Easing
The Easing
module implements common easing functions. This module is used by Animated.timing() to convey physically believable motion in animations.
You can find a visualization of some common easing functions at http://easings.net/
Predefined animations
The Easing
module provides several predefined animations through the following methods:
back
provides a simple animation where the object goes slightly back before moving forwardbounce
provides a bouncing animationease
provides a simple inertial animationelastic
provides a simple spring interaction
Standard functions
Three standard easing functions are provided:
The poly
function can be used to implement quartic, quintic, and other higher power functions.
Additional functions
Additional mathematical functions are provided by the following methods:
bezier
provides a cubic bezier curvecircle
provides a circular functionsin
provides a sinusoidal functionexp
provides an exponential function
The following helpers are used to modify other easing functions.
in
runs an easing function forwardsinOut
makes any easing function symmetricalout
runs an easing function backwards
Methods
Reference
Methods
step0()
static step0(n)
A stepping function, returns 1 for any positive value of n
.
step1()
static step1(n)
A stepping function, returns 1 if n
is greater than or equal to 1.
linear()
static linear(t)
A linear function, f(t) = t
. Position correlates to elapsed time one to one.
http://cubic-bezier.com/#0,0,1,1
ease()
static ease(t)
A simple inertial interaction, similar to an object slowly accelerating to speed.
http://cubic-bezier.com/#.42,0,1,1
quad()
static quad(t)
A quadratic function, f(t) = t * t
. Position equals the square of elapsed time.
http://easings.net/#easeInQuad
cubic()
static cubic(t)
A cubic function, f(t) = t * t * t
. Position equals the cube of elapsed time.
http://easings.net/#easeInCubic
poly()
static poly(n)
A power function. Position is equal to the Nth power of elapsed time.
n = 4: http://easings.net/#easeInQuart n = 5: http://easings.net/#easeInQuint
sin()
static sin(t)
A sinusoidal function.
http://easings.net/#easeInSine
circle()
static circle(t)
A circular function.
http://easings.net/#easeInCirc
exp()
static exp(t)
An exponential function.
http://easings.net/#easeInExpo
elastic()
static elastic(bounciness)
A simple elastic interaction, similar to a spring oscillating back and forth.
Default bounciness is 1, which overshoots a little bit once. 0 bounciness doesn't overshoot at all, and bounciness of N > 1 will overshoot about N times.
http://easings.net/#easeInElastic
Wolfram Plots:
- http://tiny.cc/elastic_b_1 (bounciness = 1, default)
- http://tiny.cc/elastic_b_3 (bounciness = 3)
back()
static back(s)
Use with Animated.parallel()
to create a simple effect where the object animates back slightly as the animation starts.
Wolfram Plot:
- http://tiny.cc/back_default (s = 1.70158, default)
bounce()
static bounce(t)
Provides a simple bouncing effect.
http://easings.net/#easeInBounce
bezier()
static bezier(x1, y1, x2, y2)
Provides a cubic bezier curve, equivalent to CSS Transitions' transition-timing-function
.
A useful tool to visualize cubic bezier curves can be found at http://cubic-bezier.com/
in()
static in easing;
Runs an easing function forwards.
out()
static out(easing)
Runs an easing function backwards.
inOut()
static inOut(easing)
Makes any easing function symmetrical. The easing function will run forwards for half of the duration, then backwards for the rest of the duration.