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

java.lang.Object
- org.locationtech.jts.triangulate.tri.Tri

```
public class Tri
extends Object
```
A memory-efficient representation of a triangle in a triangulation. Contains three vertices, and links to adjacent Tris for each edge. Tris are constructed independently, and if needed linked into a triangulation using TriangulationBuilder.
An edge of a Tri in a triangulation is called a boundary edge if it has no adjacent triangle. The set of Tris containing boundary edges are called the triangulation border.

Author:

Martin Davis

Constructor Summary

Constructors
Constructor and Description

Tri(Coordinate p0, Coordinate p1, Coordinate p2)
Creates a triangle with the given vertices.

Constructors
Constructor and Description
`Tri(Coordinate p0, Coordinate p1, Coordinate p2)` Creates a triangle with the given vertices.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static double`	`area(List<? extends Tri> triList)` Computes the area of a set of Tris.
`static Tri`	`create(Coordinate[] pts)` Creates a triangle from an array with three vertex coordinates.
`static Tri`	`create(Coordinate p0, Coordinate p1, Coordinate p2)` Creates a triangle with the given vertices.
`int`	`degree(int index, List<? extends Tri> triList)` Computes the degree of a Tri vertex, which is the number of tris containing it.
`void`	`flip(int index)` Interchanges the vertices of this triangle and a neighbor so that their common edge becomes the the other diagonal of the quadrilateral they form.
`Tri`	`getAdjacent(int index)` Gets the triangle adjacent to an edge.
`double`	`getArea()` Gets the area of the triangle.
`Coordinate`	`getCoordinate(int index)` Gets the coordinate for a vertex.
`int`	`getIndex(Coordinate p)` Gets the index of the triangle vertex which has a given coordinate (if any).
`int`	`getIndex(Tri tri)` Gets the edge index which a triangle is adjacent to (if any), based on the adjacent triangle link.
`double`	`getLength()` Gets the perimeter length of the triangle.
`double`	`getLength(int edgeIndex)` Gets the length of an edge of the triangle.
`boolean`	`hasAdjacent()` Tests if this tri has any adjacent tris.
`boolean`	`hasAdjacent(int index)` Tests if there is an adjacent triangle to an edge.
`boolean`	`isAdjacent(Tri tri)` Tests if a triangle is adjacent to some edge of this triangle.
`boolean`	`isBorder()` Tests if a tri contains a boundary edge, and thus on the border of the triangulation containing it.
`boolean`	`isBoundary(int index)` Tests if an edge is on the boundary of a triangulation.
`boolean`	`isInteriorVertex(int index)` Tests if a tri vertex is interior.
`Coordinate`	`midpoint(int edgeIndex)` Computes a coordinate for the midpoint of a triangle edge.
`static int`	`next(int index)` Computes the vertex or edge index which is the next one (clockwise) around the triangle.
`int`	`numAdjacent()` Computes the number of triangle adjacent to this triangle.
`static int`	`oppEdge(int vertexIndex)` Gets the index of the edge opposite a vertex.
`static int`	`oppVertex(int edgeIndex)` Gets the index of the vertex opposite an edge.
`static int`	`prev(int index)` Computes the vertex or edge index which is the previous one (counter-clockwise) around the triangle.
`void`	`remove()` Removes this triangle from a triangulation.
`void`	`remove(List<? extends Tri> triList)` Removes this tri from the triangulation containing it.
`void`	`setAdjacent(Coordinate pt, Tri tri)` Sets the triangle adjacent to the edge originating at a given vertex.
`void`	`setAdjacent(Tri tri0, Tri tri1, Tri tri2)` Sets the adjacent triangles.
`void`	`setTri(int edgeIndex, Tri tri)` Sets the triangle adjacent to an edge.
`Tri`	`split(Coordinate p)` Spits a triangle by a point located inside the triangle.
`static Geometry`	`toGeometry(Collection<Tri> tris, GeometryFactory geomFact)` Creates a `GeometryCollection` of `Polygon`s representing the triangles in a list.
`Polygon`	`toPolygon(GeometryFactory geomFact)` Creates a `Polygon` representing this triangle.
`String`	`toString()`
`void`	`validate()` Validates that a tri is correct.
`static void`	`validate(List<Tri> triList)` Validates a list of Tris.
`void`	`validateAdjacent(int index)` Validates that the vertices of an adjacent linked triangle are correct.

