de.javagl.geom

Class Projections

java.lang.Object

de.javagl.geom.Projections

public class Projections
extends Object

Utility methods related to projections

Method Summary

Modifier and Type	Method and Description
static double	computeRelativeProjectionLocation(double x0, double y0, double x1, double y1, double x, double y) Computes the relative location of the projection of the point (x,y) on the line (x0,y0)-(x1,y1).
static Point2D	dropPerpendicular(double x0, double y0, double x1, double y1, double x, double y, Point2D result) Drop the perpendicular on the line (x0,y0)-(x1,y1) from the point (x,y) and store the result in the given point and return it.
static Point2D	dropPerpendicular(Line2D line, Point2D p, Point2D result) Drop the perpendicular on the line from the point p and store the result in the given point and return it.
static Point2D	dropPerpendicular(Point2D p0, Point2D p1, Point2D p, Point2D result) Drop the perpendicular on the line p0-p1 from the point p and store the result in the given point and return it.

Methods inherited from class java.lang.Object

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

Method Detail

dropPerpendicular

public static Point2D dropPerpendicular(Line2D line,
                                        Point2D p,
                                        Point2D result)

Drop the perpendicular on the line from the point p and store the result in the given point and return it. If the given result point is null, then a new point will be created and returned

Parameters:

line - The line

p - The point to drop from

result - The point that will store the result

Returns:

The result

dropPerpendicular

public static Point2D dropPerpendicular(Point2D p0,
                                        Point2D p1,
                                        Point2D p,
                                        Point2D result)

Drop the perpendicular on the line p0-p1 from the point p and store the result in the given point and return it. If the given result point is null, then a new point will be created and returned

Parameters:

p0 - The start point of the line

p1 - The end point of the line

p - The point to drop from

result - The point that will store the result

Returns:

The result

dropPerpendicular

public static Point2D dropPerpendicular(double x0,
                                        double y0,
                                        double x1,
                                        double y1,
                                        double x,
                                        double y,
                                        Point2D result)

Drop the perpendicular on the line (x0,y0)-(x1,y1) from the point (x,y) and store the result in the given point and return it. If the given result point is null, then a new point will be created and returned

Parameters:

x0 - The x-coordinate of the start point of the line

y0 - The y-coordinate of the start point of the line

x1 - The x-coordinate of the end point of the line

y1 - The y-coordinate of the end point of the line

x - The x-coordinate of the point to drop from

y - The y-coordinate of the point to drop from

result - The point that will store the result

Returns:

The result

computeRelativeProjectionLocation

public static double computeRelativeProjectionLocation(double x0,
                                                       double y0,
                                                       double x1,
                                                       double y1,
                                                       double x,
                                                       double y)

Computes the relative location of the projection of the point (x,y) on the line (x0,y0)-(x1,y1). It will be the relative location, meaning that if the projection is at (x0,y0), then the result will be 0.0, and if the projection is at (x1,y1), then the result will be 1.0.

Parameters:

x0 - The x-coordinate of the start point of the line

y0 - The y-coordinate of the start point of the line

x1 - The x-coordinate of the end point of the line

y1 - The y-coordinate of the end point of the line

x - The x-coordinate of the point to drop from

y - The y-coordinate of the point to drop from

Returns:

The relative projection location