org.kynosarges.tektosyne.geometry

Class VoronoiResults

java.lang.Object

org.kynosarges.tektosyne.geometry.VoronoiResults

public final class VoronoiResults
extends java.lang.Object

Contains the results of the Voronoi algorithm. Holds the Voronoi diagram and Delaunay triangulation found by the Voronoi algorithm when both results were requested.

Field Summary

Fields

Modifier and Type	Field and Description
RectD	clippingBounds The clipping bounds for the entire Voronoi diagram.
PointD[]	generatorSites The generator sites for the Voronoi diagram and Delaunay triangulation.
VoronoiEdge[]	voronoiEdges The edge list for the Voronoi diagram.
PointD[]	voronoiVertices The vertex list for the Voronoi diagram.

Method Summary

Modifier and Type	Method and Description
void	clearVoronoiRegions() Clears the voronoiRegions() cache.
LineD[]	clipDelaunayEdges(RectD bounds) Clips the edge list for the Delaunay triangulation to the specified bounds.
LineD[]	delaunayEdges() Gets the edge list for the Delaunay triangulation.
Subdivision	toDelaunaySubdivision(boolean addRegions) Converts all delaunayEdges() to a planar Subdivision, using the default clippingBounds.
Subdivision	toDelaunaySubdivision(RectD bounds, boolean addRegions) Converts all delaunayEdges() to a planar Subdivision, using the specified clipping bounds.
PointD[][]	voronoiRegions() Gets the regions of the Voronoi diagram.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

clippingBounds

public final RectD clippingBounds

The clipping bounds for the entire Voronoi diagram. Contains the RectD that was actually used by the Voronoi algorithm, which may be larger than that originally supplied to Voronoi.findAll(org.kynosarges.tektosyne.geometry.PointD[]).

All Voronoi edges are terminated with a pseudo-vertex in voronoiVertices when they intersect the clippingBounds. No voronoiVertices lie outside the clippingBounds.

Moreover, the four corners of the clippingBounds are always part of some voronoiRegions() that were originally unbounded. voronoiVertices does not usually contain these corner vertices.

generatorSites

public final PointD[] generatorSites

The generator sites for the Voronoi diagram and Delaunay triangulation. Holds the PointD coordinates whose Voronoi diagram and Delaunay triangulation are provided by the VoronoiResults. This is the original PointD array that was supplied to the Voronoi algorithm and resulted in the VoronoiResults. This field is provided merely for convenience.

voronoiEdges

public final VoronoiEdge[] voronoiEdges

The edge list for the Voronoi diagram. Holds all edges in the Voronoi diagram, stored as double index pairs relative to the generatorSites and voronoiVertices arrays.

The complete Voronoi diagram is defined both by the voronoiVertices and by the voronoiEdges that connect the vertices. All coordinates are bounded by the current clippingBounds.

voronoiVertices

public final PointD[] voronoiVertices

The vertex list for the Voronoi diagram. Holds the PointD coordinates of all vertices in the Voronoi diagram.

The complete Voronoi diagram is defined both by the voronoiVertices and by the voronoiEdges that connect the vertices. All coordinates are bounded by the current clippingBounds.

Method Detail

delaunayEdges

public LineD[] delaunayEdges()

Gets the edge list for the Delaunay triangulation. Returns an array of the same size as voronoiEdges. Each LineD element connects the generatorSites indicated by VoronoiEdge.site1 and VoronoiEdge.site2 of the VoronoiEdge at the same index position.

Returns:

an array of all LineD edges in the Delaunay triangulation

voronoiRegions

public PointD[][] voronoiRegions()

Gets the regions of the Voronoi diagram. Calculated on first success, then cached for repeated access. All coordinates are bounded by the current clippingBounds.

The PointD array for each generator site contains the vertices of a convex polygon. The last vertex is implicitly assumed to be connected with the first vertex. Most vertices also appear in voronoiVertices, except for the four corners of the clippingBounds which terminate the outermost regions.

Returns:

an array containing PointD polygons that represent the Voronoi regions corresponding to the same generatorSites indices

clearVoronoiRegions

public void clearVoronoiRegions()

Clears the voronoiRegions() cache. This will cause voronoiRegions() to be recalculated (with identical results) when requested again. Call this method to reduce memory consumption when the cached voronoiRegions() are no longer required, e.g. after creating VoronoiMap.

clipDelaunayEdges

public LineD[] clipDelaunayEdges(RectD bounds)

Clips the edge list for the Delaunay triangulation to the specified bounds. Returns all delaunayEdges() whose corresponding voronoiEdges element fulfils two conditions:

• VoronoiEdge.site1 and VoronoiEdge.site2 both fall within the specified bounds.
• The line segment indicated by VoronoiEdge.vertex1 and VoronoiEdge.vertex2 intersects the specified bounds.

In other words, clipDelaunayEdges(org.kynosarges.tektosyne.geometry.RectD) selects those delaunayEdges() that fall entirely within bounds, and which connect two voronoiRegions() that share a common border within bounds.

Parameters:

bounds - a RectD indicating the clipping bounds for all delaunayEdges()

Returns:

an array of all delaunayEdges() which intersect bounds, as defined above

Throws:

java.lang.NullPointerException - if bounds is null

toDelaunaySubdivision

public Subdivision toDelaunaySubdivision(boolean addRegions)

Converts all delaunayEdges() to a planar Subdivision, using the default clippingBounds.

Parameters:

addRegions - true to add all voronoiRegions() with the corresponding generatorSites to the Subdivision.vertexRegions() of the new Subdivision, else false

Returns:

a new Subdivision whose Subdivision.edges() correspond to the delaunayEdges() of the VoronoiResults

toDelaunaySubdivision

public Subdivision toDelaunaySubdivision(RectD bounds,
                                         boolean addRegions)

Converts all delaunayEdges() to a planar Subdivision, using the specified clipping bounds. The specified bounds determine the subset of generatorSites and delaunayEdges() that is stored in the new Subdivision, as described in clipDelaunayEdges(org.kynosarges.tektosyne.geometry.RectD).

If addRegions is true, the polygons added to Subdivision.vertexRegions() are also clipped the specified bounds.

Parameters:

bounds - a RectD indicating the clipping bounds for all delaunayEdges()

addRegions - true to add all voronoiRegions() with the corresponding generatorSites to the Subdivision.vertexRegions() of the new Subdivision, else false

Returns:

a new Subdivision whose Subdivision.edges() correspond to the delaunayEdges() of the VoronoiResults

Throws:

java.lang.NullPointerException - if bounds is null