java.awt.geom
Class QuadCurve2D

java.lang.Object
  java.awt.geom.QuadCurve2D

All Implemented Interfaces:

Cloneable, Shape

Direct Known Subclasses:

QuadCurve2D.Double, QuadCurve2D.Float

public abstract class QuadCurve2D

extends Object

implements Shape, Cloneable

The QuadCurve2D class defines a quadratic parametric curve segment in (x, y) coordinate space.

This class is only the abstract superclass for all objects that store a 2D quadratic curve segment. The actual storage representation of the coordinates is left to the subclass.

Author:

Jim Graham

Nested Class Summary

static class	QuadCurve2D.Double A quadratic parametric curve segment specified with double coordinates.
static class	QuadCurve2D.Float A quadratic parametric curve segment specified with float coordinates.

Field Summary

private static int	ABOVE
private static int	BELOW
private static int	HIGHEDGE
private static int	INSIDE
private static int	LOWEDGE

Constructor Summary

protected

QuadCurve2D() This is an abstract class that cannot be instantiated directly.

Method Summary

Object	clone() Creates a new object of the same class and with the same contents as this object.
boolean	contains(double x, double y) Tests if a specified coordinate is inside the boundary of the shape of this QuadCurve2D.
boolean	contains(double x, double y, double w, double h) Tests if the interior of the shape of this QuadCurve2D entirely contains the specified set of rectangular coordinates.
boolean	contains(Point2D p) Tests if a specified Point2D is inside the boundary of the shape of this QuadCurve2D.
boolean	contains(Rectangle2D r) Tests if the interior of the shape of this QuadCurve2D entirely contains the specified Rectangle2D.
private static int	evalQuadratic(double[] vals, int num, boolean include0, boolean include1, double[] inflect, double c1, double ctrl, double c2)
private static void	fillEqn(double[] eqn, double val, double c1, double cp, double c2)
Rectangle	getBounds() Returns the bounding box of this QuadCurve2D.
abstract Point2D	getCtrlPt() Returns the control point.
abstract double	getCtrlX() Returns the x coordinate of the control point in double precision.
abstract double	getCtrlY() Returns the y coordinate of the control point in double precision.
double	getFlatness() Returns the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of this QuadCurve2D.
static double	getFlatness(double[] coords, int offset) Returns the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of the quadratic curve specified by the controlpoints stored in the indicated array at the indicated index.
static double	getFlatness(double x1, double y1, double ctrlx, double ctrly, double x2, double y2) Returns the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of the quadratic curve specified by the indicated controlpoints.
double	getFlatnessSq() Returns the square of the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of this QuadCurve2D.
static double	getFlatnessSq(double[] coords, int offset) Returns the square of the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of the quadratic curve specified by the controlpoints stored in the indicated array at the indicated index.
static double	getFlatnessSq(double x1, double y1, double ctrlx, double ctrly, double x2, double y2) Returns the square of the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of the quadratic curve specified by the indicated controlpoints.
abstract Point2D	getP1() Returns the start point.
abstract Point2D	getP2() Returns the end point.
PathIterator	getPathIterator(AffineTransform at) Returns an iteration object that defines the boundary of the shape of this QuadCurve2D.
PathIterator	getPathIterator(AffineTransform at, double flatness) Returns an iteration object that defines the boundary of the flattened shape of this QuadCurve2D.
private static int	getTag(double coord, double low, double high)
abstract double	getX1() Returns the x coordinate of the start point in double in precision.
abstract double	getX2() Returns the x coordinate of the end point in double precision.
abstract double	getY1() Returns the y coordinate of the start point in double precision.
abstract double	getY2() Returns the y coordinate of the end point in double precision.
boolean	intersects(double x, double y, double w, double h) Tests if the shape of this QuadCurve2D intersects the interior of a specified set of rectangular coordinates.
boolean	intersects(Rectangle2D r) Tests if the shape of this QuadCurve2D intersects the interior of a specified Rectangle2D.
private static boolean	inwards(int pttag, int opt1tag, int opt2tag)
void	setCurve(double[] coords, int offset) Sets the location of the endpoints and controlpoints of this QuadCurve2D to the double coordinates at the specified offset in the specified array.
abstract void	setCurve(double x1, double y1, double ctrlx, double ctrly, double x2, double y2) Sets the location of the endpoints and controlpoint of this curve to the specified double coordinates.
void	setCurve(Point2D[] pts, int offset) Sets the location of the endpoints and controlpoints of this QuadCurve2D to the coordinates of the Point2D objects at the specified offset in the specified array.
void	setCurve(Point2D p1, Point2D cp, Point2D p2) Sets the location of the endpoints and controlpoint of this QuadCurve2D to the specified Point2D coordinates.
void	setCurve(QuadCurve2D c) Sets the location of the endpoints and controlpoint of this QuadCurve2D to the same as those in the specified QuadCurve2D.
static int	solveQuadratic(double[] eqn) Solves the quadratic whose coefficients are in the eqn array and places the non-complex roots back into the same array, returning the number of roots.
static int	solveQuadratic(double[] eqn, double[] res) Solves the quadratic whose coefficients are in the eqn array and places the non-complex roots into the res array, returning the number of roots.
static void	subdivide(double[] src, int srcoff, double[] left, int leftoff, double[] right, int rightoff) Subdivides the quadratic curve specified by the coordinates stored in the src array at indices srcoff through srcoff + 5 and stores the resulting two subdivided curves into the two result arrays at the corresponding indices.
void	subdivide(QuadCurve2D left, QuadCurve2D right) Subdivides this QuadCurve2D and stores the resulting two subdivided curves into the left and right curve parameters.
static void	subdivide(QuadCurve2D src, QuadCurve2D left, QuadCurve2D right) Subdivides the quadratic curve specified by the src parameter and stores the resulting two subdivided curves into the left and right curve parameters.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.awt.Shape

