QuadEdge (Core 2.1.6 API)

java.lang.Object
- org.tinfour.edge.QuadEdge

All Implemented Interfaces:

IQuadEdge
```
public class QuadEdge
extends Object
implements IQuadEdge
```
A representation of an edge with forward and reverse links on one side and counterpart links attached to its dual (other side).
This concept is based on the structure popularized by Guibas, L. and Stolfi, J. (1985) "Primitives for the manipulation of subdivisions and the computation of Voronoi diagrams" ACM Transactions on Graphics, 4(2), 1985, p. 75-123.

Constructor Summary

Constructors
Constructor and Description

QuadEdge(int index)
Construct the edge and its dual assigning the pair the specified index.

Constructors
Constructor and Description
`QuadEdge(int index)` Construct the edge and its dual assigning the pair the specified index.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear()` Sets all vertices and link references to null (the link to a dual is not affected).
`boolean`	`equals(Object o)` An implementation of the equals method which check for a matching reference.
`Vertex`	`getA()` Gets the initial vertex for this edge.
`Vertex`	`getB()` Gets the second vertex for this edge.
`int`	`getBaseIndex()` Gets the index of the "base" side of a bi-directional edge.
`QuadEdge`	`getBaseReference()` Gets the reference to the side-zero edge of the pair.
`int`	`getConstraintIndex()` Gets the index of the constraint associated with this edge.
`QuadEdge`	`getDual()` Gets the dual edge to this instance.
`QuadEdge`	`getDualFromReverse()` Gets the dual of the reverse link.
`QuadEdge`	`getForward()` Gets the forward reference of the edge.
`QuadEdge`	`getForwardFromDual()` Gets the forward reference of the dual.
`int`	`getIndex()` Gets the index value for this edge.
`double`	`getLength()` Gets the length of the edge.
`QuadEdge`	`getReverse()` Gets the reverse reference of the edge.
`QuadEdge`	`getReverseFromDual()` Gets the reverse link of the dual.
`int`	`getSide()` Indicates which side of an edge a particular QuadEdge instance is attached to.
`int`	`hashCode()`
`boolean`	`isConstrained()` Gets the index of the constrain associated with
`boolean`	`isConstrainedRegionBorder()` Indicates whether an edge represents the border of a constrained region.
`boolean`	`isConstrainedRegionInterior()` Indicates whether the edge is in the interior of a constrained region.
`boolean`	`isConstrainedRegionMember()` Indicates whether the edge is a member of a constrained region (is in the interior or serves as the border of a polygon-based constraint).
`boolean`	`isConstraintLineMember()` Indicates whether the edge is a member of a constraint line, In some cases, a constraint line member edge may lie within a constrained region but will not lie on one of its borders.
`boolean`	`isSynthetic()` Indicates whether the synthetic flag is set for the edge.
`Iterable<IQuadEdge>`	`pinwheel()` Gets an instance of an iterable that performs a pinwheel operation.
`void`	`setA(Vertex a)` Sets the initial vertex for this edge.
`void`	`setB(Vertex b)` Sets the second (B) vertex for this edge (also the A reference of the dual edge).
`void`	`setConstrained(int constraintIndex)` Sets an edge as constrained and sets its constraint index.
`void`	`setConstrainedRegionBorderFlag()` Sets a flag indicating that the edge is an edge of a constrained region.
`void`	`setConstrainedRegionInteriorFlag()` Sets the constrained region membership flag for the edge to true.
`void`	`setConstraintIndex(int constraintIndex)` Sets the constraint index for this edge.
`void`	`setConstraintLineMemberFlag()` Sets the constraint-line member flag for the edge to true.
`void`	`setDualForward(QuadEdge e)` Sets the forward link to the dual of this edge.
`void`	`setDualReverse(QuadEdge e)` Sets the reverse link of the dual to this edge.
`void`	`setForward(QuadEdge e)` Sets the forward reference for this edge.
`protected void`	`setIndex(int index)` Sets the index value for this edge.
`void`	`setLine2D(AffineTransform transform, Line2D l2d)` Provides a convenience method for rendering edges by setting the Line2D argument with the transformed coordinates of the edge.
`void`	`setReverse(QuadEdge e)` Sets the reverse reference for this edge.
`void`	`setSynthetic(boolean status)` Sets the synthetic flag for the edge.
`void`	`setVertices(Vertex a, Vertex b)` Sets the vertices for this edge (and its dual).
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - QuadEdge
```
public QuadEdge(int index)
```
    Construct the edge and its dual assigning the pair the specified index.
    
