org.jhotdraw.geom

Class BezierPath

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

java.util.ArrayList<BezierPath.Node>

org.jhotdraw.geom.BezierPath

All Implemented Interfaces:

java.awt.Shape, java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<BezierPath.Node>, java.util.Collection<BezierPath.Node>, java.util.List<BezierPath.Node>, java.util.RandomAccess

public class BezierPath
extends java.util.ArrayList<BezierPath.Node>
implements java.awt.Shape, java.io.Serializable, java.lang.Cloneable

BezierPath allows the construction of paths consisting of straight lines, quadratic curves and cubic curves.

A BezierPath is defined by its nodes. Each node has three control points: C0, C1, C2. A mask defines which control points are in use. At a node, the path passes through C0. C1 controls the curve going towards C0. C2 controls the curve going away from C0.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BezierPath.Node Defines a vertex (node) of the bezier path.

Field Summary

Fields

Modifier and Type	Field and Description
static int	C0_MASK Constant for having only control point C0 in effect.
static int	C1_MASK Constant for having control point C1 in effect (in addition to C0).
static int	C1C2_MASK Constant for having control points C1 and C2 in effect (in addition to C0).
static int	C2_MASK Constant for having control point C2 in effect (in addition to C0).

Constructor Summary

Constructors

Constructor and Description
BezierPath() Creates a new instance.

Method Summary

Modifier and Type	Method and Description
void	add(double x, double y) Adds a node to the path.
void	add(int ctrlMask, java.awt.geom.Point2D.Double c0, java.awt.geom.Point2D.Double c1, java.awt.geom.Point2D.Double c2) Adds a node to the path.
void	add(java.awt.geom.Point2D.Double c0) Adds a node to the path.
void	addPolyline(java.util.Collection<java.awt.geom.Point2D.Double> points) Adds a set of nodes to the path.
void	arcTo(double rx, double ry, double xAxisRotation, boolean largeArcFlag, boolean sweepFlag, double x, double y) Adds an elliptical arc, defined by two radii, an angle from the x-axis, a flag to choose the large arc or not, a flag to indicate if we increase or decrease the angles and the final point of the arc.
java.awt.geom.Point2D.Double	chop(java.awt.geom.Point2D.Double p) Returns a point on the edge of the bezier path which crosses the line from the center of the bezier path to the specified point.
BezierPath	clone() Creates a deep copy of the BezierPath.
boolean	contains(double x, double y)
boolean	contains(double x, double y, double w, double h)
boolean	contains(java.awt.geom.Point2D p)
boolean	contains(java.awt.geom.Rectangle2D r)
void	curveTo(double x1, double y1, double x2, double y2, double x3, double y3) Adds a cubic curve to the bezier path.
int	findSegment(java.awt.geom.Point2D.Double find, double tolerance) Gets the segment of the polyline that is hit by the given Point2D.Double.
java.awt.geom.Point2D.Double	get(int nodeIndex, int ctrlIndex) Convenience method for getting a single control point of a node.
java.awt.Rectangle	getBounds()
java.awt.geom.Rectangle2D.Double	getBounds2D()
java.awt.geom.Point2D.Double	getCenter() Returns the point at the center of the bezier path.
double	getLengthOfPath(double flatness) Returns the length of the path.
java.awt.geom.PathIterator	getPathIterator(java.awt.geom.AffineTransform at)
java.awt.geom.PathIterator	getPathIterator(java.awt.geom.AffineTransform at, double flatness)
java.awt.geom.Point2D.Double	getPointOnPath(double relative, double flatness) Returns a relative point on the path.
double	getRelativePositionOnPath(java.awt.geom.Point2D.Double find, double flatness) Returns the relative position of the specified point on the path.
int	getWindingRule() Gets winding rule for filling the bezier path.
int	indexOfOutermostNode() Return the index of the node that is the furthest away from the center
boolean	intersects(double x, double y, double w, double h)
boolean	intersects(java.awt.geom.Rectangle2D r)
void	invalidatePath() This must be called after the BezierPath has been changed.
boolean	isClosed()
int	joinSegments(java.awt.geom.Point2D.Double join, double tolerance) Joins two segments into one if the given Point2D.Double hits a node of the bezier path.
void	lineTo(double x1, double y1) Adds a (at least) linear 'curve' to the bezier path.
void	moveTo(double x1, double y1) Adds the first node to the bezier path.
boolean	outlineContains(java.awt.geom.Point2D.Double p, double tolerance) Returns true, if the outline of this bezier path contains the specified point.
void	quadTo(double x1, double y1, double x2, double y2) Adds a (at least) quadratic curve to the bezier path.
void	set(int nodeIndex, int ctrlIndex, java.awt.geom.Point2D.Double p) Convenience method for changing a single control point of a node.
void	setClosed(boolean newValue)
void	setTo(BezierPath that) Sets all values of this bezier path to that bezier path, so that this path becomes identical to that path.
void	setWindingRule(int newValue) Sets winding rule for filling the bezier path.
int	splitSegment(java.awt.geom.Point2D.Double split, double tolerance) Splits the segment at the given Point2D.Double if a segment was hit.
java.awt.geom.Path2D.Double	toGeneralPath() Converts the BezierPath into a Path2D.Double.
java.awt.geom.Point2D.Double[]	toPolygonArray() Creates a polygon/polyline array of the bezier path which only includes the C0 control points of the bezier nodes.
void	transform(java.awt.geom.AffineTransform tx) Transforms the BezierPath.
void	validatePath() Recomputes the BezierPath, if it is invalid.