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

- Constructor Detail
  - Tri
```
public Tri(Coordinate p0,
           Coordinate p1,
           Coordinate p2)
```
    Creates a triangle with the given vertices. The vertices should be oriented clockwise.
    
    Parameters:
    
    p0 - the first triangle vertex
    
    p1 - the second triangle vertex
    
    p2 - the third triangle vertex
- Method Detail
  - toGeometry
```
public static Geometry toGeometry(Collection<Tri> tris,
                                  GeometryFactory geomFact)
```
    Creates a GeometryCollection of Polygons representing the triangles in a list.
    
    Parameters:
    
    tris - a collection of Tris
    
    geomFact - the GeometryFactory to use
    
    Returns:
    
    the polygons for the triangles
  - area
```
public static double area(List<? extends Tri> triList)
```
    Computes the area of a set of Tris.
    
    Parameters:
    
    triList - a set of Tris
    
    Returns:
    
    the total area of the triangles
  - validate
```
public static void validate(List<Tri> triList)
```
    Validates a list of Tris.
    
    Parameters:
    
    triList - the tris to validate
  - create
```
public static Tri create(Coordinate p0,
                         Coordinate p1,
                         Coordinate p2)
```
    Creates a triangle with the given vertices. The vertices should be oriented clockwise.
    
    Parameters:
    
    p0 - the first triangle vertex
    
    p1 - the second triangle vertex
    
    p2 - the third triangle vertex
    
    Returns:
    
    the created triangle
  - create
```
public static Tri create(Coordinate[] pts)
```
    Creates a triangle from an array with three vertex coordinates. The vertices should be oriented clockwise.
    
    Parameters:
    
    pts - the array of vertex coordinates
    
    Returns:
    
    the created triangle
  - setAdjacent
```
public void setAdjacent(Tri tri0,
                        Tri tri1,
                        Tri tri2)
```
    Sets the adjacent triangles. The vertices of the adjacent triangles are assumed to match the appropriate vertices in this triangle.
    
    Parameters:
    
    tri0 - the triangle adjacent to edge 0
    
    tri1 - the triangle adjacent to edge 1
    
    tri2 - the triangle adjacent to edge 2
  - setAdjacent
```
public void setAdjacent(Coordinate pt,
                        Tri tri)
```
    Sets the triangle adjacent to the edge originating at a given vertex. The vertices of the adjacent triangles are assumed to match the appropriate vertices in this triangle.
    
    Parameters:
    
    pt - the edge start point
    
    tri - the adjacent triangle
  - setTri
```
public void setTri(int edgeIndex,
                   Tri tri)
```
    Sets the triangle adjacent to an edge. The vertices of the adjacent triangle are assumed to match the appropriate vertices in this triangle.
    
    Parameters:
    
    edgeIndex - the edge triangle is adjacent to
    
    tri - the adjacent triangle
  - split
```
public Tri split(Coordinate p)
```
    Spits a triangle by a point located inside the triangle. Creates the three new resulting triangles with adjacent links set correctly. Returns the new triangle whose 0'th vertex is the splitting point.
    
    Parameters:
    
    p - the point to insert
    
    Returns:
    
    the new triangle whose 0'th vertex is p
  - flip
```
public void flip(int index)
```
    Interchanges the vertices of this triangle and a neighbor so that their common edge becomes the the other diagonal of the quadrilateral they form. Neighbour triangle links are modified accordingly.
    
    Parameters:
    
    index - the index of the adjacent tri to flip with
  - degree
```
public int degree(int index,
                  List<? extends Tri> triList)
```
    Computes the degree of a Tri vertex, which is the number of tris containing it. This must be done by searching the entire triangulation, since the containing tris may not be adjacent or edge-connected.
    
    Parameters:
    
    index - the vertex index
    
    triList - the triangulation
    
    Returns:
    
    the degree of the vertex
  - remove
```
public void remove(List<? extends Tri> triList)
```
    Removes this tri from the triangulation containing it. All links between the tri and adjacent ones are nulled.
    
