javafx.geometry.Point2D Maven / Gradle / Ivy
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package javafx.geometry;
import javafx.animation.Interpolatable;
import javafx.beans.NamedArg;
// PENDING_DOC_REVIEW of this whole class
/**
* A 2D geometric point that usually represents the x, y coordinates.
* It can also represent a relative magnitude vector's x, y magnitudes.
* @since JavaFX 2.0
*/
public class Point2D implements Interpolatable {
/**
* Point or vector with both coordinates set to 0.
*/
public static final Point2D ZERO = new Point2D(0.0, 0.0);
/**
* The x coordinate.
*
* @defaultValue 0.0
*/
private final double x;
/**
* The x coordinate.
* @return the x coordinate
*/
public final double getX() {
return x;
}
/**
* The y coordinate.
*
* @defaultValue 0.0
*/
private final double y;
/**
* The y coordinate.
* @return the y coordinate
*/
public final double getY() {
return y;
}
/**
* Cache the hash code to make computing hashes faster.
*/
private int hash = 0;
/**
* Creates a new instance of {@code Point2D}.
* @param x the x coordinate of the point
* @param y the y coordinate of the point
*/
public Point2D(@NamedArg("x") double x, @NamedArg("y") double y) {
this.x = x;
this.y = y;
}
/**
* Computes the distance between this point and point {@code (x1, y1)}.
*
* @param x1 the x coordinate of other point
* @param y1 the y coordinate of other point
* @return the distance between this point and point {@code (x1, y1)}.
*/
public double distance(double x1, double y1) {
double a = getX() - x1;
double b = getY() - y1;
return Math.sqrt(a * a + b * b);
}
/**
* Computes the distance between this point and the specified {@code point}.
*
* @param point the other point
* @return the distance between this point and the specified {@code point}.
* @throws NullPointerException if the specified {@code point} is null
*/
public double distance(Point2D point) {
return distance(point.getX(), point.getY());
}
/**
* Returns a point with the specified coordinates added to the coordinates
* of this point.
* @param x the X coordinate addition
* @param y the Y coordinate addition
* @return the point with added coordinates
* @since JavaFX 8.0
*/
public Point2D add(double x, double y) {
return new Point2D(
getX() + x,
getY() + y);
}
/**
* Returns a point with the coordinates of the specified point added to the
* coordinates of this point.
* @param point the point whose coordinates are to be added
* @return the point with added coordinates
* @throws NullPointerException if the specified {@code point} is null
* @since JavaFX 8.0
*/
public Point2D add(Point2D point) {
return add(point.getX(), point.getY());
}
/**
* Returns a point with the specified coordinates subtracted from
* the coordinates of this point.
* @param x the X coordinate subtraction
* @param y the Y coordinate subtraction
* @return the point with subtracted coordinates
* @since JavaFX 8.0
*/
public Point2D subtract(double x, double y) {
return new Point2D(
getX() - x,
getY() - y);
}
/**
* Returns a point with the coordinates of this point multiplied
* by the specified factor
* @param factor the factor multiplying the coordinates
* @return the point with multiplied coordinates
* @since JavaFX 8.0
*/
public Point2D multiply(double factor) {
return new Point2D(getX() * factor, getY() * factor);
}
/**
* Returns a point with the coordinates of the specified point subtracted
* from the coordinates of this point.
* @param point the point whose coordinates are to be subtracted
* @return the point with subtracted coordinates
* @throws NullPointerException if the specified {@code point} is null
* @since JavaFX 8.0
*/
public Point2D subtract(Point2D point) {
return subtract(point.getX(), point.getY());
}
/**
* Normalizes the relative magnitude vector represented by this instance.
* Returns a vector with the same direction and magnitude equal to 1.
* If this is a zero vector, a zero vector is returned.
* @return the normalized vector represented by a {@code Point2D} instance
* @since JavaFX 8.0
*/
public Point2D normalize() {
final double mag = magnitude();
if (mag == 0.0) {
return new Point2D(0.0, 0.0);
}
return new Point2D(
getX() / mag,
getY() / mag);
}
/**
* Returns a point which lies in the middle between this point and the
* specified coordinates.
* @param x the X coordinate of the second endpoint
* @param y the Y coordinate of the second endpoint
* @return the point in the middle
* @since JavaFX 8.0
*/
public Point2D midpoint(double x, double y) {
return new Point2D(
x + (getX() - x) / 2.0,
y + (getY() - y) / 2.0);
}
/**
* Returns a point which lies in the middle between this point and the
* specified point.
* @param point the other endpoint
* @return the point in the middle
* @throws NullPointerException if the specified {@code point} is null
* @since JavaFX 8.0
*/
public Point2D midpoint(Point2D point) {
return midpoint(point.getX(), point.getY());
}
/**
* Computes the angle (in degrees) between the vector represented
* by this point and the specified vector.
