react-native-gesture-handler
Version:
Declarative API exposing native platform touch and gesture system to React Native
44 lines (43 loc) • 1.57 kB
JavaScript
import { DiagonalDirections, Directions } from '../../Directions';
import { MINIMAL_RECOGNIZABLE_MAGNITUDE } from '../constants';
export default class Vector {
x;
y;
unitX;
unitY;
_magnitude;
constructor(x, y) {
this.x = x;
this.y = y;
this._magnitude = Math.hypot(this.x, this.y);
const isMagnitudeSufficient = this._magnitude > MINIMAL_RECOGNIZABLE_MAGNITUDE;
this.unitX = isMagnitudeSufficient ? this.x / this._magnitude : 0;
this.unitY = isMagnitudeSufficient ? this.y / this._magnitude : 0;
}
static fromDirection(direction) {
return DirectionToVectorMappings.get(direction) ?? new Vector(0, 0);
}
static fromVelocity(tracker, pointerId) {
const velocity = tracker.getVelocity(pointerId);
return velocity ? new Vector(velocity.x, velocity.y) : null;
}
get magnitude() {
return this._magnitude;
}
computeSimilarity(vector) {
return this.unitX * vector.unitX + this.unitY * vector.unitY;
}
isSimilar(vector, threshold) {
return this.computeSimilarity(vector) > threshold;
}
}
const DirectionToVectorMappings = new Map([
[Directions.LEFT, new Vector(-1, 0)],
[Directions.RIGHT, new Vector(1, 0)],
[Directions.UP, new Vector(0, -1)],
[Directions.DOWN, new Vector(0, 1)],
[DiagonalDirections.UP_RIGHT, new Vector(1, -1)],
[DiagonalDirections.DOWN_RIGHT, new Vector(1, 1)],
[DiagonalDirections.UP_LEFT, new Vector(-1, -1)],
[DiagonalDirections.DOWN_LEFT, new Vector(-1, 1)],
]);