Enum EaseType

Identifies the easing algorithm applied to a tween's normalized time value during interpolation. Each value maps to a corresponding static method on Ease and controls the rate of change of the animated property over the tween's duration.

Easing types follow the standard naming convention popularised by Robert Penner:

• In variants accelerate from zero velocity - slow at the start.
• Out variants decelerate toward zero velocity - slow at the end.
• InOut variants combine both - slow at the start and at the end.

Some easing types (Elastic, Back) intentionally produce values outside the [0, 1] range. The interpolation functions in TweenLerp use unclamped arithmetic to preserve these overshoots correctly.

The special value Custom is a sentinel that signals the tween engine to use a user-supplied delegate rather than a named curve. It is set automatically when ITween.SetEase(Func<float, float>) is called and should not normally be assigned directly.

Namespace: Scylla.Core.Util.Tween

Assembly: ScyllaCore.dll

Syntax

public enum EaseType

Fields

Name	Description
Custom	Sentinel value indicating that a user-supplied easing delegate is active. This value is set automatically by ITween.SetEase(Func<float, float>) and should not be assigned directly via ITween.SetEase(EaseType). When the tween engine encounters this value it invokes the stored delegate instead of dispatching through Evaluate(EaseType, float).
Flash	A non-standard flash curve that ramps linearly from 0 to 1 during the first half of the duration and then ramps back down from 1 to 0 during the second half. Useful for brief visibility pulses or highlight effects.
InBack	Back easing that begins with an anticipation phase - the property moves slightly in the opposite direction before accelerating toward the end value. The overshoot amount is controlled by the constant BACK_S = 1.70158 inside Ease. Output goes slightly below 0 before rising to 1.
InBounce	Bounce easing that simulates a ball thrown against the starting point - the property bounces multiple times before settling into the start of its forward motion. Implemented as the inverse of OutBounce. Output stays within [0, 1].
InCirc	Circular easing based on the equation of a circle that begins slowly and accelerates steeply toward the end. Formula: f(t) = 1 - √(1 - t²). The curve has infinite slope at t = 1, giving a sharp arrival.
InCubic	Cubic easing (power of 3) that begins slowly and accelerates strongly toward the end. Formula: f(t) = t³. More pronounced acceleration than InQuad.
InElastic	Elastic easing that simulates a spring-like overshoot at the start of the animation. The property oscillates before settling into the end value. The oscillation magnitude and frequency are controlled by the constants ELASTIC_P (period) and ELASTIC_A (amplitude) inside Ease. Output can exceed [0, 1].
InExpo	Exponential easing (base-2 power curve) that begins nearly motionless and accelerates explosively toward the end. Formula: f(t) = 2^(10*(t-1)). Clamped to exactly 0 at t = 0 and 1 at t = 1 to avoid floating-point asymptotes.
InOutBack	Back easing that combines anticipation at the start and overshoot at the end. Uses a larger overshoot constant (BACK_S2 = BACK_S * 1.525) to maintain visual balance in the combined curve. Output goes outside [0, 1] at both ends.
InOutBounce	Bounce easing that applies bouncing at both the start and the end of the animation. The first half mirrors InBounce and the second half mirrors OutBounce. Output stays within [0, 1].
InOutCirc	Circular easing that begins steeply, transitions smoothly through the midpoint, and ends steeply with a sharp deceleration. Produces the most S-shaped InOut curve.
InOutCubic	Cubic easing (power of 3) that begins slowly, peaks at the midpoint, and decelerates symmetrically toward the end. More pronounced curvature than InOutQuad.
InOutElastic	Elastic easing that combines oscillation at both the start and the end of the animation. Output can significantly exceed [0, 1]. Use with unclamped interpolation methods such as those in TweenLerp.
InOutExpo	Exponential easing (base-2 power curve) that begins nearly motionless, accelerates explosively through the midpoint, and decelerates nearly to a stop at the end. Clamped to exactly 0 and 1 at the boundary values.
InOutQuad	Quadratic easing (power of 2) that begins slowly, peaks at the midpoint, and decelerates symmetrically toward the end. A smooth, natural-feeling curve well-suited to camera moves and object repositioning.
InOutQuart	Quartic easing (power of 4) that begins slowly, peaks sharply at the midpoint, and decelerates symmetrically toward the end. One of the more aggressive InOut curves.
InOutQuint	Quintic easing (power of 5) that begins slowly, peaks sharply at the midpoint, and decelerates symmetrically toward the end. The most aggressive of the polynomial InOut types.
InOutSine	Sinusoidal easing that begins slowly, reaches full speed at the midpoint, and decelerates symmetrically toward the end. Formula: f(t) = -0.5 * (cos(π * t) - 1).
InQuad	Quadratic easing (power of 2) that begins slowly and accelerates toward the end. Formula: f(t) = t². A good general-purpose ease-in with moderate acceleration.
InQuart	Quartic easing (power of 4) that begins slowly and accelerates very strongly toward the end. Formula: f(t) = t⁴. Creates a dramatic slow-start effect followed by a sharp rush to the finish.
InQuint	Quintic easing (power of 5) that begins slowly and accelerates extremely strongly toward the end. Formula: f(t) = t⁵. The most aggressive of the polynomial ease-in types.
InSine	Sinusoidal easing that begins slowly and accelerates toward the end, following the shape of a cosine curve: f(t) = 1 - cos(t * π/2). Produces the gentlest acceleration of all the power-curve variants.
Linear	No easing - the animated property advances at a perfectly constant rate. The output equals the input: f(t) = t. Use this when you want mechanical, clock-like motion with no acceleration or deceleration.
OutBack	Back easing that overshoots the end value and then settles back. The property exceeds 1 before decelerating back to exactly 1. Overshoot amount is controlled by BACK_S = 1.70158 inside Ease.
OutBounce	Bounce easing that simulates a ball dropped onto the end value - the property arrives and then bounces up and down before settling. Produces four distinct bounces of decreasing height. Output stays within [0, 1].
OutCirc	Circular easing based on the equation of a circle that begins steeply and decelerates very gently toward the end. Produces a natural swinging-door deceleration feel.
OutCubic	Cubic easing (power of 3) that begins at full speed and decelerates strongly toward the end. More pronounced deceleration than OutQuad.
OutElastic	Elastic easing that simulates a spring-like overshoot at the end of the animation. The property reaches the end value and then oscillates before settling. Output can exceed [0, 1]. Clamped to exactly 0 at t = 0 and 1 at t = 1.
OutExpo	Exponential easing (base-2 power curve) that begins at explosive speed and decelerates almost to a stop at the end. Formula: f(t) = 1 - 2^(-10*t). Clamped to exactly 1 at t = 1.
OutQuad	Quadratic easing (power of 2) that begins at full speed and decelerates toward the end. Formula: f(t) = t * (2 - t). The default ease type for the Scylla tween system; suitable for most UI transitions.
OutQuart	Quartic easing (power of 4) that begins at full speed and decelerates very strongly toward the end, arriving with a sharp deceleration. Useful for dramatic snap-to animations.
OutQuint	Quintic easing (power of 5) that begins at full speed and decelerates extremely strongly toward the end. The most aggressive of the polynomial ease-out types.
OutSine	Sinusoidal easing that begins at full speed and decelerates toward the end, following the shape of a sine curve: f(t) = sin(t * π/2). Produces the gentlest deceleration of all the power-curve variants.

See Also

Ease

TweenLerp