdgeTriangle`s for all facets of a `QuadEdgeSubdivision` representing a triangulation.
`QuadEdgeTriangle`	`getAdjacentTriangleAcrossEdge(int edgeIndex)`
`int`	`getAdjacentTriangleEdgeIndex(int i)`
`Coordinate`	`getCoordinate(int i)`
`Coordinate[]`	`getCoordinates()`
`Object`	`getData()` Gets the external data value for this triangle.
`QuadEdge`	`getEdge(int i)`
`int`	`getEdgeIndex(QuadEdge e)` Gets the index for the given edge of this triangle
`int`	`getEdgeIndex(Vertex v)` Gets the index for the edge that starts at vertex v.
`QuadEdge[]`	`getEdges()`
`void`	`getEdgeSegment(int i, LineSegment seg)`
`Polygon`	`getGeometry(GeometryFactory fact)`
`QuadEdgeTriangle[]`	`getNeighbours()` Gets the neighbours of this triangle.
`List`	`getTrianglesAdjacentToVertex(int vertexIndex)` Gets the triangles which are adjacent (include) to a given vertex of this triangle.
`Vertex`	`getVertex(int i)`
`Vertex[]`	`getVertices()` Gets the vertices for this triangle.
`boolean`	`isBorder()` Tests whether this triangle is adjacent to the outside of the subdivision.
`boolean`	`isBorder(int i)`
`boolean`	`isLive()`
`void`	`kill()`
`static int`	`nextIndex(int index)` Finds the next index around the triangle.
`void`	`setData(Object data)` Sets the external data value for this triangle.
`static Geometry`	`toPolygon(QuadEdge[] e)`
`static Geometry`	`toPolygon(Vertex[] v)`
`String`	`toString()`

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - QuadEdgeTriangle
```
public QuadEdgeTriangle(QuadEdge[] edge)
```
    Creates a new triangle from the given edges.
    
    Parameters:
    
    edge - an array of the edges of the triangle in CCW order
- Method Detail
  - createOn
```
public static List createOn(QuadEdgeSubdivision subdiv)
```
    Creates QuadEdgeTriangles for all facets of a QuadEdgeSubdivision representing a triangulation. The data attributes of the QuadEdges in the subdivision will be set to point to the triangle which contains that edge. This allows tracing the neighbour triangles of any given triangle.
    
    Parameters:
    
    subdiv - the QuadEdgeSubdivision to create the triangles on.
    
    Returns:
    
    a List of the created QuadEdgeTriangles
  - contains
```
public static boolean contains(Vertex[] tri,
                               Coordinate pt)
```
    Tests whether the point pt is contained in the triangle defined by 3 Vertexes.
    
    Parameters:
    
    tri - an array containing at least 3 Vertexes
    
    pt - the point to test
    
    Returns:
    
    true if the point is contained in the triangle
  - contains
```
public static boolean contains(QuadEdge[] tri,
                               Coordinate pt)
```
    Tests whether the point pt is contained in the triangle defined by 3 QuadEdgees.
    
    Parameters:
    
    tri - an array containing at least 3 QuadEdges
    
    pt - the point to test
    
    Returns:
    
    true if the point is contained in the triangle
  - toPolygon
```
public static Geometry toPolygon(Vertex[] v)
```
  - toPolygon
```
public static Geometry toPolygon(QuadEdge[] e)
```
  - nextIndex
```
public static int nextIndex(int index)
```
    Finds the next index around the triangle. Index may be an edge or vertex index.
    
    Parameters:
    
    index -
    
    Returns:
    
    the next index
  - setData
```
public void setData(Object data)
```
    Sets the external data value for this triangle.
    
    Parameters:
    
    data - an object containing external data
  - getData
```
public Object getData()
```
    Gets the external data value for this triangle.
    
    Returns:
    
    the data object
  - kill
```
public void kill()
```
  - isLive
```
public boolean isLive()
```
  - getEdges
```
public QuadEdge[] getEdges()
```
  - getEdge
```
public QuadEdge getEdge(int i)
```
  - getVertex
```
public Vertex getVertex(int i)
```
  - getVertices
```
public Vertex[] getVertices()
```
    Gets the vertices for this triangle.
    
    Returns:
    
    a new array containing the triangle vertices
  - getCoordinate
```
public Coordinate getCoordinate(int i)
```
  - getEdgeIndex
```
public int getEdgeIndex(QuadEdge e)
```
    Gets the index for the given edge of this triangle
    
    Parameters:
    
    e - a QuadEdge
    
    Returns:
    
    the index of the edge in this triangle or -1 if the edge is not an edge of this triangle
  - getEdgeIndex
```
public int getEdgeIndex(Vertex v)
```
    Gets the index for the edge that starts at vertex v.
    
    Parameters:
    
    v - the vertex to find the edge for
    
    Returns:
    
    the index of the edge starting at the vertex or -1 if the vertex is not in the triangle
  - getEdgeSegment
```
public void getEdgeSegment(int i,
                           LineSegment seg)
```
  - getCoordinates
```
public Coordinate[] getCoordinates()
```
  - contains
```
public boolean contains(Coordinate pt)
```
  - getGeometry
```
public Polygon getGeometry(GeometryFactory fact)
```
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - isBorder
```
public boolean isBorder()
```
    Tests whether this triangle is adjacent to the outside of the subdivision.
    
    Returns:
    
    true if the triangle is adjacent to the subdivision exterior
  - isBorder
```
public boolean isBorder(int i)
```
  - getAdjacentTriangleAcrossEdge
```
public QuadEdgeTriangle getAdjacentTriangleAcrossEdge(int edgeIndex)
```
  - getAdjacentTriangleEdgeIndex
```
public int getAdjacentTriangleEdgeIndex(int i)
```
  - getTrianglesAdjacentToVertex
```
public List getTrianglesAdjacentToVertex(int vertexIndex)
```
    Gets the triangles which are adjacent (include) to a given vertex of this triangle.
    
    Parameters:
    
    vertexIndex - the vertex to query
    
    Returns:
    
    a list of the vertex-adjacent triangles
  - getNeighbours
```
public QuadEdgeTriangle[] getNeighbours()
```
    Gets the neighbours of this triangle. If there is no neighbour triangle, the array element is null
    
    Returns:
    
    an array containing the 3 neighbours of this triangle

Class QuadEdgeTriangle

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

QuadEdgeTriangle

Method Detail

createOn

contains

contains

toPolygon

toPolygon

nextIndex

setData

getData

kill

isLive

getEdges

getEdge

getVertex

getVertices

getCoordinate

getEdgeIndex

getEdgeIndex

getEdgeSegment

getCoordinates

contains

getGeometry

toString

isBorder

isBorder

getAdjacentTriangleAcrossEdge

getAdjacentTriangleEdgeIndex

getTrianglesAdjacentToVertex

getNeighbours