Package org.opentrafficsim.base.geometry

Class FractionalProjectionHelper

java.lang.Object

org.opentrafficsim.base.geometry.FractionalProjectionHelper

public final class FractionalProjectionHelper
extends Object

Fractional projection helper for OtsLine2d.

Copyright (c) 2026-2026 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
BSD-style license. See OpenTrafficSim License.

Author:

Wouter Schakel

See Also:

• OtsLine2d.projectFractionalAt(org.djunits.value.vdouble.scalar.Direction, org.djunits.value.vdouble.scalar.Direction, double, double, org.opentrafficsim.base.geometry.FractionalProjectionHelper.FractionalFallback)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	FractionalProjectionHelper.DirectionKey	Cache key for directions (normalized angles; nulls allowed).
static enum	FractionalProjectionHelper.FractionalFallback	Fallback strategies for when fractional projection is not applicable.
static final record	FractionalProjectionHelper.Helper	Value object: per-segment helper, either center or direction.

Method Summary

Modifier and Type	Method	Description
FractionalProjectionHelper.Helper	helperAtVertex(int vertexIndex, org.djunits.value.vdouble.scalar.Direction start, org.djunits.value.vdouble.scalar.Direction end)	Get the helper (center or direction) at a vertex index using (start,end) dependent edges.
double	projectFractionalAt(org.djunits.value.vdouble.scalar.Direction start, org.djunits.value.vdouble.scalar.Direction end, double x, double y, FractionalProjectionHelper.FractionalFallback fallback)	Fractionally project a point on the polyline using the fractional helper logic.

Methods inherited from class java.lang.Object

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

Method Details

projectFractionalAt

public double projectFractionalAt(org.djunits.value.vdouble.scalar.Direction start,
 org.djunits.value.vdouble.scalar.Direction end,
 double x,
 double y,
 FractionalProjectionHelper.FractionalFallback fallback)

Fractionally project a point on the polyline using the fractional helper logic. Falls back via the given strategy when fractional projection is not applicable.

Parameters:

start - direction in first point

end - direction in last point

x - x-coordinate of point to project

y - y-coordinate of point to project

fallback - fallback method for when fractional projection fails

Returns:

fractional position along this line of the fractional projection on that line of a point

See Also:

• OtsLine2d.projectFractionalAt(org.djunits.value.vdouble.scalar.Direction, org.djunits.value.vdouble.scalar.Direction, double, double, org.opentrafficsim.base.geometry.FractionalProjectionHelper.FractionalFallback)

helperAtVertex

public FractionalProjectionHelper.Helper helperAtVertex(int vertexIndex,
 org.djunits.value.vdouble.scalar.Direction start,
 org.djunits.value.vdouble.scalar.Direction end)

Get the helper (center or direction) at a vertex index using (start,end) dependent edges. Useful for curvature / radius logic. Supply (null, null) if that is the desired configuration.

Parameters:

vertexIndex - 0 .. size-1

start - direction at start (can be null)

end - direction at end (can be null)

Returns:

helper