redash

Utility library for React Native Gesture Handler and Reanimated.

Usage

yarn add react-native-redash

import { atan2 } from "react-native-redash";

atan2(y, x);

Components

<ReText>

Component that display an animation value as text.

Example usage:

<ReText text={new Value("hello world!")} style={{ color: "blue" }} />

SVG

parsePath(SVGPath: String): ReanimatedPath

Given an SVG Path, returns an denormalized object of values that can be used for animations on that path. From the perspective of the user, the returned value should be considered a black box. Here is an example below:

// We get the data from the SVG Path denormalized a way that can be handled with Reanimated
const path = parsePath(d);
const { y, x } = getPointAtLength(path, length);

getPointAtLength(path): { x: Node, y: Node }

Implementation of getPointAtLength for Reanimated.

// We get the data from the SVG Path denormalized a way that can be handled with Reanimated
const path = parsePath(d);
const { y, x } = getPointAtLength(path, length);

interpolatePath(value: Node, { inputRange, outputRange }): path

Interpolate from one SVG point to the other, this function assumes that each path has the same number of points.

  const phone1 = "M 18 149C 18 149 25 149 25 149 25 14...";
  const d = interpolatePath(slider, {
    inputRange: [0, width, width * 2],
    outputRange: [phone1, phone2, phone3]
  });
  return (
      <Svg style={styles.svg} viewBox="0 0 100 300">
        <AnimatedPath fill="black" {...{ d }} />
      </Svg>
  );

bInterpolatePath(progress, path1, path2): path

Interpolate from one SVG point to the other, this function assumes that each path has the same number of points.

const rhino = "M 217.765 29.683 C 225.855 29.683 ";
const elephant = "M 223.174 43.413 ...";
return (
    <>
      <Animated.Code>
        {() =>
          set(
            progress,
            runTiming(clock, progress, {
              toValue: 1,
              duration: 2000,
              easing: Easing.linear
            })
          )
        }
      </Animated.Code>
      <Svg style={styles.container} viewBox="0 0 409 280">
        <AnimatedPath
          d={bInterpolatePath(progress, rhino, elephant)}
          fill="#7d8f9b"
        />
      </Svg>
    </>
  );

Math

toRad(node)

Transforms an angle in degrees in radians.

(deg: Node) => Node;

toDeg(node)

Transforms an angle in radians in degrees.

toDeg(rad: Node) => Node

min(...nodes)

Takes one or more nodes as an input and returns a minimum of all the node's values. This is equivalent to Animated.min but with support for more than two parameters.

min(...args: Node[]) => Node

max(...nodes)

Takes one or more nodes as an input and returns a maximum of all the node's values. This is equivalent to Animated.min but with support for more than two parameters.

max(...args: Node[]) => Node

clamp(node: Node, lowerBound: Adaptable, upperBound: Adaptable)

Clamps a node with a lower and upper bound.

clamp(new Value(-1), 0, 100); // 0
clamp(new Value(1), 0, 100); // 1
clamp(new Value(101), 0, 100); // 100

atan(node)

Returns a arc-tangent of the value in radians of the given node. We provide this function in case you are using a version of reanimated that doesn't ship atan. Beware that this function is not as precise at Math.atan() nor Animated.atan().

atan(rad: Node) => Node

atan2(node)

Returns the angle in the plane (in radians) between the positive x-axis and the ray from (0,0) to the point (x,y), atan2(y,x). Beware that this function is not as precise at Math.atan2().

atan2(y: Node, x Node) => Node

cubicBezier(t, p0, p1, p2, p3)

Returns the coordinate of a cubic bezier curve. t is the length of the curve from 0 to 1. cubicBezier(0, p0, p1, p2, p3) equals p0 and cubicBezier(1, p0, p1, p2, p3) equals p3. p0 and p3 are respectively the starting and ending point of the curve. p1 and p2 are the control points.

