Package org.openstreetmap.josm.tools

Class ShapeClipper

java.lang.Object

org.openstreetmap.josm.tools.ShapeClipper

public final class ShapeClipper
extends java.lang.Object

Tools to clip a shape based on the Sutherland-Hodgman algorithm. See https://en.wikipedia.org/wiki/Sutherland%E2%80%93Hodgman_algorithm

Since:

14583

Field Summary

Fields

Modifier and Type	Field	Description
private static int	BOTTOM
private static int	LEFT
private static int	RIGHT
private static int	TOP

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ShapeClipper()

Method Summary

Modifier and Type	Method	Description
private static boolean	addToResult(java.awt.geom.Path2D.Double result, double[] points, int num, java.awt.geom.Rectangle2D bbox, java.awt.geom.Rectangle2D clippingRect)	Clip extracted segment if needed and add it to result if not completely outside of clipping rectangle.
static java.awt.geom.Path2D.Double	clipShape(java.awt.Shape shape, java.awt.geom.Rectangle2D clippingRect)	Clip a given (closed) shape with a given rectangle.
private static java.awt.geom.Path2D.Double	clipSinglePathWithSutherlandHodgman(double[] points, int num, java.awt.geom.Rectangle2D bbox, java.awt.geom.Rectangle2D clippingRect)	Clip a single path with a given rectangle using the Sutherland-Hodgman algorithm.
private static java.awt.geom.Path2D.Double	pointsToPath2D(double[] points, int num)	Convert a list of points to a Path2D.Double

Methods inherited from class java.lang.Object

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

Field Detail

LEFT

private static final int LEFT

See Also:

Constant Field Values

TOP

private static final int TOP

See Also:

Constant Field Values

RIGHT

private static final int RIGHT

See Also:

Constant Field Values

BOTTOM

private static final int BOTTOM

See Also:

Constant Field Values

Constructor Detail

ShapeClipper

private ShapeClipper()

Method Detail

clipShape

public static java.awt.geom.Path2D.Double clipShape(java.awt.Shape shape,
                                                    java.awt.geom.Rectangle2D clippingRect)

Clip a given (closed) shape with a given rectangle.

Parameters:

shape - the subject shape to clip

clippingRect - the clipping rectangle

Returns:

the intersection of the shape and the rectangle or null if they don't intersect or the shape is not closed. The intersection may contain dangling edges.

addToResult

private static boolean addToResult(java.awt.geom.Path2D.Double result,
                                   double[] points,
                                   int num,
                                   java.awt.geom.Rectangle2D bbox,
                                   java.awt.geom.Rectangle2D clippingRect)

Clip extracted segment if needed and add it to result if not completely outside of clipping rectangle.

Parameters:

result - the path that will describe the clipped shape (modified)

points - array of x/y pairs

num - the number of valid values in points

bbox - the bounding box of the path

clippingRect - the clipping rectangle

Returns:

true if data was added to result

pointsToPath2D

private static java.awt.geom.Path2D.Double pointsToPath2D(double[] points,
                                                          int num)

Convert a list of points to a Path2D.Double

Parameters:

points - array of x/y pairs

num - the number of valid values in points

Returns:

the path or null if the path describes a point or line.

clipSinglePathWithSutherlandHodgman

private static java.awt.geom.Path2D.Double clipSinglePathWithSutherlandHodgman(double[] points,
                                                                               int num,
                                                                               java.awt.geom.Rectangle2D bbox,
                                                                               java.awt.geom.Rectangle2D clippingRect)

Clip a single path with a given rectangle using the Sutherland-Hodgman algorithm. This is much faster compared to the area.intersect method, but may create dangling edges.

Parameters:

points - array of x/y pairs

num - the number of valid values in points

bbox - the bounding box of the path

clippingRect - the clipping rectangle

Returns:

the clipped path as a Path2D.Double or null if the result is empty