getBounds2D

Field Detail

BELOW

private static final int BELOW

See Also:

Constant Field Values

LOWEDGE

private static final int LOWEDGE

See Also:

Constant Field Values

INSIDE

private static final int INSIDE

See Also:

Constant Field Values

HIGHEDGE

private static final int HIGHEDGE

See Also:

Constant Field Values

ABOVE

private static final int ABOVE

See Also:

Constant Field Values

Constructor Detail

QuadCurve2D

protected QuadCurve2D()

This is an abstract class that cannot be instantiated directly. Type-specific implementation subclasses are available for instantiation and provide a number of formats for storing the information necessary to satisfy the various accessor methods below.

See Also:

QuadCurve2D.Float, QuadCurve2D.Double

Method Detail

getX1

public abstract double getX1()

Returns the x coordinate of the start point in double in precision.

Returns:

the x coordinate of the start point.

getY1

public abstract double getY1()

Returns the y coordinate of the start point in double precision.

Returns:

the y coordinate of the start point.

getP1

public abstract Point2D getP1()

Returns the start point.

Returns:

a Point2D that is the start point of this QuadCurve2D.

getCtrlX

public abstract double getCtrlX()

Returns the x coordinate of the control point in double precision.

Returns:

x coordinate the control point

getCtrlY

public abstract double getCtrlY()

Returns the y coordinate of the control point in double precision.

Returns:

the y coordinate of the control point.

getCtrlPt

public abstract Point2D getCtrlPt()

Returns the control point.

Returns:

a Point2D that is the control point of this Point2D.

getX2

public abstract double getX2()

Returns the x coordinate of the end point in double precision.

Returns:

the x coordiante of the end point.

getY2

public abstract double getY2()

Returns the y coordinate of the end point in double precision.

Returns:

the y coordinate of the end point.

getP2

public abstract Point2D getP2()

Returns the end point.

Returns:

a Point object that is the end point of this Point2D.

setCurve

public abstract void setCurve(double x1,
                              double y1,
                              double ctrlx,
                              double ctrly,
                              double x2,
                              double y2)

Sets the location of the endpoints and controlpoint of this curve to the specified double coordinates.

setCurve

public void setCurve(double[] coords,
                     int offset)

Sets the location of the endpoints and controlpoints of this QuadCurve2D to the double coordinates at the specified offset in the specified array.

Parameters:

coords - the array containing coordinate values

offset - the index into the array from which to start getting the coordinate values and assigning them to this QuadCurve2D

setCurve

public void setCurve(Point2D p1,
                     Point2D cp,
                     Point2D p2)

Sets the location of the endpoints and controlpoint of this QuadCurve2D to the specified Point2D coordinates.

Parameters:

p1 - the starting point

cp - the control point

p2 - the ending point

setCurve

public void setCurve(Point2D[] pts,
                     int offset)

Sets the location of the endpoints and controlpoints of this QuadCurve2D to the coordinates of the Point2D objects at the specified offset in the specified array.

Parameters:

pts - an array containing Point2D that define coordinate values

offset - the index into pts at which to start getting the coordinate values and assigning them to this QuadCurve2D

setCurve

public void setCurve(QuadCurve2D c)

Sets the location of the endpoints and controlpoint of this QuadCurve2D to the same as those in the specified QuadCurve2D.

Parameters:

c - the specified QuadCurve2D

getFlatnessSq

public static double getFlatnessSq(double x1,
                                   double y1,
                                   double ctrlx,
                                   double ctrly,
                                   double x2,
                                   double y2)

Returns the square of the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of the quadratic curve specified by the indicated controlpoints.