    Parameters:
    
    index - an arbitrary integer value.
- Method Detail
  - setVertices
```
public void setVertices(Vertex a,
                        Vertex b)
```
    Sets the vertices for this edge (and its dual).
    
    Parameters:
    
    a - the initial vertex, must be a valid reference.
    
    b - the second vertex, may be a valid reference or a null for a ghost edge.
  - getA
```
public final Vertex getA()
```
    Gets the initial vertex for this edge.
    
    Specified by:
    
    getA in interface IQuadEdge
    
    Returns:
    
    a valid reference.
  - setA
```
public final void setA(Vertex a)
```
    Sets the initial vertex for this edge.
    
    Parameters:
    
    a - a valid reference.
  - getB
```
public final Vertex getB()
```
    Gets the second vertex for this edge.
    
    Specified by:
    
    getB in interface IQuadEdge
    
    Returns:
    
    a valid reference or a null for a ghost edge.
  - setB
```
public final void setB(Vertex b)
```
    Sets the second (B) vertex for this edge (also the A reference of the dual edge).
    
    Parameters:
    
    b - a valid reference or a null for a ghost edge.
  - getForward
```
public final QuadEdge getForward()
```
    Gets the forward reference of the edge.
    
    Specified by:
    
    getForward in interface IQuadEdge
    
    Returns:
    
    a valid reference.
  - getReverse
```
public final QuadEdge getReverse()
```
    Gets the reverse reference of the edge.
    
    Specified by:
    
    getReverse in interface IQuadEdge
    
    Returns:
    
    a valid reference.
  - getForwardFromDual
```
public final QuadEdge getForwardFromDual()
```
    Gets the forward reference of the dual.
    
    Specified by:
    
    getForwardFromDual in interface IQuadEdge
    
    Returns:
    
    a valid reference
  - getReverseFromDual
```
public final QuadEdge getReverseFromDual()
```
    Gets the reverse link of the dual.
    
    Specified by:
    
    getReverseFromDual in interface IQuadEdge
    
    Returns:
    
    a valid reference
  - getDualFromReverse
```
public final QuadEdge getDualFromReverse()
```
    Gets the dual of the reverse link.
    
    Specified by:
    
    getDualFromReverse in interface IQuadEdge
    
    Returns:
    
    a valid reference
  - setForward
```
public final void setForward(QuadEdge e)
```
    Sets the forward reference for this edge.
    
    Parameters:
    
    e - a valid reference
  - setReverse
```
public final void setReverse(QuadEdge e)
```
    Sets the reverse reference for this edge.
    
    Parameters:
    
    e - a valid reference
  - setDualForward
```
public final void setDualForward(QuadEdge e)
```
    Sets the forward link to the dual of this edge.
    
    Parameters:
    
    e - a valid reference
  - setDualReverse
```
public final void setDualReverse(QuadEdge e)
```
    Sets the reverse link of the dual to this edge.
    
    Parameters:
    
    e - a valid reference
  - getDual
```
public final QuadEdge getDual()
```
    Gets the dual edge to this instance.
    
    Specified by:
    
    getDual in interface IQuadEdge
    
    Returns:
    
    a valid edge.
  - getIndex
```
public int getIndex()
```
    Gets the index value for this edge.
    
    Specified by:
    
    getIndex in interface IQuadEdge
    
    Returns:
    
    an integer value
  - getBaseIndex
```
public int getBaseIndex()
```
    Description copied from interface: IQuadEdge
    
    Gets the index of the "base" side of a bi-directional edge. In Tinfour implementations, edges are bi-directional. In effect, the edge is implemented as a pair of unidirectional elements. Each element is assigned a separate index. The first element in the pair is designated as the "base" and is assigned an even-valued index. Its dual is assigned a value one greater than the base index. This method always returns an even value.
    This method can be useful in cases where an application needs to track a complete edge without regard to which side of the edge is being considered.
    
