org.eclipse.gef4.geometry.planar

Class BezierCurve.Interval

java.lang.Object

org.eclipse.gef4.geometry.planar.BezierCurve.Interval

Enclosing class:

BezierCurve

public static final class BezierCurve.Interval
extends java.lang.Object

An BezierCurve.Interval records a lower and an upper limit that define the mathematical interval [a;b] (inclusively). It is used to represent sub-curves of a BezierCurve by bounding the BezierCurve's parameter value to the respective interval.

Field Summary

Fields

Modifier and Type	Field and Description
double	a An BezierCurve.Interval records the parameter range [a;b].
double	b An BezierCurve.Interval records the parameter range [a;b].

Constructor Summary

Constructors

Constructor and Description
Interval(double... ds) Constructs a new BezierCurve.Interval object from the given double values.

Method Summary

Modifier and Type	Method and Description
boolean	converges() Checks if this BezierCurve.Interval's parameter range does converge with default imprecision.
boolean	converges(int shift) Checks if this BezierCurve.Interval's parameter range does converge with specified imprecision.
void	expand(BezierCurve.Interval i) Expands this BezierCurve.Interval to include the given other BezierCurve.Interval.
BezierCurve.Interval	getCopy() Returns a copy of this BezierCurve.Interval.
static BezierCurve.Interval	getEmpty() Constructs a new BezierCurve.Interval object holding an invalid parameter interval.
static BezierCurve.Interval	getFull() Constructs a new BezierCurve.Interval object holding the interval [0;1] which is the parameter BezierCurve.Interval representing a full BezierCurve.
double	getMid() Returns the middle parameter value m = (a+b)/2 of this BezierCurve.Interval.
static BezierCurve.Interval	min(BezierCurve.Interval i, BezierCurve.Interval j) Returns the smaller BezierCurve.Interval object, i.e. the one with the smallest parameter range.
double	scaleTo(BezierCurve.Interval interval) Scales this BezierCurve.Interval to the given BezierCurve.Interval.

Methods inherited from class java.lang.Object

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

Field Detail

a

public double a

An BezierCurve.Interval records the parameter range [a;b]. Valid parameter ranges require 0 <= a <= b <= 1.

b

public double b

An BezierCurve.Interval records the parameter range [a;b]. Valid parameter ranges require 0 <= a <= b <= 1.

Constructor Detail

Interval

public Interval(double... ds)

Constructs a new BezierCurve.Interval object from the given double values. Only the first two double values are of importance as the rest of them are ignored.

The new BezierCurve.Interval holds the parameter range [a;b] if a is the first double value and b is the second double value.

Parameters:

ds - the lower and upper limit for the BezierCurve.Interval object to be created

Method Detail

getEmpty

public static BezierCurve.Interval getEmpty()

Constructs a new BezierCurve.Interval object holding an invalid parameter interval.

Returns:

a new BezierCurve.Interval object holding an invalid parameter interval

getFull

public static BezierCurve.Interval getFull()

Constructs a new BezierCurve.Interval object holding the interval [0;1] which is the parameter BezierCurve.Interval representing a full BezierCurve.

Returns:

a new BezierCurve.Interval object holding the interval [0;1]

min

public static BezierCurve.Interval min(BezierCurve.Interval i,
                                       BezierCurve.Interval j)

Returns the smaller BezierCurve.Interval object, i.e. the one with the smallest parameter range.

Parameters:

i - The first operand.

j - The second operand.

Returns:

The BezierCurve.Interval with the smallest parameter range.

converges

public boolean converges()

Checks if this BezierCurve.Interval's parameter range does converge with default imprecision.

Returns:

true if a ~= b (within default imprecision), otherwise false

See Also:

converges(int)

converges

public boolean converges(int shift)

Checks if this BezierCurve.Interval's parameter range does converge with specified imprecision.

The imprecision is specified by providing a shift value which shifts the epsilon used for the number comparison. A positive shift demands for a smaller epsilon (higher precision) whereas a negative shift demands for a greater epsilon (lower precision).

Parameters:

shift - precision shift

Returns:

true if a ~= b (within specified imprecision), otherwise false

expand

public void expand(BezierCurve.Interval i)

Expands this BezierCurve.Interval to include the given other BezierCurve.Interval.

Parameters:

i - The other BezierCurve.Interval to which this is expanded.

getCopy

public BezierCurve.Interval getCopy()

Returns a copy of this BezierCurve.Interval.

Returns:

a copy of this BezierCurve.Interval

getMid

public double getMid()

Returns the middle parameter value m = (a+b)/2 of this BezierCurve.Interval.

Returns:

the middle parameter value of this BezierCurve.Interval

scaleTo

public double scaleTo(BezierCurve.Interval interval)

Scales this BezierCurve.Interval to the given BezierCurve.Interval. The given BezierCurve.Interval specifies the new upper and lower bounds of this BezierCurve.Interval in percent.

Returns the ratio of this BezierCurve.Interval's new parameter range to its old parameter range.

Parameters:

interval - the new upper and lower bounds in percent

Returns:

the ratio of this BezierCurve.Interval's new parameter range to its old parameter range