Returns:

the square of the flatness of the quadratic curve defined by the specified coordinates.

getFlatness

public static double getFlatness(double x1,
                                 double y1,
                                 double ctrlx,
                                 double ctrly,
                                 double x2,
                                 double y2)

Returns the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of the quadratic curve specified by the indicated controlpoints.

Returns:

the flatness of the quadratic curve defined by the specified coordinates.

getFlatnessSq

public static double getFlatnessSq(double[] coords,
                                   int offset)

Returns the square of the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of the quadratic curve specified by the controlpoints stored in the indicated array at the indicated index.

Parameters:

coords - an array containing coordinate values

offset - the index into coords at which to to start getting the values from the array and assigning them to a quadratic curve

Returns:

the flatness of the quadratic curve that is defined by the values in the specified array at the specified index.

getFlatness

public static double getFlatness(double[] coords,
                                 int offset)

Returns the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of the quadratic curve specified by the controlpoints stored in the indicated array at the indicated index.

Parameters:

coords - an array containing coordinate values

offset - the index into coords at which to start getting the coordinate values and assigning them to a quadratic curve

Returns:

the flatness of a quadratic curve defined by the specified array at the specified offset.

getFlatnessSq

public double getFlatnessSq()

Returns the square of the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of this QuadCurve2D.

Returns:

the square of the flatness of this QuadCurve2D.

getFlatness

public double getFlatness()

Returns the flatness, or maximum distance of a controlpoint from the line connecting the endpoints, of this QuadCurve2D.

Returns:

the flatness of this QuadCurve2D.

subdivide

public void subdivide(QuadCurve2D left,
                      QuadCurve2D right)

Subdivides this QuadCurve2D and stores the resulting two subdivided curves into the left and right curve parameters. Either or both of the left and right objects can be the same as this QuadCurve2D or null.

Parameters:

left - the QuadCurve2D object for storing the left or first half of the subdivided curve

right - the QuadCurve2D object for storing the right or second half of the subdivided curve

subdivide

public static void subdivide(QuadCurve2D src,
                             QuadCurve2D left,
                             QuadCurve2D right)

Subdivides the quadratic curve specified by the src parameter and stores the resulting two subdivided curves into the left and right curve parameters. Either or both of the left and right objects can be the same as the src object or null.

Parameters:

src - the quadratic curve to be subdivided

left - the QuadCurve2D object for storing the left or first half of the subdivided curve

right - the QuadCurve2D object for storing the right or second half of the subdivided curve

subdivide

public static void subdivide(double[] src,
                             int srcoff,
                             double[] left,
                             int leftoff,
                             double[] right,
                             int rightoff)

Subdivides the quadratic curve specified by the coordinates stored in the src array at indices srcoff through srcoff + 5 and stores the resulting two subdivided curves into the two result arrays at the corresponding indices. Either or both of the left and right arrays can be null or a reference to the same array and offset as the src array. Note that the last point in the first subdivided curve is the same as the first point in the second subdivided curve. Thus, it is possible to pass the same array for left and right and to use offsets such that rightoff equals leftoff + 4 in order to avoid allocating extra storage for this common point.

Parameters:

src - the array holding the coordinates for the source curve

srcoff - the offset into the array of the beginning of the the 6 source coordinates

left - the array for storing the coordinates for the first half of the subdivided curve

leftoff - the offset into the array of the beginning of the the 6 left coordinates

right - the array for storing the coordinates for the second half of the subdivided curve

rightoff - the offset into the array of the beginning of the the 6 right coordinates

solveQuadratic

public static int solveQuadratic(double[] eqn)

Solves the quadratic whose coefficients are in the eqn array and places the non-complex roots back into the same array, returning the number of roots. The quadratic solved is represented by the equation:

     eqn = {C, B, A};
     ax^2 + bx + c = 0
 

A return value of -1 is used to distinguish a constant equation, which might be always 0 or never 0, from an equation that has no zeroes.

Parameters:

eqn - the array that contains the quadratic coefficients

Returns:

the number of roots, or -1 if the equation is a constant

solveQuadratic

public static int solveQuadratic(double[] eqn,
                                 double[] res)

Solves the quadratic whose coefficients are in the eqn array and places the non-complex roots into the res array, returning the number of roots. The quadratic solved is represented by the equation:

     eqn = {C, B, A};
     ax^2 + bx + c = 0
 

A return value of -1 is used to distinguish a constant equation, which might be always 0 or never 0, from an equation that has no zeroes.

Parameters:

eqn - the specified array of coefficients to use to solve the quadratic equation

res - the array that contains the non-complex roots resulting from the solution of the quadratic equation

Returns:

the number of roots, or -1 if the equation is a constant.

contains

public boolean contains(double x,
                        double y)

Tests if a specified coordinate is inside the boundary of the shape of this QuadCurve2D.

