Class Point2D

java.lang.Object

eu.svjatoslav.sixth.e3d.geometry.Point2D

All Implemented Interfaces:

Cloneable

public class Point2D
extends Object
implements Cloneable

A mutable 2D point or vector with double-precision coordinates.

Point2D represents either a position in 2D space or a directional vector, with public x and y fields for direct access. It is commonly used for screen-space coordinates after 3D-to-2D projection.

All mutation methods return this for fluent chaining:

Point2D p = new Point2D(10, 20)
    .multiply(2.0)
    .add(new Point2D(5, 5))
    .negate();
// p is now (-25, -45)

Mutability convention:

• Imperative verbs (add, subtract, negate, multiply, divide) mutate this point and return this
• with-prefixed methods (withAdded, withSubtracted, withNegated, withMultiplied, withDivided) return a new point without modifying this one

Warning: This class is mutable with public fields. Clone before storing references that should not be shared:

Point2D safeCopy = original.clone();

See Also:

• the 3D equivalent

Field Summary

Fields

Modifier and Type	Field	Description
double	x	X coordinate (horizontal axis).
double	y	Y coordinate (vertical axis, positive = down in screen space).

Constructor Summary

Constructors

Constructor	Description
Point2D()	Creates a point at the origin (0, 0).
Point2D(double x, double y)	Creates a point with the specified coordinates.
Point2D(Point2D parent)	Creates a point by copying coordinates from another point.

Method Summary

Modifier and Type	Method	Description
Point2D	add(Point2D otherPoint)	Adds another point to this point in place.
Point2D	clone()	Creates a new point by copying this point's coordinates.
void	clone(Point2D otherPoint)	Copies coordinates from another point into this point.
Point2D	divide(double factor)	Divides both coordinates by a factor.
double	getAngleXY(Point2D anotherPoint)	Computes the angle on the X-Y plane between this point and another point.
double	getDistanceTo(Point2D anotherPoint)	Computes the Euclidean distance from this point to another point.
double	getVectorLength()	Computes the length of this vector (magnitude).
boolean	isZero()	Checks if both coordinates are zero.
Point2D	multiply(double factor)	Multiplies both coordinates by a factor.
Point2D	negate()	Negates this point's coordinates in place.
void	roundToInteger()	Rounds this point's coordinates to integer values.
Point2D	setToMiddle(Point2D p1, Point2D p2)	Sets this point to the midpoint between two other points.
Point2D	subtract(Point2D otherPoint)	Subtracts another point from this point in place.
Point3D	to3D()	Converts this 2D point to a 3D point with z = 0.
String	toString()
Point2D	withAdded(Point2D other)	Returns a new point that is the sum of this point and another.
Point2D	withDivided(double factor)	Returns a new point with coordinates divided by a factor.
Point2D	withMultiplied(double factor)	Returns a new point with coordinates multiplied by a factor.
Point2D	withNegated()	Returns a new point with negated coordinates.
Point2D	withSubtracted(Point2D other)	Returns a new point that is this point minus another.
Point2D	zero()	Resets this point's coordinates to (0, 0).

Methods inherited from class Object

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

Field Details

x

public double x

X coordinate (horizontal axis).

y

public double y

Y coordinate (vertical axis, positive = down in screen space).

Constructor Details

Point2D

public Point2D()

Creates a point at the origin (0, 0).

Point2D

public Point2D(double x,
 double y)

Creates a point with the specified coordinates.

Parameters:

x - the X coordinate

y - the Y coordinate

Point2D

public Point2D(Point2D parent)

Creates a point by copying coordinates from another point.

Parameters:

parent - the point to copy from

Method Details

add

public Point2D add(Point2D otherPoint)

Adds another point to this point in place. This point is modified, the other point is not.

Parameters:

otherPoint - the point to add

Returns:

this point (for chaining)

See Also:

• for the non-mutating version that returns a new point

isZero

public boolean isZero()

Checks if both coordinates are zero.

Returns:

true if current point coordinates are equal to zero

clone

public Point2D clone()

Creates a new point by copying this point's coordinates.

Overrides:

clone in class Object

Returns:

a new point with the same coordinates

clone

public void clone(Point2D otherPoint)

Copies coordinates from another point into this point.

Parameters:

otherPoint - the point to copy coordinates from

setToMiddle

public Point2D setToMiddle(Point2D p1,
 Point2D p2)

Sets this point to the midpoint between two other points.

Parameters:

p1 - the first point

p2 - the second point

Returns:

this point (for chaining)

getAngleXY

public double getAngleXY(Point2D anotherPoint)

Computes the angle on the X-Y plane between this point and another point.

Parameters:

anotherPoint - the other point

Returns:

the angle in radians

getDistanceTo

public double getDistanceTo(Point2D anotherPoint)

Computes the Euclidean distance from this point to another point.

Parameters:

anotherPoint - the point to compute distance to

Returns:

the distance between the two points

getVectorLength

public double getVectorLength()

Computes the length of this vector (magnitude).

Returns:

the vector length

negate

public Point2D negate()

Negates this point's coordinates in place. This point is modified.

Returns:

this point (for chaining)

See Also:

• for the non-mutating version that returns a new point

roundToInteger

public void roundToInteger()

Rounds this point's coordinates to integer values.

subtract

public Point2D subtract(Point2D otherPoint)

Subtracts another point from this point in place. This point is modified, the other point is not.

Parameters:

otherPoint - the point to subtract

Returns:

this point (for chaining)

See Also:

• for the non-mutating version that returns a new point

multiply

public Point2D multiply(double factor)

Multiplies both coordinates by a factor. This point is modified.

Parameters:

factor - the multiplier

Returns:

this point (for chaining)

See Also:

• for the non-mutating version that returns a new point

divide

public Point2D divide(double factor)

Divides both coordinates by a factor. This point is modified.

Parameters:

factor - the divisor

Returns:

this point (for chaining)

See Also:

• for the non-mutating version that returns a new point

to3D

public Point3D to3D()

Converts this 2D point to a 3D point with z = 0.

Returns:

a new 3D point with the same x, y and z = 0

zero

public Point2D zero()

Resets this point's coordinates to (0, 0).

Returns:

this point (for chaining)

toString

public String toString()

Overrides:

toString in class Object

withAdded

public Point2D withAdded(Point2D other)

Returns a new point that is the sum of this point and another. This point is not modified.

Parameters:

other - the point to add

Returns:

a new Point2D representing the sum

See Also:

• for the mutating version

withSubtracted

public Point2D withSubtracted(Point2D other)

Returns a new point that is this point minus another. This point is not modified.

Parameters:

other - the point to subtract

Returns:

a new Point2D representing the difference

See Also:

• for the mutating version

withNegated

public Point2D withNegated()

Returns a new point with negated coordinates. This point is not modified.

Returns:

a new Point2D with negated coordinates

See Also:

• for the mutating version

withMultiplied

public Point2D withMultiplied(double factor)

Returns a new point with coordinates multiplied by a factor. This point is not modified.

Parameters:

factor - the multiplier

Returns:

a new Point2D with multiplied coordinates

See Also:

• for the mutating version

withDivided

public Point2D withDivided(double factor)

Returns a new point with coordinates divided by a factor. This point is not modified.

Parameters:

factor - the divisor

Returns:

a new Point2D with divided coordinates

See Also:

• for the mutating version