org.openimaj.math.geometry.point

Class PointList

java.lang.Object

org.openimaj.math.geometry.point.PointList

All Implemented Interfaces:

Cloneable, Iterable<Point2d>, GeometricObject2d

Direct Known Subclasses:

Polygon, Polyline

public class PointList
extends Object
implements GeometricObject2d, Iterable<Point2d>, Cloneable

A base implementation of a GeometricObject2d that is a set of points in space. Even though the points are backed by a list, the class itself does not make any assumptions about the order of the points (i.e. to determine connectedness), however, subclasses might.

Author:

Jonathon Hare (jsh2@ecs.soton.ac.uk)

Field Summary

Fields

Modifier and Type	Field and Description
List<Point2d>	points The points in the PointList

Constructor Summary

Constructors

Constructor and Description
PointList(Collection<? extends Point2d> points) Construct a PointList from points
PointList(Collection<? extends Point2d> points, boolean copy) Construct a PointList from the points, possibly copying the points first
PointList(Point2d... points) Construct a PointList from points

Method Summary

Modifier and Type	Method and Description
Point2d	calculateCentroid() Get the centre of gravity of the PointList
Polygon	calculateConvexHull() Calculate the convex hull of the points using the Graham Scan algorithm.
Rectangle	calculateRegularBoundingBox() Compute the regular (oriented to the axes) bounding box of the PointList.
PointList	clone()
float	computeIntrinsicScale() Calculate the intrinsic scale of the shape.
static PointList	computeMean(Collection<PointList> shapes) Compute the mean of a set of PointLists.
Point2d	get(int i) Get the ith point
double	getHeight()
List<Line2d>	getLines()
List<Line2d>	getLines(PointListConnections conns)
double	getWidth()
Iterator<Point2d>	iterator()
double	maxX()
double	maxY()
double	minX()
double	minY()
void	rotate(double angle) Rotate the PointList about (0,0) with the given angle (in radians)
void	rotate(Point2d origin, double angle) Rotate the PointList about the given origin with the given angle (in radians)
void	scale(float sc) Scale the PointList by the given amount about (0,0).
void	scale(Point2d centre, float sc) Scale the PointList by the given amount about the given point.
void	scaleCentroid(float sc) Scale the PointList about its centre of gravity.
PointList	scaleX(float sc) Scale the PointList only in the x-direction by the given amount about (0,0).
PointList	scaleXY(float scx, float scy) Scale the PointList by the given amount about (0,0).
PointList	scaleY(float sc) Scale the PointList only in the y-direction by the given amount about (0,0).
int	size()
String	toString()
PointList	transform(Jama.Matrix transform) Apply a 3x3 transform matrix to a copy of the PointList and return it
void	translate(float x, float y) Translate the PointLists position

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

points

public List<Point2d> points

The points in the PointList

Constructor Detail

PointList

public PointList(Point2d... points)

Construct a PointList from points

Parameters:

points - the points

PointList

public PointList(Collection<? extends Point2d> points)

Construct a PointList from points

Parameters:

points - the points

PointList

public PointList(Collection<? extends Point2d> points,
                 boolean copy)

Construct a PointList from the points, possibly copying the points first

Parameters:

points - the points

copy - should the points be copied

Method Detail

rotate

public void rotate(Point2d origin,
                   double angle)

Rotate the PointList about the given origin with the given angle (in radians)

Parameters:

origin - the origin of the rotation

angle - the angle in radians

rotate

public void rotate(double angle)

Rotate the PointList about (0,0) with the given angle (in radians)

Parameters:

angle - the angle in radians

calculateRegularBoundingBox

public Rectangle calculateRegularBoundingBox()

Compute the regular (oriented to the axes) bounding box of the PointList.

Specified by:

calculateRegularBoundingBox in interface GeometricObject2d

Returns:

the regular bounding box

translate

public void translate(float x,
                      float y)

Translate the PointLists position

Specified by:

translate in interface GeometricObject2d

Parameters:

x - x-translation

y - y-translation

scale

public void scale(float sc)

Scale the PointList by the given amount about (0,0). Scalefactors between 0 and 1 shrink the PointList.