Methods inherited from class java.util.ArrayList

add, add, addAll, addAll, clear, contains, ensureCapacity, forEach, get, indexOf, isEmpty, iterator, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, removeIf, replaceAll, retainAll, set, size, sort, spliterator, subList, toArray, toArray, trimToSize

Methods inherited from class java.util.AbstractList

equals, hashCode

Methods inherited from class java.util.AbstractCollection

containsAll, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

containsAll, equals, hashCode

Methods inherited from interface java.util.Collection

parallelStream, stream

Field Detail

C0_MASK

public static final int C0_MASK

Constant for having only control point C0 in effect. C0 is the point through whitch the curve passes.

See Also:

Constant Field Values

C1_MASK

public static final int C1_MASK

Constant for having control point C1 in effect (in addition to C0). C1 controls the curve going towards C0.

See Also:

Constant Field Values

C2_MASK

public static final int C2_MASK

Constant for having control point C2 in effect (in addition to C0). C2 controls the curve going away from C0.

See Also:

Constant Field Values

C1C2_MASK

public static final int C1C2_MASK

Constant for having control points C1 and C2 in effect (in addition to C0).

See Also:

Constant Field Values

Constructor Detail

BezierPath

public BezierPath()

Creates a new instance.

Method Detail

add

public void add(java.awt.geom.Point2D.Double c0)

Adds a node to the path.

This is a convenience method for adding a node with a single control point C0 to the path.

add

public void add(double x,
                double y)

Adds a node to the path.

This is a convenience method for adding a node with a single control point C0 to the path.

add

public void add(int ctrlMask,
                java.awt.geom.Point2D.Double c0,
                java.awt.geom.Point2D.Double c1,
                java.awt.geom.Point2D.Double c2)

Adds a node to the path.

This is a convenience method for adding a node with three control points C0, C1 and C2, and a mask.

Parameters:

ctrlMask - An or-combination of C0_MASK,C1_MASK and C2_MASK.

c0 - The coordinates of the C0 control point.

c1 - The coordinates of the C1 control point.

c2 - The coordinates of the C2 control point.

addPolyline

public void addPolyline(java.util.Collection<java.awt.geom.Point2D.Double> points)

Adds a set of nodes to the path.

Convenience method for adding multiple nodes with a single control point C0.

set

public void set(int nodeIndex,
                int ctrlIndex,
                java.awt.geom.Point2D.Double p)

Convenience method for changing a single control point of a node.

