Class QuadCurve2D

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.

Constructors

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.

Since:

1.2

See Also:

QuadCurve2D.Float, QuadCurve2D.Double

Methods

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.

Since:

1.2

getY1

public abstract double getY1()

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

Returns:

the Y coordinate of the start point.

Since:

1.2

getP1

public abstract Point2D getP1()

Returns the start point.

Returns:

a Point2D that is the start point of this QuadCurve2D.

Since:

1.2

getCtrlX

public abstract double getCtrlX()

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

Returns:

X coordinate the control point

Since:

1.2

getCtrlY

public abstract double getCtrlY()

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

Returns:

the Y coordinate of the control point.

Since:

1.2

getCtrlPt

public abstract Point2D getCtrlPt()

Returns the control point.

Returns:

a Point2D that is the control point of this Point2D.

Since:

1.2

getX2

public abstract double getX2()

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

Returns:

the x coordinate of the end point.

Since:

1.2

getY2

public abstract double getY2()

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

Returns:

the Y coordinate of the end point.

Since:

1.2

getP2

public abstract Point2D getP2()

Returns the end point.

Returns:

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

Since:

1.2

setCurve

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

Sets the location of the end points and control point of this curve to the specified double coordinates.

Parameters:

x1 - the X coordinate of the start point

y1 - the Y coordinate of the start point

ctrlx - the X coordinate of the control point

ctrly - the Y coordinate of the control point

x2 - the X coordinate of the end point

y2 - the Y coordinate of the end point

Since:

1.2

setCurve

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

Sets the location of the end points and control points 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

Since:

1.2

setCurve

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

Sets the location of the end points and control point of this QuadCurve2D to the specified Point2D coordinates.

Parameters:

p1 - the start point

cp - the control point

p2 - the end point

Since:

1.2

setCurve

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

Sets the location of the end points and control points 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 from which to start getting the coordinate values and assigning them to this QuadCurve2D

Since:

1.2

setCurve

public void setCurve(QuadCurve2D c)

Sets the location of the end points and control point of this QuadCurve2D to the same as those in the specified QuadCurve2D.

Parameters:

c - the specified QuadCurve2D

Since:

1.2

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 control point from the line connecting the end points, of the quadratic curve specified by the indicated control points.

Parameters:

x1 - the X coordinate of the start point

y1 - the Y coordinate of the start point

ctrlx - the X coordinate of the control point

ctrly - the Y coordinate of the control point

x2 - the X coordinate of the end point

y2 - the Y coordinate of the end point

Returns:

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

Since:

1.2

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 control point from the line connecting the end points, of the quadratic curve specified by the indicated control points.

Parameters:

x1 - the X coordinate of the start point

y1 - the Y coordinate of the start point

ctrlx - the X coordinate of the control point

ctrly - the Y coordinate of the control point

x2 - the X coordinate of the end point

y2 - the Y coordinate of the end point

Returns:

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

Since:

1.2

getFlatnessSq

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

Returns the square of the flatness, or maximum distance of a control point from the line connecting the end points, of the quadratic curve specified by the control points stored in the indicated array at the indicated index.

Parameters:

coords - an array containing coordinate values

offset - the index into coords from which to to start getting the values from the array

Returns:

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

Since:

1.2

getFlatness

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

Returns the flatness, or maximum distance of a control point from the line connecting the end points, of the quadratic curve specified by the control points stored in the indicated array at the indicated index.

Parameters:

coords - an array containing coordinate values

offset - the index into coords from which to start getting the coordinate values

Returns:

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

Since:

1.2

getFlatnessSq

public double getFlatnessSq()

Returns the square of the flatness, or maximum distance of a control point from the line connecting the end points, of this QuadCurve2D.

Returns:

the square of the flatness of this QuadCurve2D.

Since:

1.2

getFlatness

public double getFlatness()

Returns the flatness, or maximum distance of a control point from the line connecting the end points, of this QuadCurve2D.