Specified by:

scale in interface GeometricObject2d

Parameters:

sc - the scale factor.

scaleX

public PointList scaleX(float sc)

Scale the PointList only in the x-direction by the given amount about (0,0). Scale factors between 0 and 1 will shrink the PointList

Parameters:

sc - The scale factor

Returns:

this PointList

scaleY

public PointList scaleY(float sc)

Scale the PointList only in the y-direction by the given amount about (0,0). Scale factors between 0 and 1 will shrink the PointList

Parameters:

sc - The scale factor

Returns:

this PointList

scaleXY

public PointList scaleXY(float scx,
                         float scy)

Scale the PointList by the given amount about (0,0). Scale factors between 0 and 1 shrink the PointList.

Parameters:

scx - the scale factor in the x direction

scy - the scale factor in the y direction.

Returns:

this PointList

scale

public void scale(Point2d centre,
                  float sc)

Scale the PointList by the given amount about the given point. Scalefactors between 0 and 1 shrink the PointList.

Specified by:

scale in interface GeometricObject2d

Parameters:

centre - the centre of the scaling operation

sc - the scale factor

scaleCentroid

public void scaleCentroid(float sc)

Scale the PointList about its centre of gravity. Scalefactors between 0 and 1 shrink the PointList.

Specified by:

scaleCentroid in interface GeometricObject2d

Parameters:

sc - the scale factor

calculateCentroid

public Point2d calculateCentroid()

Get the centre of gravity of the PointList

Specified by:

calculateCentroid in interface GeometricObject2d

Returns:

the centre of gravity of the PointList

minX

public double minX()

Specified by:

minX in interface GeometricObject2d

Returns:

the minimum x-ordinate of all vertices

minY

public double minY()

Specified by:

minY in interface GeometricObject2d

Returns:

the minimum y-ordinate of all vertices

maxX

public double maxX()

Specified by:

maxX in interface GeometricObject2d

Returns:

the maximum x-ordinate of all vertices

maxY

public double maxY()

Specified by:

maxY in interface GeometricObject2d

Returns:

the maximum y-ordinate of all vertices

getWidth

public double getWidth()

Specified by:

getWidth in interface GeometricObject2d

Returns:

the width of the regular bounding box

getHeight

public double getHeight()

Specified by:

getHeight in interface GeometricObject2d

Returns:

the height of the regular bounding box

transform

public PointList transform(Jama.Matrix transform)

Apply a 3x3 transform matrix to a copy of the PointList and return it

Specified by:

transform in interface GeometricObject2d

Parameters:

transform - 3x3 transform matrix

Returns:

the transformed PointList

iterator

public Iterator<Point2d> iterator()

Specified by:

iterator in interface Iterable<Point2d>

See Also:

Iterable.iterator()

toString

public String toString()

Overrides:

toString in class Object

computeMean

public static PointList computeMean(Collection<PointList> shapes)

Compute the mean of a set of PointLists. It is assumed that the number of points in the PointLists is equal, and that their is a one-to-one correspondance between the ith point in each list.

Parameters:

shapes - the shapes to average

Returns:

the average shape

size

public int size()

Returns:

the number of points in the list

computeIntrinsicScale

public float computeIntrinsicScale()

Calculate the intrinsic scale of the shape. This is the RMS distance of all the points from the centroid.

Returns:

the scale of the object.

get

public Point2d get(int i)

Get the ith point

Parameters:

i - the index of the point

Returns:

the ith point

getLines

public List<Line2d> getLines()

Returns:

A list of Line2d assuming the points in this list are connected in order

getLines

public List<Line2d> getLines(PointListConnections conns)

Parameters:

conns -

Returns:

calls PointListConnections.getLines(PointList) with this

clone

public PointList clone()

Overrides:

clone in class Object

calculateConvexHull

public Polygon calculateConvexHull()

Calculate the convex hull of the points using the Graham Scan algorithm.

Returns:

the convex hull

See Also:

GrahamScan