Parameters:

nodeIndex - The index of the node.

ctrlIndex - Either C0_MASK, C1_MASK or C2_MASK.

p - The control point. The coordinates will be cloned.

get

public java.awt.geom.Point2D.Double get(int nodeIndex,
                                        int ctrlIndex)

Convenience method for getting a single control point of a node.

Parameters:

nodeIndex - The index of the node.

ctrlIndex - Either C0_MASK, C1_MASK or C2_MASK.

Returns:

Returns a clone of the control point.

invalidatePath

public void invalidatePath()

This must be called after the BezierPath has been changed.

validatePath

public void validatePath()

Recomputes the BezierPath, if it is invalid.

toGeneralPath

public java.awt.geom.Path2D.Double toGeneralPath()

Converts the BezierPath into a Path2D.Double.

contains

public boolean contains(java.awt.geom.Point2D p)

Specified by:

contains in interface java.awt.Shape

outlineContains

public boolean outlineContains(java.awt.geom.Point2D.Double p,
                               double tolerance)

Returns true, if the outline of this bezier path contains the specified point.

Parameters:

p - The point to be tested.

tolerance - The tolerance for the test.

intersects

public boolean intersects(java.awt.geom.Rectangle2D r)

Specified by:

intersects in interface java.awt.Shape

getPathIterator

public java.awt.geom.PathIterator getPathIterator(java.awt.geom.AffineTransform at)

Specified by:

getPathIterator in interface java.awt.Shape

getPathIterator

public java.awt.geom.PathIterator getPathIterator(java.awt.geom.AffineTransform at,
                                                  double flatness)

Specified by:

getPathIterator in interface java.awt.Shape

contains

public boolean contains(java.awt.geom.Rectangle2D r)

Specified by:

contains in interface java.awt.Shape

intersects

public boolean intersects(double x,
                          double y,
                          double w,
                          double h)

Specified by:

intersects in interface java.awt.Shape

getBounds2D

public java.awt.geom.Rectangle2D.Double getBounds2D()

Specified by:

getBounds2D in interface java.awt.Shape

getBounds

public java.awt.Rectangle getBounds()

Specified by:

getBounds in interface java.awt.Shape

contains

public boolean contains(double x,
                        double y,
                        double w,
                        double h)

Specified by:

contains in interface java.awt.Shape

contains

public boolean contains(double x,
                        double y)

Specified by:

contains in interface java.awt.Shape

setClosed

public void setClosed(boolean newValue)

isClosed

public boolean isClosed()

clone

public BezierPath clone()

Creates a deep copy of the BezierPath.

Overrides:

clone in class java.util.ArrayList<BezierPath.Node>

transform

public void transform(java.awt.geom.AffineTransform tx)

Transforms the BezierPath.

Parameters:

tx - the transformation.

setTo

public void setTo(BezierPath that)

Sets all values of this bezier path to that bezier path, so that this path becomes identical to that path.

getCenter

public java.awt.geom.Point2D.Double getCenter()

Returns the point at the center of the bezier path.

chop

public java.awt.geom.Point2D.Double chop(java.awt.geom.Point2D.Double p)

Returns a point on the edge of the bezier path which crosses the line from the center of the bezier path to the specified point. If no edge crosses the line, the nearest C0 control point is returned.

indexOfOutermostNode

public int indexOfOutermostNode()

Return the index of the node that is the furthest away from the center

getPointOnPath

@Nullable
public java.awt.geom.Point2D.Double getPointOnPath(double relative,
                                                             double flatness)

Returns a relative point on the path. Where 0 is the start point of the path and 1 is the end point of the path.

Parameters:

relative - a value between 0 and 1.

getLengthOfPath

public double getLengthOfPath(double flatness)

Returns the length of the path.

Parameters:

flatness - the flatness used to approximate the length.

getRelativePositionOnPath

public double getRelativePositionOnPath(java.awt.geom.Point2D.Double find,
                                        double flatness)

Returns the relative position of the specified point on the path.