* @param x the X magnitude of the other vector
* @param y the Y magnitude of the other vector
* @return the angle between the two vectors measured in degrees
* @since JavaFX 8.0
*/
public double angle(double x, double y) {
final double ax = getX();
final double ay = getY();
final double delta = (ax * x + ay * y) / Math.sqrt(
(ax * ax + ay * ay) * (x * x + y * y));
if (delta > 1.0) {
return 0.0;
}
if (delta < -1.0) {
return 180.0;
}
return Math.toDegrees(Math.acos(delta));
}
/**
* Computes the angle (in degrees) between the vector represented
* by this point and the vector represented by the specified point.
* @param point the other vector
* @return the angle between the two vectors measured in degrees,
* {@code NaN} if any of the two vectors is a zero vector
* @throws NullPointerException if the specified {@code point} is null
* @since JavaFX 8.0
*/
public double angle(Point2D point) {
return angle(point.getX(), point.getY());
}
/**
* Computes the angle (in degrees) between the three points with this point
* as a vertex.
* @param p1 one point
* @param p2 other point
* @return angle between the vectors (this, p1) and (this, p2) measured
* in degrees, {@code NaN} if the three points are not different
* from one another
* @throws NullPointerException if {@code p1} or {@code p2} is null
* @since JavaFX 8.0
*/
public double angle(Point2D p1, Point2D p2) {
final double x = getX();
final double y = getY();
final double ax = p1.getX() - x;
final double ay = p1.getY() - y;
final double bx = p2.getX() - x;
final double by = p2.getY() - y;
final double delta = (ax * bx + ay * by) / Math.sqrt(
(ax * ax + ay * ay) * (bx * bx + by * by));
if (delta > 1.0) {
return 0.0;
}
if (delta < -1.0) {
return 180.0;
}
return Math.toDegrees(Math.acos(delta));
}
/**
* Computes magnitude (length) of the relative magnitude vector represented
* by this instance.
* @return magnitude of the vector
* @since JavaFX 8.0
*/
public double magnitude() {
final double x = getX();
final double y = getY();
return Math.sqrt(x * x + y * y);
}
/**
* Computes dot (scalar) product of the vector represented by this instance
* and the specified vector.
* @param x the X magnitude of the other vector
* @param y the Y magnitude of the other vector
* @return the dot product of the two vectors
* @since JavaFX 8.0
*/
public double dotProduct(double x, double y) {
return getX() * x + getY() * y;
}
/**
* Computes dot (scalar) product of the vector represented by this instance
* and the specified vector.
* @param vector the other vector
* @return the dot product of the two vectors
* @throws NullPointerException if the specified {@code vector} is null
* @since JavaFX 8.0
*/
public double dotProduct(Point2D vector) {
return dotProduct(vector.getX(), vector.getY());
}
/**
* Computes cross product of the vector represented by this instance
* and the specified vector.
* @param x the X magnitude of the other vector
* @param y the Y magnitude of the other vector
* @return the cross product of the two vectors
* @since JavaFX 8.0
*/
public Point3D crossProduct(double x, double y) {
final double ax = getX();
final double ay = getY();
return new Point3D(
0, 0, ax * y - ay * x);
}
/**
* Computes cross product of the vector represented by this instance
* and the specified vector.
* @param vector the other vector
* @return the cross product of the two vectors
* @throws NullPointerException if the specified {@code vector} is null
* @since JavaFX 8.0
*/
public Point3D crossProduct(Point2D vector) {
return crossProduct(vector.getX(), vector.getY());
}
/**
* {@inheritDoc}
*
* @since 13
*/
@Override
public Point2D interpolate(Point2D endValue, double t) {
if (t <= 0.0) return this;
if (t >= 1.0) return endValue;
return new Point2D(
getX() + (endValue.getX() - getX()) * t,
getY() + (endValue.getY() - getY()) * t
);
}
/**
* Indicates whether some other object is "equal to" this one.
*
* @param obj the reference object with which to compare
* @return true if this point is the same as the obj argument; false otherwise
*/
@Override public boolean equals(Object obj) {
if (obj == this) return true;
if (obj instanceof Point2D) {
Point2D other = (Point2D) obj;
return getX() == other.getX() && getY() == other.getY();
} else return false;
}
/**
* Returns a hash code value for the point.
* @return a hash code value for the point.
*/
@Override public int hashCode() {
if (hash == 0) {
long bits = 7L;
bits = 31L * bits + Double.doubleToLongBits(getX());
bits = 31L * bits + Double.doubleToLongBits(getY());
hash = (int) (bits ^ (bits >> 32));
}
return hash;
}
/**
* Returns a string representation of this {@code Point2D}.
* This method is intended to be used only for informational purposes.
* The content and format of the returned string might vary between
* implementations.
* The returned string might be empty but cannot be {@code null}.
*/
@Override public String toString() {
return "Point2D [x = " + getX() + ", y = " + getY() + "]";
}
}
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