    Specified by:
    
    getBaseIndex in interface IQuadEdge
    
    Returns:
    
    a positive, even value.
  - setIndex
```
protected void setIndex(int index)
```
    Sets the index value for this edge. Because this index value is used by edge-pool implementations and for other data management activities, the scope of this method is limited to protected. The actual definition of this element is left to the application that uses it.
    
    Parameters:
    
    index - an integer value
  - getBaseReference
```
public QuadEdge getBaseReference()
```
    Gets the reference to the side-zero edge of the pair.
    
    Specified by:
    
    getBaseReference in interface IQuadEdge
    
    Returns:
    
    a link to the side-zero edge of the pair.
  - getConstraintIndex
```
public int getConstraintIndex()
```
    Gets the index of the constraint associated with this edge. Constraint index values must be in the range 0 to Integer.MAX_VALUE, with negative numbers being reserved for internal use by the Tinfour library,
    
    Specified by:
    
    getConstraintIndex in interface IQuadEdge
    
    Returns:
    
    if constrained, a positive integer; otherwise, a negative value.
  - setConstraintIndex
```
public void setConstraintIndex(int constraintIndex)
```
    Description copied from interface: IQuadEdge
    
    Sets the constraint index for this edge. This method does not necessarily set an edge to a constrained status. In some implementations the constraint index may be used as a way of associating ordinary edges with a neighboring constraint. Constraint index values must be positive integers. The range of supported values will depend on the specific class that implements this interface. Please refer to the class documentation for specific values.
    
    Specified by:
    
    setConstraintIndex in interface IQuadEdge
    
    Parameters:
    
    constraintIndex - a positive number indicating which constraint a particular edge is associated with.
  - isConstrained
```
public boolean isConstrained()
```
    Gets the index of the constrain associated with
    
    Specified by:
    
    isConstrained in interface IQuadEdge
    
    Returns:
    
    true if the edge is constrained; otherwise, false.
  - setConstrained
```
public void setConstrained(int constraintIndex)
```
    Description copied from interface: IQuadEdge
    
    Sets an edge as constrained and sets its constraint index. Note that once an edge is constrained, it cannot be set to a non-constrained status. Constraint index values must be positive integers. The range of supported values will depend on the specific class that implements this interface. Please refer to the class documentation for specific values.
    
    Specified by:
    
    setConstrained in interface IQuadEdge
    
    Parameters:
    
    constraintIndex - positive number indicating which constraint a particular edge is associated with.
  - clear
```
public void clear()
```
    Sets all vertices and link references to null (the link to a dual is not affected).
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getLength
```
public double getLength()
```
    Gets the length of the edge.
    
    Specified by:
    
    getLength in interface IQuadEdge
    
    Returns:
    
    a positive floating point value
  - getSide
```
public int getSide()
```
    Indicates which side of an edge a particular QuadEdge instance is attached to. The side value is a strictly arbitrary index used for algorithms that need to be able to assign a unique index to both sides of an edge.
    
    Specified by:
    
    getSide in interface IQuadEdge
    
    Returns:
    
    a value of 0 or 1.
  - equals
```
public boolean equals(Object o)
```
    An implementation of the equals method which check for a matching reference.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    o - a valid reference or a null
    
    Returns:
    
    true if the specified reference matches this.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - isConstrainedRegionMember
```
public boolean isConstrainedRegionMember()
```
    Description copied from interface: IQuadEdge
    
    Indicates whether the edge is a member of a constrained region (is in the interior or serves as the border of a polygon-based constraint). A constrained region member is not necessarily a constrained edge.
    
    Specified by:
    
    isConstrainedRegionMember in interface IQuadEdge
    
    Returns:
    
    true if the edge is a member of an region; otherwise false.
  - isConstrainedRegionInterior
```
public boolean isConstrainedRegionInterior()
```
    Description copied from interface: IQuadEdge
    
    Indicates whether the edge is in the interior of a constrained region. Both sides of the edge lie within the interior of the region. All points along the edge will lie within the interior of the region with the possible exception of the endpoints. The endpoints may lie on the border of the region. An interior edge for a constrained region is not a constrained edge. Interior edges are also classified as "member" edges of a constrained region.
    
    Specified by:
    
    isConstrainedRegionInterior in interface IQuadEdge
    
    Returns:
    
    true if the edge is in the interior of an region; otherwise false.
  - isConstrainedRegionBorder
```
public boolean isConstrainedRegionBorder()
```
    Description copied from interface: IQuadEdge
    
    Indicates whether an edge represents the border of a constrained region. Border edges will always be constrained. Border edges are also classified as "member" edges of a constrained region.
    
