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spring()

A physics-based animation primitive.

Example:

spring-example.ts
tsx
const frame = useCurrentFrame();
const { fps } = useVideoConfig();
 
const value = spring({
frame,
fps,
config: {
stiffness: 100,
},
});
spring-example.ts
tsx
const frame = useCurrentFrame();
const { fps } = useVideoConfig();
 
const value = spring({
frame,
fps,
config: {
stiffness: 100,
},
});

Parameters

frame

The current time value. Most of the time you want to pass in the return value of useCurrentFrame(). The spring animation starts at frame 0, so if you would like to delay the animation, you can pass a different value like frame - 20.

from

Default: 0

The initial value of the animation.

to

Default: 1

The end value of the animation. Note that depending on the parameters, spring animations may overshoot the target a bit, before they bounce back to their final target.

fps

For how many frames per second the spring animation should be calculated. This should always be the fps property of the return value of useVideoConfig().

reverse

Default: false

Render the animation in reverse. See: Order of operations

config

An optional object that allows you to customize the physical properties of the animation.

mass

Default: 1

The weight of the spring. If you reduce the mass, the animation becomes faster!

damping

Default: 10

How hard the animation decelerates.

stiffness

Default: 100

Spring stiffness coefficient. Play with this one and it will affect how bouncy your animation is.

overshootClamping

Default: false

Determines whether the animation can shoot over the to value. If set to true, if the animation goes over to, it will just return the value of to.

durationInFrames

optional

Stretches the animation curve so it is exactly as long as you specify.

spring-example.ts
tsx
const frame = useCurrentFrame();
const { fps } = useVideoConfig();
 
const value = spring({
frame,
fps,
config: {
stiffness: 100,
},
durationInFrames: 40,
});
spring-example.ts
tsx
const frame = useCurrentFrame();
const { fps } = useVideoConfig();
 
const value = spring({
frame,
fps,
config: {
stiffness: 100,
},
durationInFrames: 40,
});

See also: Order or operations

durationRestThreshold

optional

How close the animation should be to the end in order to be considered finished for the calculation of the duration. Only has an effect if durationInFrames is also specified.

For example, if a durationRestThreshold of 0.001 is given, and the durationOfFrames is 30, it means that after 30 frames, the spring has reached 99.9% (1 - 0.001 = 0.999) of it's distance to the end value.

delay

optional

How many frames to delay the animation for.

For example, if a delay of 25 is given frames 0-24 will return the initial value, and the animation will effectively start from frame 25. See also: Order or operations

Order of operations

Here is the order of which the durationInFrames, reverse and delay operations are applied:

1 First the spring animation is stretched to the duration that you pass using durationInFrames, if you pass a duration.
2 Then the animation is reversed if you pass reverse: true.
3 Then the animation is delayed if you pass delay.

Credit

This function was taken from Reanimated 2, which in itself was a huge inspiration for Remotion.

See also