Package net.paulhertz.pixelaudio.curves

Class PAGestureParametric

java.lang.Object

net.paulhertz.pixelaudio.curves.PAGestureParametric

public final class PAGestureParametric
extends Object

Treats a gesture defined by (time, x, y) samples as a parametric curve.

    u ∈ [0,1] → (t(u), x(u), y(u))
 

Under the hood:

• timesMs: int[] of time offsets (ms), ascending, timesMs[0] == 0
• points: PVector list (x,y) of same length

You can:

• sample with a linear parameter: f(u) = u
• pass a warp function f(u) to speed up/slow down traversal

Exponential warp (speeding up over time)

    DoubleUnaryOperator expWarp = u -> (float_ Math.pow(u, 2.0);   // u squared
    GestureParametric.Sample s = gp.sample(0.5f, expWarp);
 

Log-like warp (fast at start, slow at end)

    DoubleUnaryOperator sqrtWarp = u -> (float_ Math.sqrt(u);     // square root of u
    GestureParametric.Sample s = gp.sample(0.5f, sqrtWarp);
 

Something like f(u) = (e^{k * u} - 1) / (e^{k} - 1) for more dramatic warps.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	PAGestureParametric.Sample	Data storage class for PAGestureParametric.

Field Summary

Fields

Modifier and Type	Field	Description
private final int	count
private final List<processing.core.PVector>	points
private final int[]	timesMs
private final float	totalDurationMs

Constructor Summary

Constructors

Constructor	Description
PAGestureParametric(List<processing.core.PVector> points, int[] timesMs)

Method Summary

Modifier and Type	Method	Description
private int	findSegment(float tTarget)	Find the largest i such that timesMs[i] <= tTarget.
float	getTotalDurationMs()	Total gesture duration in ms.
private static float	lerp(float a, float b, float u)
PAGestureParametric.Sample	sample(float u)	Sample with linear parameterization: f(u) = u.
PAGestureParametric.Sample	sample(float u, DoubleUnaryOperator warp)	Sample with an optional warp function f(u) → [0,1].

Methods inherited from class java.lang.Object

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

Field Details

points

private final List<processing.core.PVector> points

timesMs

private final int[] timesMs

count

private final int count

totalDurationMs

private final float totalDurationMs

Constructor Details

PAGestureParametric

public PAGestureParametric(List<processing.core.PVector> points,
 int[] timesMs)

Parameters:

points - gesture points (x,y)

timesMs - time offsets (ms), same length as points, ascending, timesMs[0] == 0

Method Details

getTotalDurationMs

public float getTotalDurationMs()

Total gesture duration in ms.

sample

public PAGestureParametric.Sample sample(float u)

Sample with linear parameterization: f(u) = u. u is clamped to [0,1].

sample

public PAGestureParametric.Sample sample(float u,
 DoubleUnaryOperator warp)

Sample with an optional warp function f(u) → [0,1]. If warp is null, identity is used.

findSegment

private int findSegment(float tTarget)

Find the largest i such that timesMs[i] <= tTarget. Returns count-1 if tTarget is beyond the last sample.

lerp

private static float lerp(float a,
 float b,
 float u)