Returns:

the flatness of this QuadCurve2D.

Since:

1.2

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

Since:

1.2

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

Since:

1.2

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

Since:

1.2

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

Since:

1.2

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.

Since:

1.3

contains

public boolean contains(double x,
                        double y)

Tests if the specified coordinates are inside the boundary of the Shape, as described by the definition of insideness.

Specified by:

contains in interface Shape

Parameters:

x - the specified X coordinate to be tested

y - the specified Y coordinate to be tested

Returns:

true if the specified coordinates are inside the Shape boundary; false otherwise.

Since:

1.2

contains

public boolean contains(Point2D p)

Tests if a specified Point2D is inside the boundary of the Shape, as described by the definition of insideness.

Specified by:

contains in interface Shape

Parameters:

p - the specified Point2D to be tested

Returns:

true if the specified Point2D is inside the boundary of the Shape; false otherwise.

Since:

1.2

intersects

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

Specified by:

intersects in interface Shape

Parameters:

x - the X coordinate of the upper-left corner of the specified rectangular area

y - the Y coordinate of the upper-left corner of the specified rectangular area

w - the width of the specified rectangular area

h - the height of the specified rectangular area

Returns:

true if the interior of the Shape and the interior of the rectangular area intersect, or are both highly likely to intersect and intersection calculations would be too expensive to perform; false otherwise.

Since:

1.2

See Also:

Area

intersects

public boolean intersects(Rectangle2D r)

Tests if the interior of the Shape intersects the interior of a specified Rectangle2D. The Shape.intersects() method allows a Shape implementation to conservatively return true when:

• there is a high probability that the Rectangle2D and the Shape intersect, but
• the calculations to accurately determine this intersection are prohibitively expensive.

This means that for some Shapes this method might return true even though the Rectangle2D does not intersect the Shape. The Area class performs more accurate computations of geometric intersection than most Shape objects and therefore can be used if a more precise answer is required.

Specified by:

intersects in interface Shape

Parameters:

r - the specified Rectangle2D

Returns:

true if the interior of the Shape and the interior of the specified Rectangle2D intersect, or are both highly likely to intersect and intersection calculations would be too expensive to perform; false otherwise.

Since:

1.2

See Also:

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

contains

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

Specified by:

contains in interface Shape

Parameters:

x - the X coordinate of the upper-left corner of the specified rectangular area

y - the Y coordinate of the upper-left corner of the specified rectangular area

w - the width of the specified rectangular area

h - the height of the specified rectangular area

Returns:

true if the interior of the Shape entirely contains the specified rectangular area; false otherwise or, if the Shape contains the rectangular area and the intersects method returns true and the containment calculations would be too expensive to perform.

Since:

1.2

See Also:

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

contains

public boolean contains(Rectangle2D r)

Tests if the interior of the Shape entirely contains the specified Rectangle2D. The Shape.contains() method allows a Shape implementation to conservatively return false when:

• the intersect method returns true and
• the calculations to determine whether or not the Shape entirely contains the Rectangle2D are prohibitively expensive.

This means that for some Shapes this method might return false even though the Shape contains the Rectangle2D. The Area class performs more accurate geometric computations than most Shape objects and therefore can be used if a more precise answer is required.

Specified by:

contains in interface Shape

Parameters:

r - The specified Rectangle2D

Returns:

true if the interior of the Shape entirely contains the Rectangle2D; false otherwise or, if the Shape contains the Rectangle2D and the intersects method returns true and the containment calculations would be too expensive to perform.

Since:

1.2

See Also:

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

getBounds

public Rectangle getBounds()

Specified by:

getBounds in interface Shape

Returns:

an integer Rectangle that completely encloses the Shape.

Since:

1.2

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.

Since:

1.2

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 end points of this curve before this curve is replaced by a straight line connecting the end points.

Returns:

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

Since:

1.2

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