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

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

A BezierPath represents a geometric path constructed by vertices. Each Node has three control points: C0, C1, C2. A mask defines which control points are in use. The path passes through C0. C1 controls the curve going towards C0. C2 controls the curve going away from C0.

Version:

1.3 BezierPath has now its own BezierPathIterator.
1.2.1 Issue #1628647: Method splitSegment created incorrect control point masks.
1.2 2006-12-09 Method setWindingRule added.
1.1 2006-03-22 Methods moveTo, lineTo and quadTo added.
1.0 January 20, 2006 Created.

Author:

Werner Randelshofer

See Also:

Serialized Form

Nested Class Summary

static class

BezierPath.Node Defines a vertex (node) of the bezier path.

Field Summary

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).

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

BezierPath()
Creates a new instance.

Method Summary

void	add(int mask, java.awt.geom.Point2D.Double c0, java.awt.geom.Point2D.Double c1, java.awt.geom.Point2D.Double c2) Convenience method for adding a control point with three coordinates C0, C1 and C2 with a mask.
void	add(java.awt.geom.Point2D.Double c0) Convenience method for adding a control point with a single coordinate C0.
void	addPoint(double x, double y)
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)
int	findSegment(java.awt.geom.Point2D.Double find, float tolerance) Gets the segment of the polyline that is hit by the given Point2D.Double.
java.awt.geom.Point2D.Double	get(int index, int coord) Convenience method for getting a single coordinate of a control point.
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 control point that is furthest 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, float tolerance) Joins two segments into one if the given Point2D.Double hits a node of the bezier path.
void	lineTo(double x1, double y1)
void	moveTo(double x1, double y1)
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)
void	set(int index, int coord, java.awt.geom.Point2D.Double p) Convenience method for changing a single coordinate of a control point.
void	setClosed(boolean newValue)
void	setTo(BezierPath that)
void	setWindingRule(int newValue) Sets winding rule for filling the bezier path.
int	splitSegment(java.awt.geom.Point2D.Double split, float tolerance) Splits the segment at the given Point2D.Double if a segment was hit.
java.awt.geom.GeneralPath	toGeneralPath() Converts the BezierPath into a GeneralPath.
java.awt.geom.Point2D.Double[]	toPolygonArray()
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, get, indexOf, isEmpty, lastIndexOf, remove, remove, removeRange, set, size, toArray, toArray, trimToSize

Methods inherited from class java.util.AbstractList

equals, hashCode, iterator, listIterator, listIterator, subList

Methods inherited from class java.util.AbstractCollection

containsAll, removeAll, retainAll, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

containsAll, equals, hashCode, iterator, listIterator, listIterator, removeAll, retainAll, subList

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)

Convenience method for adding a control point with a single coordinate C0.

addPoint

public void addPoint(double x,
                     double y)

add

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

Convenience method for adding a control point with three coordinates C0, C1 and C2 with a mask.

set

public void set(int index,
                int coord,
                java.awt.geom.Point2D.Double p)

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

get

public java.awt.geom.Point2D.Double get(int index,
                                        int coord)

Convenience method for getting a single coordinate of a 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.GeneralPath toGeneralPath()

Converts the BezierPath into a GeneralPath.

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)

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 control point that is furthest from the center

getPointOnPath

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,
                       float 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,
                        float 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,
                        float 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)

lineTo

public void lineTo(double x1,
                   double y1)

quadTo

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

curveTo

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

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()

setWindingRule

public void setWindingRule(int newValue)

Sets winding rule for filling the bezier path.

Parameters:

newValue - Must be GeneralPath.WIND_EVEN_ODD or GeneralPath.WIND_NON_ZERO.

getWindingRule

public int getWindingRule()

Gets winding rule for filling the bezier path.

Returns:

GeneralPath.WIND_EVEN_ODD or GeneralPath.WIND_NON_ZERO.