com.caffeineowl.graphics.bezier.flatnessalgos

Class LineDefectFlatnessAlgo

java.lang.Object

com.caffeineowl.graphics.bezier.flatnessalgos.LineDefectFlatnessAlgo

All Implemented Interfaces:

CubicFlatnessAlgorithm, QuadFlatnessAlgorithm

Direct Known Subclasses:

LineDefectSubdivCriterion

public class LineDefectFlatnessAlgo
extends Object
implements CubicFlatnessAlgorithm, QuadFlatnessAlgorithm

The algorithm computes the defected as the distance between the actual location control point(s) and the location of the control point(s) of a totally degenerated Bezier segment:

• for a quadratic Bezier, that's the mid point of the segment connecting the anchor points,
• for a totally degenerated cubic, the locations of the control points are at 1/3 and 2/3 positions of the segment that connects the anchor points.

Note that, while this algorithm is the least computational intensive, it applies the most strict flatness criterion: the Bezier segment needs to be close to the total degeneration to offer a good flatness.

Author:

Adrian Colomitchi (acolomitchi(monkey_tail)gmail.com)

Field Summary

Fields

Modifier and Type	Field and Description
static int	CBSV_DIST Use the Chebyshev (chess-board) distance to compute the distance between two points
protected int	distType The distance to use in computing the flatness.
static int	EUCL_DIST Use the Euclidian norm to compute the distance between two points
static int	MNHT_DIST Use the Manhattan (taxi-cab) distance to compute the distance between two points
protected boolean	usingSum Relevant only if this flatness algo is applied for the cubic: when true, the flatness is returned as the sum of the distances between the control points and their ideal position of the degenerate cubic.

Constructor Summary

Constructors

Constructor and Description
LineDefectFlatnessAlgo() Defaults to LineDefectFlatnessAlgo(int, boolean), with a EUCL_DIST for the distance type and using the sum for the case of cubics.
LineDefectFlatnessAlgo(boolean useSumation) Defaults to LineDefectFlatnessAlgo(int, boolean), with a EUCL_DIST for the distance type and using the specified behaviour for the use of sum/max when computing the flatness for cubics.
LineDefectFlatnessAlgo(int distType) Defaults to LineDefectFlatnessAlgo(int, boolean), with the specified distance type and using the sum for the case of cubics.
LineDefectFlatnessAlgo(int distType, boolean useSum) Initialised this instance with the specified distance type and summation behaviour.

Method Summary

Methods

Modifier and Type	Method and Description
double	getFlatness(CubicCurve2D curve) Computes the flatness of the cubic using the distance type and sum/max strategy used in initialisation.
double	getFlatness(QuadCurve2D curve) Computes the flatness of the quad curve using the distance type and sum/max strategy used in initialisation.
double	getSquaredFlatness(CubicCurve2D curve) Computes the squared flatness of the cubic using the distance type and sum/max strategy used in initialisation.
double	getSquaredFlatness(QuadCurve2D curve) Computes the squared flatness of the quad curve using the distance type and sum/max strategy used in initialisation.
boolean	isDegenerationRobust() Yes, works fine for degenerated curves (curves on which the control point(s) are on the line defined by its anchors).
boolean	isSquaredFlatenessPreferred() Returns true if the distance type is EUCL_DIST (since computing the squared distance is less computational expensive than computing the distance), false if the distance type is MNHT_DIST or CBSV_DIST (for those two, computing the distance is less computational expensive than computing the squared distance}.

Methods inherited from class java.lang.Object

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

Field Detail

EUCL_DIST

public static final int EUCL_DIST

Use the Euclidian norm to compute the distance between two points

See Also:

Constant Field Values

MNHT_DIST

public static final int MNHT_DIST

Use the Manhattan (taxi-cab) distance to compute the distance between two points

See Also:

Constant Field Values

CBSV_DIST

public static final int CBSV_DIST

Use the Chebyshev (chess-board) distance to compute the distance between two points

See Also:

Constant Field Values

distType

protected int distType

The distance to use in computing the flatness. Must be one of EUCL_DIST, MNHT_DIST or CBSV_DIST.

usingSum

protected boolean usingSum

Relevant only if this flatness algo is applied for the cubic: when true, the flatness is returned as the sum of the distances between the control points and their ideal position of the degenerate cubic. If false, the maximum of the two is returned as the flatness.