Specified by:

contains in interface Shape

Parameters:

x - the specified x coordinate

y - the specified y coordinate

Returns:

true if the specified coordinate is inside the boundary of the shape of this QuadCurve2D; false otherwise.

contains

public boolean contains(Point2D p)

Tests if a specified Point2D is inside the boundary of the shape of this QuadCurve2D.

Specified by:

contains in interface Shape

Parameters:

p - the specified Point2D

Returns:

true if the specified Point2D is inside the boundary of the shape of this QuadCurve2D.

fillEqn

private static void fillEqn(double[] eqn,
                            double val,
                            double c1,
                            double cp,
                            double c2)

evalQuadratic

private static int evalQuadratic(double[] vals,
                                 int num,
                                 boolean include0,
                                 boolean include1,
                                 double[] inflect,
                                 double c1,
                                 double ctrl,
                                 double c2)

getTag

private static int getTag(double coord,
                          double low,
                          double high)

inwards

private static boolean inwards(int pttag,
                               int opt1tag,
                               int opt2tag)

intersects

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

Tests if the shape of this QuadCurve2D intersects the interior of a specified set of rectangular coordinates.

Specified by:

intersects in interface Shape

Parameters:

w - the width of the specified rectangular area

h - the height of the specified rectangular area

x - the x coordinate of the specified rectangular area

y - the y coordinate of the specified rectangular area

Returns:

true if the shape of this QuadCurve2D intersects the interior of the specified set of rectangular coordinates; false otherwise.

See Also:

Area

intersects

public boolean intersects(Rectangle2D r)

Tests if the shape of this QuadCurve2D intersects the interior of a specified Rectangle2D.

Specified by:

intersects in interface Shape

Parameters:

r - the specified Rectangle2D

Returns:

true if the shape of this QuadCurve2D intersects the interior of the specified Rectangle2D; false otherwise.

See Also:

Shape.intersects(double, double, double, double)

contains

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

Tests if the interior of the shape of this QuadCurve2D entirely contains the specified set of rectangular coordinates.

Specified by:

contains in interface Shape

Parameters:

w - the width of the specified rectangular area

h - the height of the specified rectangular area

x - the x coordinate of the specified rectangular area

y - the y coordinate of the specified rectangular area

Returns:

true if the interior of the shape of this QuadCurve2D entirely contains the specified rectangluar area; false otherwise.

See Also:

Area, Shape.intersects(double, double, double, double)

contains

public boolean contains(Rectangle2D r)

Tests if the interior of the shape of this QuadCurve2D entirely contains the specified Rectangle2D.

Specified by:

contains in interface Shape

Parameters:

r - the specified Rectangle2D

Returns:

true if the interior of the shape of this QuadCurve2D entirely contains the specified Rectangle2D; false otherwise.

See Also:

Shape.contains(double, double, double, double)

getBounds

public Rectangle getBounds()

Returns the bounding box of this QuadCurve2D.

Specified by:

getBounds in interface Shape

Returns:

a Rectangle that is the bounding box of the shape of this QuadCurve2D.

See Also:

Shape.getBounds2D()

getPathIterator

public PathIterator getPathIterator(AffineTransform at)

Returns an iteration object that defines the boundary of the shape of this QuadCurve2D. The iterator for this class is not multi-threaded safe, which means that this QuadCurve2D class does not guarantee that modifications to the geometry of this QuadCurve2D object do not affect any iterations of that geometry that are already in process.

Specified by:

getPathIterator in interface Shape

Parameters:

at - an optional AffineTransform to apply to the shape boundary

Returns:

a PathIterator object that defines the boundary of the shape.

getPathIterator

public PathIterator getPathIterator(AffineTransform at,
                                    double flatness)

Returns an iteration object that defines the boundary of the flattened shape of this QuadCurve2D. The iterator for this class is not multi-threaded safe, which means that this QuadCurve2D class does not guarantee that modifications to the geometry of this QuadCurve2D object do not affect any iterations of that geometry that are already in process.

Specified by:

getPathIterator in interface Shape

Parameters:

at - an optional AffineTransform to apply to the boundary of the shape

flatness - the maximum distance that the control points for a subdivided curve can be with respect to a line connecting the endpoints of this curve before this curve is replaced by a straight line connecting the endpoints.

Returns:

a PathIterator object that defines the flattened boundary of the shape.

clone

public Object clone()

Creates a new object of the same class and with the same contents as this object.

Overrides:

clone in class Object

Returns:

a clone of this instance.

Throws:

OutOfMemoryError - if there is not enough memory.

Since:

1.2

See Also:

Cloneable