maspack.geometry

Class ConvexPolygon2d

java.lang.Object

maspack.geometry.Polygon2d

maspack.geometry.ConvexPolygon2d

All Implemented Interfaces:

java.lang.Iterable<Vertex2d>, HasRenderProps, IsRenderable, IsSelectable, Renderable

public class ConvexPolygon2d
extends Polygon2d

Field Summary

Fields inherited from interface maspack.render.IsRenderable

TRANSPARENT, TWO_DIMENSIONAL

Constructor Summary

Constructors

Constructor and Description
ConvexPolygon2d()
ConvexPolygon2d(double[] coords)
ConvexPolygon2d(Point2d[] pnts)

Method Summary

Modifier and Type	Method and Description
double	area()
void	computeAndSetHull(java.util.List<Point2d> input, double angTol)
static java.util.ArrayList<Point2d>	computeHull(java.util.List<Point2d> input, double angTol) Computes a 2D convex hull for a set of input points, using the Monotone Chain algorithm, by A.
static int[]	computeHullIndices(java.util.Collection<Point2d> input, double angTol) Computes the indices of a 2D convex hull within a set of input points, using the Monotone Chain algorithm, by A.
static java.util.ArrayList<Point2d>	computeOld(java.util.Collection<Point2d> input, double tol) Computes a 2D convex hull from a set on input points, using the Graham Scan algorithm, which is O(n log n).
int	pointIsInside(Point2d pnt) Returns 1 or -1 depending on whether pnt is (strictly) inside or outside of poly.

Methods inherited from class maspack.geometry.Polygon2d

addVertex, appendVertex, clear, computeArea, computeAreaIntegrals, computeLength, createRenderProps, epsilonEquals, equals, getBounds, getCentroid, getFirstVertex, getLastVertex, getMaxCoordinate, getPoints, getRenderHints, getRenderProps, getSelection, getVertices, intersectRay, inverseTransform, isConsistent, isConvex, isConvex, isEmpty, isSelectable, iterator, nearestEdge, numSelectionQueriesNeeded, numVertices, prependVertex, prerender, render, render, scan, set, set, set, set, set, setRenderProps, shiftFirstVertex, shiftVertices, simpleConvexHull, simpleConvexHull, toString, toString, toString, transform, updateBounds, updateBounds

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

ConvexPolygon2d

public ConvexPolygon2d()

ConvexPolygon2d

public ConvexPolygon2d(double[] coords)

ConvexPolygon2d

public ConvexPolygon2d(Point2d[] pnts)

Method Detail

area

public double area()

computeOld

public static java.util.ArrayList<Point2d> computeOld(java.util.Collection<Point2d> input,
                                                      double tol)

Computes a 2D convex hull from a set on input points, using the Graham Scan algorithm, which is O(n log n).

computeHullIndices

public static int[] computeHullIndices(java.util.Collection<Point2d> input,
                                       double angTol)

Computes the indices of a 2D convex hull within a set of input points, using the Monotone Chain algorithm, by A. M. Andrew, 1979 (which is a variation on the Graham scan method).

Parameters:

input - points from which the hull should be formed

angTol - if > 0, specifies an angular tolerance which should be used to remove nearly colinear points

Returns:

list of the indices of the point in input which form the hull, in counter-clockwise order

computeHull

public static java.util.ArrayList<Point2d> computeHull(java.util.List<Point2d> input,
                                                       double angTol)

Computes a 2D convex hull for a set of input points, using the Monotone Chain algorithm, by A. M. Andrew, 1979 (which is a variation on the Graham scan method).

Parameters:

input - points from which the hull should be formed

angTol - if > 0, specifies an angular tolerance which should be used to remove nearly colinear points

Returns:

a list of points, copied from input, which form the hull in counter-clockwise order

computeAndSetHull

public void computeAndSetHull(java.util.List<Point2d> input,
                              double angTol)

pointIsInside

public int pointIsInside(Point2d pnt)

Returns 1 or -1 depending on whether pnt is (strictly) inside or outside of poly.

Returns:

1 for inside and -1 for outside