Parameters:

flatness - the flatness used to approximate the length.

Returns:

relative position on path, this is a number between 0 and 1. Returns -1, if the point is not on the path.

findSegment

public int findSegment(java.awt.geom.Point2D.Double find,
                       double tolerance)

Gets the segment of the polyline that is hit by the given Point2D.Double.

Returns:

the index of the segment or -1 if no segment was hit.

joinSegments

public int joinSegments(java.awt.geom.Point2D.Double join,
                        double tolerance)

Joins two segments into one if the given Point2D.Double hits a node of the bezier path.

Returns:

the index of the joined segment or -1 if no segment was joined.

splitSegment

public int splitSegment(java.awt.geom.Point2D.Double split,
                        double tolerance)

Splits the segment at the given Point2D.Double if a segment was hit.

Returns:

the index of the segment or -1 if no segment was hit.

moveTo

public void moveTo(double x1,
                   double y1)

Adds the first node to the bezier path.

This is a convenience method for adding the first node with a single control point C0 to the bezier path.

lineTo

public void lineTo(double x1,
                   double y1)

Adds a (at least) linear 'curve' to the bezier path.

If the previous node has no C2 control point the line will be straight (linear), otherwise the line will be quadratic.

This is a convenience method for adding a node with a single control point C0.

The bezier path must already have at least one node.

quadTo

public void quadTo(double x1,
                   double y1,
                   double x2,
                   double y2)

Adds a (at least) quadratic curve to the bezier path.

If the previous node has no C2 control point the line will be quadratic otherwise the line will be cubic.

This is a convenience method for adding a node with control point C0 and C1 (incoming curve) to the bezier path.

The bezier path must already have at least one node.

curveTo

public void curveTo(double x1,
                    double y1,
                    double x2,
                    double y2,
                    double x3,
                    double y3)

Adds a cubic curve to the bezier path.

This is a convenience method for adding a node with control point C0 and C1 (incoming curve) to the bezier path, and also specifying the control point C2 (outgoing curve) of the previous node.

The bezier path must already have at least one node.

arcTo

public void arcTo(double rx,
                  double ry,
                  double xAxisRotation,
                  boolean largeArcFlag,
                  boolean sweepFlag,
                  double x,
                  double y)

Adds an elliptical arc, defined by two radii, an angle from the x-axis, a flag to choose the large arc or not, a flag to indicate if we increase or decrease the angles and the final point of the arc.

As specified in http://www.w3.org/TR/SVG/paths.html#PathDataEllipticalArcCommands

The implementation of this method has been derived from Apache Batik class org.apache.batik.ext.awt.geom.ExtendedGeneralPath#computArc

Parameters:

rx - the x radius of the ellipse

ry - the y radius of the ellipse

xAxisRotation - the angle from the x-axis of the current coordinate system to the x-axis of the ellipse in degrees.

largeArcFlag - the large arc flag. If true the arc spanning less than or equal to 180 degrees is chosen, otherwise the arc spanning greater than 180 degrees is chosen

sweepFlag - the sweep flag. If true the line joining center to arc sweeps through decreasing angles otherwise it sweeps through increasing angles

x - the absolute x coordinate of the final point of the arc.

y - the absolute y coordinate of the final point of the arc.

toPolygonArray

public java.awt.geom.Point2D.Double[] toPolygonArray()

Creates a polygon/polyline array of the bezier path which only includes the C0 control points of the bezier nodes.

If the bezier path is closed, the array describes a polygon. If the bezier path is open, the array describes a polyline.

Returns:

Point array.

setWindingRule

public void setWindingRule(int newValue)

Sets winding rule for filling the bezier path.

Parameters:

newValue - Must be Path2D.Double.WIND_EVEN_ODD or Path2D.Double.WIND_NON_ZERO.

getWindingRule

public int getWindingRule()

Gets winding rule for filling the bezier path.

Returns:

Path2D.Double.WIND_EVEN_ODD or Path2D.Double.WIND_NON_ZERO.