String

string

Tagged template for animated string values.

const { x, y } = { x: new Value(0), y: new Value(0) };
const d = string`M0,0 ${x},${y}`;
return <AnimatedPath {...{d}} />;

Array

find(nodes, index, notFound)

Returns the node from the list of nodes at the specified index. If not, it returns the notFound node.

find(values: Node[], index: Node, notFound: Node) => Node

contains(nodes, index, notFound)

Returns 1 if the node value is contained in the array of nodes, 0 otherwise.

contains(values: Node[], value: Node) => Node

Animations

runTiming(clock, value, config)

Convenience function to run a timing animation.

runTiming(clock: Clock, value: Node, config: TimingConfig): Node

Example usage:

const config = {
  duration: 10 * 1000,
  toValue: 1,
  easing: Easing.linear,
};
runTiming(clock, 0, config);

runDecay(clock, value, velocity, rerunDecaying)

Convenience function to run a decay animation.

runDecay(clock: Clock, value: Node, velocity: Node, rerunDecaying: Node): Node

bInterpolate(node, from, to)

Interpolate the node from 0 to 1 without clamping.

interpolateColor(node, { inputRange, outputRange }, [colorSpace = "hsv"])

Interpolate colors based on an animation value and its value range.

interpolateColor(value: Node, { inputRange: number[], outputRange: Colors }, colorSpace?: "hsv" | "rgb")

Example Usage:

const from = {
  r: 197,
  g: 43,
  b: 39,
};
const to = {
  r: 225,
  g: 176,
  b: 68,
};

// Interpolate in default color space (HSV)
interpolateColor(x, [0, 1], [from, to]);

// Interpolate in RGB color space
interpolateColor(x, [0, 1], [from, to], "rgb");

bInterpolateColor(node, color1, color2, [colorSpace = "hsv"])

Interpolate the node from 0 to 1 without clamping.

snapPoint(point, velocity, points)

Select a point based on a node value and its velocity. Example usage:

const snapPoints = [-width, 0, width];
runSpring(clock, x, snapPoint(x, velocityX, snapPoints));

Transformations

translateZ

Convert a translateZ transformation into a scale transformation.

translateZ(perspective: Node, z: Node)

Example usage with transform.

const perspective = 800;
const z = new Value(100);
//...
transform: [{ perspective }, translateZ(perspective, z)];

Gestures

onScroll({ x: node, y: node })

Returns a reanimated event handler for the ScrollView.

onScroll(contentOffset: { x?: Node; y?: Node; }) => EventNode

Example usage for a vertical ScrollView.

<Animated.ScrollView onScroll={onScroll({ y: new Value(0) })} vertical />

And for an horizontal one.

<Animated.ScrollView onScroll={onScroll({ x: new Value(0) })} horizontal />

decay

Decorates animated value to decay after pan

• How it works
• Example usage

constructor(props) {
  const dragX = new Value(0);
  const panState = new Value(0);
  const velocityX = new Value(0);

  this.handlePan = event([
    {
      nativeEvent: {
        translationX: dragX,
        state: panState,
        velocityX,
      },
    },
  ]);

  this.X = decay(dragX, panState, velocityX);
}

preserveOffset

Decorates animated value to save previous offset of pan

• How it works
• Example usage

constructor(props) {
  const dragX = new Value(0);
  const panState = new Value(0);

  this.handlePan = event([
    {
      nativeEvent: {
        translationX: dragX,
        state: panState,
      },
    },
  ]);

  this.X = preserveOffset(dragX, panState);
}

preserveMultiplicativeOffset

Decorates animated value to save previous offset of pinch

• How it works
• Example usage

constructor(props) {
  const scale = new Value(1);
  const scaleState = new Value(0);

  this.handleZoom = event([
    {
      nativeEvent: {
        scale,
        state: panState,
      },
    },
  ]);

  this.X = preserveMultiplicativeOffset(scale, scaleState);
}

limit

Decorates animated value to set limits of panning

• How it works
• Example usage

constructor(props) {
  const dragX = new Value(0);
  const panState = new Value(0);

  this.handlePan = event([
    {
      nativeEvent: {
        translationX: dragX,
        state: panState,
      },
    },
  ]);

  this.X = limit(dragX, panState, -100, 100);
}

spring

Decorates animated value to spring after pan

constructor(props) {
  const dragX = new Value(0);
  const panState = new Value(0);
  const snapPoint = new Value(100);

  this.handlePan = event([
    {
      nativeEvent: {
        state: panState,
        velocityX,
      },
    },
  ]);

  this.X = spring(dragX, panState, snapPoint);
}