somewhat functioning gesture service

This commit is contained in:
shpuld 2019-03-25 22:44:58 +02:00
parent b13a751926
commit e23c19468a
2 changed files with 81 additions and 11 deletions

View File

@ -1,17 +1,18 @@
import UserCard from '../user_card/user_card.vue'
import { unseenNotificationsFromStore } from '../../services/notification_utils/notification_utils'
// TODO: separate touch gesture stuff into their own utils if more components want them
const deltaCoord = (oldCoord, newCoord) => [newCoord[0] - oldCoord[0], newCoord[1] - oldCoord[1]]
const touchEventCoord = e => ([e.touches[0].screenX, e.touches[0].screenY])
import GestureService from '../../services/gesture_service/gesture_service'
const SideDrawer = {
props: [ 'logout' ],
data: () => ({
closed: true,
touchCoord: [0, 0]
closeGesture: undefined
}),
created () {
const cb = () => this.toggleDrawer()
this.closeGesture = GestureService.swipeGesture(GestureService.DIRECTION_LEFT, cb)
console.log(this.closeGesture)
},
components: { UserCard },
computed: {
currentUser () {
@ -46,13 +47,11 @@ const SideDrawer = {
this.toggleDrawer()
},
touchStart (e) {
this.touchCoord = touchEventCoord(e)
console.log(this)
GestureService.beginSwipe(e, this.closeGesture)
},
touchMove (e) {
const delta = deltaCoord(this.touchCoord, touchEventCoord(e))
if (delta[0] < -30 && Math.abs(delta[1]) < Math.abs(delta[0]) && !this.closed) {
this.toggleDrawer()
}
GestureService.updateSwipe(e, this.closeGesture)
}
}
}

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@ -0,0 +1,71 @@
const DIRECTION_LEFT = [-1, 0]
const DIRECTION_RIGHT = [1, 0]
const DIRECTION_UP = [0, -1]
const DIRECTION_DOWN = [0, 1]
const deltaCoord = (oldCoord, newCoord) => [newCoord[0] - oldCoord[0], newCoord[1] - oldCoord[1]]
const touchEventCoord = e => ([e.touches[0].screenX, e.touches[0].screenY])
const vectorLength = v => Math.sqrt(v[0] * v[0] + v[1] * v[1])
const perpendicular = v => [v[1], v[0]]
const dotProduct = (v1, v2) => v1[0] * v2[0] + v1[1] * v2[1]
const vectorFlatten = (v1, v2) => [v1[0] * v2[0], v1[1] * v2[1]]
// direction: either use the constants above or an arbitrary 2d vector.
// threshold: how many Px to move from touch origin before checking if the
// callback should be called.
// divergentTolerance: a scalr for much of divergent direction we tolerate when
// above threshold. for example, with 1.0 we only call the callback if
// divergent component of delta is < 1.0 * direction component of delta.
const swipeGesture = (direction, onSwipe, threshold = 30, perpendicularTolerance = 1.0) => {
return {
direction,
onSwipe,
threshold,
perpendicularTolerance,
_startPos: [0, 0],
_swiping: false
}
}
const beginSwipe = (event, gesture) => {
gesture._startPos = touchEventCoord(event)
gesture._swiping = true
}
const updateSwipe = (event, gesture) => {
if (!gesture._swiping) return
// movement too small
const delta = deltaCoord(gesture._startPos, touchEventCoord(event))
if (vectorLength(delta) < gesture.threshold) return
// movement is opposite from direction
if (dotProduct(delta, gesture.direction) < 0) return
// movement perpendicular to direction is too much
const towardsDir = vectorFlatten(gesture.direction, delta)
const perpendicularDir = perpendicular(gesture.direction)
const towardsPerpendicular = vectorFlatten(perpendicularDir, delta)
if (
vectorLength(towardsDir) <
gesture.perpendicularTolerance * vectorLength(towardsPerpendicular)
) return
gesture.onSwipe()
gesture._swiping = false
}
const GestureService = {
DIRECTION_LEFT,
DIRECTION_RIGHT,
DIRECTION_UP,
DIRECTION_DOWN,
swipeGesture,
beginSwipe,
updateSwipe
}
export default GestureService