Package us.ihmc.euclid.tuple2D.interfaces

Interface Point2DReadOnly

All Superinterfaces:

Tuple2DReadOnly

All Known Subinterfaces:

Point2DBasics

All Known Implementing Classes:

Point2D, Point2D32

public interface Point2DReadOnly
extends Tuple2DReadOnly

Read-only interface for a 2 dimensional point.

A 2D point represents the 2D coordinates of a location on the XY-plane.

Although a point and vector hold onto the same type of information, the distinction is made between them as they represent different geometry objects and are typically not handled the same way:

• a point represents the coordinate of a location in space. A notable difference with a vector is that the distance between two points has a physical meaning. When a point is transformed with a homogeneous transformation matrix, a point's coordinates are susceptible to be scaled, rotated, and translated.
• a vector is not constrained to a location in space. Instead, a vector represents some physical quantity that has a direction and a magnitude such as: a velocity, a force, the translation from one point to another, etc. When a vector is transformed with a homogeneous transformation matrix, its components are susceptible to be scaled and rotated, but never to be translated.

Author:

Sylvain Bertrand

Method Summary

Modifier and Type	Method	Description
default double	distance(Point2DReadOnly other)	Calculates and returns the distance between this point and other.
default double	distanceFromOrigin()	Calculates and returns the distance between this point and the origin (0, 0).
default double	distanceFromOriginSquared()	Calculates and returns the square of the distance between this point and the origin (0, 0).
default double	distanceSquared(Point2DReadOnly other)	Calculates and returns the square of the distance between this point and other.
default double	distanceXY(Point3DReadOnly point3DReadOnly)	Calculates and returns the distance between this point and point3DReadOnly in the XY-plane.
default double	distanceXYSquared(Point3DReadOnly point3DReadOnly)	Calculates and returns the square of the distance between this point and point3DReadOnly in the XY-plane.
default boolean	geometricallyEquals(Point2DReadOnly other, double epsilon)	Tests if this and other represent the same point 2D to an epsilon.

Methods inherited from interface us.ihmc.euclid.tuple2D.interfaces.Tuple2DReadOnly

containsNaN, epsilonEquals, equals, get, get, get, get, get, get, get, getElement, getElement32, getX, getX32, getY, getY32

Method Detail

distance

default double distance(Point2DReadOnly other)

Calculates and returns the distance between this point and other.

Parameters:

other - the other point used to measure the distance. Not modified.

Returns:

the distance between the two points.

distanceSquared

default double distanceSquared(Point2DReadOnly other)

Calculates and returns the square of the distance between this point and other.

This method is usually preferred over distance(Point2DReadOnly) when calculation speed matters and knowledge of the actual distance does not, i.e. when comparing distances between several pairs of points.

Parameters:

other - the other point used to measure the square of the distance. Not modified.

Returns:

the square of the distance between the two points.

distanceXY

default double distanceXY(Point3DReadOnly point3DReadOnly)

Calculates and returns the distance between this point and point3DReadOnly in the XY-plane.

Effectively, this calculates the distance as follows:
d_xy = √((this.x - point3DReadOnly.x)² + (this.y - point3DReadOnly.y)²)

Parameters:

point3DReadOnly - the other point used to measure the distance.

Returns:

the distance between the two points in the XY-plane.

distanceXYSquared

default double distanceXYSquared(Point3DReadOnly point3DReadOnly)

Calculates and returns the square of the distance between this point and point3DReadOnly in the XY-plane.

Effectively, this calculates the distance squared as follows:
d_xy² = (this.x - point3DReadOnly.x)² + (this.y - point3DReadOnly.y)²

This method is usually preferred over distanceXY(Point3DReadOnly) when calculation speed matters and knowledge of the actual distance does not, i.e. when comparing distances between several pairs of points.

Parameters:

point3DReadOnly - the other point used to measure the square of the distance.

Returns:

the square of the distance between the two points in the XY-plane.

distanceFromOrigin

default double distanceFromOrigin()

Calculates and returns the distance between this point and the origin (0, 0).

Returns:

the distance between this point and the origin.

distanceFromOriginSquared

default double distanceFromOriginSquared()

Calculates and returns the square of the distance between this point and the origin (0, 0).

This method is usually preferred over distanceFromOrigin() when calculation speed matters and knowledge of the actual distance does not, i.e. when comparing distances of several points with respect to the origin.

Returns:

the square of the distance between this point and the origin.

geometricallyEquals

default boolean geometricallyEquals(Point2DReadOnly other,
                                    double epsilon)

Tests if this and other represent the same point 2D to an epsilon.

Two points are considered geometrically equal if they are at a distance of less than or equal to epsilon.

Note that this.geometricallyEquals(other, epsilon) == true does not necessarily imply this.epsilonEquals(other, epsilon) and vice versa.

Parameters:

other - the other point 2D to compare against this. Not modified.

epsilon - the maximum distance that the two points can be spaced and still considered equal.

Returns:

true if the two points represent the same geometry, false otherwise.