    Parameters:
    
    triList - the triangulation
  - remove
```
public void remove()
```
    Removes this triangle from a triangulation. All adjacent references and the references to this Tri in the adjacent Tris are set to null
  validate public void validate() Validates that a tri is correct. Currently just checks that orientation is CW. validateAdjacent public void validateAdjacent(int index) Validates that the vertices of an adjacent linked triangle are correct. Parameters: index - the index of the adjacent triangle getCoordinate public Coordinate getCoordinate(int index) Gets the coordinate for a vertex. This is the start vertex of the edge. Parameters: index - the vertex (edge) index Returns: the vertex coordinate getIndex public int getIndex(Coordinate p) Gets the index of the triangle vertex which has a given coordinate (if any). This is also the index of the edge which originates at the vertex. Parameters: p - the coordinate to find Returns: the vertex index, or -1 if it is not in the triangle getIndex public int getIndex(Tri tri) Gets the edge index which a triangle is adjacent to (if any), based on the adjacent triangle link. Parameters: tri - the tri to find Returns: the index of the edge adjacent to the triangle, or -1 if not found getAdjacent public Tri getAdjacent(int index) Gets the triangle adjacent to an edge. Parameters: index - the edge index Returns: the adjacent triangle (may be null) hasAdjacent public boolean hasAdjacent() Tests if this tri has any adjacent tris. Returns: true if there is at least one adjacent tri hasAdjacent public boolean hasAdjacent(int index) Tests if there is an adjacent triangle to an edge. Parameters: index - the edge index Returns: true if there is a triangle adjacent to edge isAdjacent public boolean isAdjacent(Tri tri) Tests if a triangle is adjacent to some edge of this triangle. Parameters: tri - the triangle to test Returns: true if the triangle is adjacent See Also: getIndex(Tri) numAdjacent public int numAdjacent() Computes the number of triangle adjacent to this triangle. This is a number in the range [0,2]. Returns: the number of adjacent triangles isInteriorVertex public boolean isInteriorVertex(int index) Tests if a tri vertex is interior. A vertex of a triangle is interior if it is fully surrounded by other triangles. Parameters: index - the vertex index Returns: true if the vertex is interior isBorder public boolean isBorder() Tests if a tri contains a boundary edge, and thus on the border of the triangulation containing it. Returns: true if the tri is on the border of the triangulation isBoundary public boolean isBoundary(int index) Tests if an edge is on the boundary of a triangulation. Parameters: index - index of an edge Returns: true if the edge is on the boundary next public static int next(int index) Computes the vertex or edge index which is the next one (clockwise) around the triangle. Parameters: index - the index Returns: the next index value prev public static int prev(int index) Computes the vertex or edge index which is the previous one (counter-clockwise) around the triangle. Parameters: index - the index Returns: the previous index value oppVertex public static int oppVertex(int edgeIndex) Gets the index of the vertex opposite an edge. Parameters: edgeIndex - the edge index Returns: the index of the opposite vertex oppEdge public static int oppEdge(int vertexIndex) Gets the index of the edge opposite a vertex. Parameters: vertexIndex - the index of the vertex Returns: the index of the opposite edge midpoint public Coordinate midpoint(int edgeIndex) Computes a coordinate for the midpoint of a triangle edge. Parameters: edgeIndex - the edge index Returns: the midpoint of the triangle edge getArea public double getArea() Gets the area of the triangle. Returns: the area of the triangle getLength public double getLength() Gets the perimeter length of the triangle. Returns: the perimeter length getLength public double getLength(int edgeIndex) Gets the length of an edge of the triangle. Parameters: edgeIndex - the edge index Returns: the edge length toPolygon public Polygon toPolygon(GeometryFactory geomFact) Creates a Polygon representing this triangle. Parameters: geomFact - the geometry factory Returns: a polygon toString public String toString() Overrides: toString in class Object

Class Tri

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Tri

Method Detail

toGeometry

area

validate

create

create

setAdjacent

setAdjacent

setTri

split

flip

degree

remove

remove

validate

validateAdjacent

getCoordinate

getIndex

getIndex

getAdjacent

hasAdjacent

hasAdjacent

isAdjacent

numAdjacent

isInteriorVertex

isBorder

isBoundary

next

prev

oppVertex

oppEdge

midpoint

getArea

getLength

getLength

toPolygon

toString