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Add tests for gesture service, fix bug with perpendicular directions

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This commit is contained in:
shpuld 2019-03-26 22:11:45 +02:00
parent e23c19468a
commit c50e64f8ee
2 changed files with 129 additions and 6 deletions
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15
src/services/gesture_service/gesture_service.js
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@ -10,11 +10,14 @@ 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 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]]
const project = (v1, v2) => {
const scalar = (dotProduct(v1, v2) / dotProduct(v2, v2))
return [scalar * v2[0], scalar * 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
@ -46,12 +49,12 @@ const updateSwipe = (event, gesture) => {
// 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 towardsDir = project(delta, gesture.direction)
const perpendicularDir = perpendicular(gesture.direction)
const towardsPerpendicular = vectorFlatten(perpendicularDir, delta)
const towardsPerpendicular = project(delta, perpendicularDir)
if (
vectorLength(towardsDir) <
gesture.perpendicularTolerance * vectorLength(towardsPerpendicular)
vectorLength(towardsDir) * gesture.perpendicularTolerance <
vectorLength(towardsPerpendicular)
) return
gesture.onSwipe()