    Specified by:
    
    isConstrainedRegionBorder in interface IQuadEdge
    
    Returns:
    
    true if the edge is the border of the constrained region; otherwise, false.
  - isConstraintLineMember
```
public boolean isConstraintLineMember()
```
    Description copied from interface: IQuadEdge
    
    Indicates whether the edge is a member of a constraint line, In some cases, a constraint line member edge may lie within a constrained region but will not lie on one of its borders.
    
    Specified by:
    
    isConstraintLineMember in interface IQuadEdge
    
    Returns:
    
    true if the edge is a member of an region; otherwise false.
  - setConstraintLineMemberFlag
```
public void setConstraintLineMemberFlag()
```
    Description copied from interface: IQuadEdge
    
    Sets the constraint-line member flag for the edge to true.
    
    Specified by:
    
    setConstraintLineMemberFlag in interface IQuadEdge
  - setConstrainedRegionBorderFlag
```
public void setConstrainedRegionBorderFlag()
```
    Description copied from interface: IQuadEdge
    
    Sets a flag indicating that the edge is an edge of a constrained region.
    
    Specified by:
    
    setConstrainedRegionBorderFlag in interface IQuadEdge
  - setConstrainedRegionInteriorFlag
```
public void setConstrainedRegionInteriorFlag()
```
    Description copied from interface: IQuadEdge
    
    Sets the constrained region membership flag for the edge to true.
    
    Specified by:
    
    setConstrainedRegionInteriorFlag in interface IQuadEdge
  - setSynthetic
```
public void setSynthetic(boolean status)
```
    Description copied from interface: IQuadEdge
    
    Sets the synthetic flag for the edge. Synthetic edges are those that do not arise naturally from the TIN-building logic but are created by special operations.
    
    Specified by:
    
    setSynthetic in interface IQuadEdge
    
    Parameters:
    
    status - true if the edge is synthetic; otherwise, false.
  - isSynthetic
```
public boolean isSynthetic()
```
    Description copied from interface: IQuadEdge
    
    Indicates whether the synthetic flag is set for the edge.
    
    Specified by:
    
    isSynthetic in interface IQuadEdge
    
    Returns:
    
    true if the edge is synthetic; otherwise, false.
  - pinwheel
```
public Iterable<IQuadEdge> pinwheel()
```
    Description copied from interface: IQuadEdge
    Gets an instance of an iterable that performs a pinwheel operation. This instance may be used in a Java for statement
```
    for(IQuadEdge e: startingEdge.pinwheel()){
    }
 
```
    Specified by:
    
    pinwheel in interface IQuadEdge
    
    Returns:
    
    a valid Iterable.
  - setLine2D
```
public void setLine2D(AffineTransform transform,
                      Line2D l2d)
```
    Description copied from interface: IQuadEdge
    
    Provides a convenience method for rendering edges by setting the Line2D argument with the transformed coordinates of the edge. The affine transform is used to map vertex A and B of the edge to the specified coordinate system. The transformed coordinates are then stored in the application-supplied Line2D object.
    This method is intended to support rendering operations that may render a large number of edges using Java's Line2D class. In such cases, this method avoids the overhead involved in creating multiple Line2D instances by allowing an application to reuse a single instance multiple times.
    
    Specified by:
    
    setLine2D in interface IQuadEdge
    
    Parameters:
    
    transform - a valid affine transform
    
    l2d - a valid Line2D instance

Class QuadEdge

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

QuadEdge

Method Detail

setVertices

getA

setA

getB

setB

getForward

getReverse

getForwardFromDual

getReverseFromDual

getDualFromReverse

setForward

setReverse

setDualForward

setDualReverse

getDual

getIndex

getBaseIndex

setIndex

getBaseReference

getConstraintIndex

setConstraintIndex

isConstrained

setConstrained

clear

toString

getLength

getSide

equals

hashCode

isConstrainedRegionMember

isConstrainedRegionInterior

isConstrainedRegionBorder

isConstraintLineMember

setConstraintLineMemberFlag

setConstrainedRegionBorderFlag

setConstrainedRegionInteriorFlag

setSynthetic

isSynthetic

pinwheel

setLine2D