Constructor Detail

LineDefectFlatnessAlgo

public LineDefectFlatnessAlgo()

Defaults to LineDefectFlatnessAlgo(int, boolean), with a EUCL_DIST for the distance type and using the sum for the case of cubics.

LineDefectFlatnessAlgo

public LineDefectFlatnessAlgo(int distType)

Defaults to LineDefectFlatnessAlgo(int, boolean), with the specified distance type and using the sum for the case of cubics.

LineDefectFlatnessAlgo

public LineDefectFlatnessAlgo(boolean useSumation)

Defaults to LineDefectFlatnessAlgo(int, boolean), with a EUCL_DIST for the distance type and using the specified behaviour for the use of sum/max when computing the flatness for cubics.

LineDefectFlatnessAlgo

public LineDefectFlatnessAlgo(int distType,
                      boolean useSum)

Initialised this instance with the specified distance type and summation behaviour.

Parameters:

distType - the distance type. Must be one of EUCL_DIST, MNHT_DIST or CBSV_DIST. If it is not, the EUCL_DIST will be used.

useSum - sum-or-max strategy to be used when computing the flatness of a cubic.

Method Detail

isDegenerationRobust

public final boolean isDegenerationRobust()

Yes, works fine for degenerated curves (curves on which the control point(s) are on the line defined by its anchors).

Specified by:

isDegenerationRobust in interface CubicFlatnessAlgorithm

Specified by:

isDegenerationRobust in interface QuadFlatnessAlgorithm

isSquaredFlatenessPreferred

public final boolean isSquaredFlatenessPreferred()

Returns true if the distance type is EUCL_DIST (since computing the squared distance is less computational expensive than computing the distance), false if the distance type is MNHT_DIST or CBSV_DIST (for those two, computing the distance is less computational expensive than computing the squared distance}.

Specified by:

isSquaredFlatenessPreferred in interface CubicFlatnessAlgorithm

Specified by:

isSquaredFlatenessPreferred in interface QuadFlatnessAlgorithm

getFlatness

public final double getFlatness(CubicCurve2D curve)

Computes the flatness of the cubic using the distance type and sum/max strategy used in initialisation. The flatness (actually the defect of the flatness - the higher, the worse) is computed based on the distance between the control points of the provided curve and the "ideal" positions (at 1/3 and 2/3 on the segment defined by the control points).

Specified by:

getFlatness in interface CubicFlatnessAlgorithm

getSquaredFlatness

public final double getSquaredFlatness(CubicCurve2D curve)

Computes the squared flatness of the cubic using the distance type and sum/max strategy used in initialisation. The flatness (actually the defect of the flatness - the higher, the worse) is computed based on the distance between the control points of the provided curve and the "ideal" positions (at 1/3 and 2/3 on the segment defined by the control points).

Specified by:

getSquaredFlatness in interface CubicFlatnessAlgorithm

getFlatness

public final double getFlatness(QuadCurve2D curve)

Computes the flatness of the quad curve using the distance type and sum/max strategy used in initialisation. The flatness (actually the defect of the flatness - the higher, the worse) is computed based on the distance between the control point of the provided curve and the "ideal" position (the mid point on the segment defined by the control points).

Specified by:

getFlatness in interface QuadFlatnessAlgorithm

getSquaredFlatness

public final double getSquaredFlatness(QuadCurve2D curve)

Computes the squared flatness of the quad curve using the distance type and sum/max strategy used in initialisation. The flatness (actually the defect of the flatness - the higher, the worse) is computed based on the distance between the control point of the provided curve and the "ideal" position (the mid point on the segment defined by the control points).

Specified by:

getSquaredFlatness in interface QuadFlatnessAlgorithm