Add swipe-click handler to media modal

Now swiping will correctly change the current media, and with a good
preview. Clicking without swiping closes the overlay.

src/services/gesture_service/gesture_service.js

@@ -4,25 +4,27 @@ const DIRECTION_RIGHT = [1, 0]
 const DIRECTION_UP = [0, -1]
 const DIRECTION_DOWN = [0, 1]
 
-const DISTANCE_MIN = 1
+// const DISTANCE_MIN = 1
 
-const isSwipeEvent = e => (e.touches.length === 1)
-const isSwipeEventEnd = e => (e.changedTouches.length === 1)
+// const isSwipeEvent = e => (e.touches.length === 1)
+// const isSwipeEventEnd = e => (e.changedTouches.length === 1)
 
-const isScaleEvent = e => (e.targetTouches.length === 2)
-const isScaleEventEnd = e => (e.targetTouches.length === 1)
+// const isScaleEvent = e => (e.targetTouches.length === 2)
+// const isScaleEventEnd = e => (e.targetTouches.length === 1)
 
 const deltaCoord = (oldCoord, newCoord) => [newCoord[0] - oldCoord[0], newCoord[1] - oldCoord[1]]
 
-const vectorMinus = (a, b) => a.map((k, n) => k - b[n])
-const vectorAdd = (a, b) => a.map((k, n) => k + b[n])
+// const vectorMinus = (a, b) => a.map((k, n) => k - b[n])
+// const vectorAdd = (a, b) => a.map((k, n) => k + b[n])
 
-const avgCoord = (coords) => [...coords].reduce(vectorAdd, [0, 0]).map(d => d / coords.length)
+// const avgCoord = (coords) => [...coords].reduce(vectorAdd, [0, 0]).map(d => d / coords.length)
 
 const touchCoord = touch => [touch.screenX, touch.screenY]
 
 const touchEventCoord = e => touchCoord(e.touches[0])
 
+const pointerEventCoord = e => [e.clientX, e.clientY]
+
 const vectorLength = v => Math.sqrt(v[0] * v[0] + v[1] * v[1])
 
 const perpendicular = v => [v[1], -v[0]]
@@ -78,104 +80,87 @@ const updateSwipe = (event, gesture) => {
   gesture._swiping = false
 }
 
-class SwipeAndScaleGesture {
+class SwipeAndClickGesture {
   // swipePreviewCallback(offsets: Array[Number])
   //   offsets: the offset vector which the underlying component should move, from the starting position
-  // pinchPreviewCallback(offsets: Array[Number], scaling: Number)
-  //   offsets: the offset vector which the underlying component should move, from the starting position
-  //   scaling: the scaling factor we should apply to the underlying component, from the starting position
-  // swipeEndcallback(sign: 0|-1|1)
+  // swipeEndCallback(sign: 0|-1|1)
   //   sign: if the swipe does not meet the threshold, 0
   //         if the swipe meets the threshold in the positive direction, 1
   //         if the swipe meets the threshold in the negative direction, -1
   constructor ({
     direction,
-    // swipeStartCallback, pinchStartCallback,
-    swipePreviewCallback, pinchPreviewCallback,
-    swipeEndCallback, pinchEndCallback,
+    // swipeStartCallback
+    swipePreviewCallback,
+    swipeEndCallback,
+    swipeCancelCallback,
+    swipelessClickCallback,
     threshold = 30, perpendicularTolerance = 1.0
   }) {
     const nop = () => { console.log('Warning: Not implemented') }
     this.direction = direction
     this.swipePreviewCallback = swipePreviewCallback || nop
-    this.pinchPreviewCallback = pinchPreviewCallback || nop
     this.swipeEndCallback = swipeEndCallback || nop
-    this.pinchEndCallback = pinchEndCallback || nop
+    this.swipeCancelCallback = swipeCancelCallback || nop
+    this.swipelessClickCallback = swipelessClickCallback || nop
     this.threshold = threshold
     this.perpendicularTolerance = perpendicularTolerance
+    this._reset()
+  }
+
+  _reset () {
     this._startPos = [0, 0]
-    this._startDistance = DISTANCE_MIN
+    this._pointerId = -1
     this._swiping = false
+    this._swiped = false
   }
 
   start (event) {
     console.log('start() called', event)
-    if (isSwipeEvent(event)) {
-      this._startPos = touchEventCoord(event)
-      console.log('start pos:', this._startPos)
-      this._swiping = true
-    } else if (isScaleEvent(event)) {
-      const coords = [...event.targetTouches].map(touchCoord)
-      this._startPos = avgCoord(coords)
-      this._startDistance = vectorLength(deltaCoord(coords[0], coords[1]))
-      if (this._startDistance < DISTANCE_MIN) {
-        this._startDistance = DISTANCE_MIN
-      }
-      this._scalePoints = [...event.targetTouches]
-      this._swiping = false
-      console.log(
-        'is scale event, start =', this._startPos,
-        'dist =', this._startDistance)
-    }
+
+    this._startPos = pointerEventCoord(event)
+    this._pointerId = event.pointerId
+    console.log('start pos:', this._startPos)
+    this._swiping = true
+    this._swiped = false
   }
 
   move (event) {
-    // console.log('move called', event)
-    if (isSwipeEvent(event)) {
-      const touch = event.changedTouches[0]
-      const delta = deltaCoord(this._startPos, touchCoord(touch))
+    if (this._swiping && this._pointerId === event.pointerId) {
+      this._swiped = true
+
+      const coord = pointerEventCoord(event)
+      const delta = deltaCoord(this._startPos, coord)
 
       this.swipePreviewCallback(delta)
-    } else if (isScaleEvent(event)) {
-      console.log('is scale event')
-      const coords = [...event.targetTouches].map(touchCoord)
-      const curPos = avgCoord(coords)
-      const curDistance = vectorLength(deltaCoord(coords[0], coords[1]))
-      const scaling = curDistance / this._startDistance
-      const posDiff = vectorMinus(curPos, this._startPos)
-      // const delta = vectorAdd(numProduct((1 - scaling), this._startPos), posDiff)
-      const delta = posDiff
-      // console.log(
-      //   'is scale event, cur =', curPos,
-      //   'dist =', curDistance,
-      //   'scale =', scaling,
-      //   'delta =', delta)
-      this.pinchPreviewCallback(delta, scaling)
     }
   }
 
-  end (event) {
-    console.log('end() called', event)
-    if (isScaleEventEnd(event)) {
-      this.pinchEndCallback()
-    }
-
-    if (!isSwipeEventEnd(event)) {
-      console.log('not swipe event')
+  cancel (event) {
+    if (!this._swiping || this._pointerId !== event.pointerId) {
       return
     }
+
+    this.swipeCancelCallback()
+  }
+
+  end (event) {
     if (!this._swiping) {
       console.log('not swiping')
       return
     }
-    this.swiping = false
 
-    console.log('is swipe event')
+    if (this._pointerId !== event.pointerId) {
+      console.log('pointer id does not match')
+      return
+    }
+
+    this._swiping = false
+
+    console.log('end: is swipe event')
 
     // movement too small
-    const touch = event.changedTouches[0]
-    const delta = deltaCoord(this._startPos, touchCoord(touch))
-    this.swipePreviewCallback(delta)
+    const coord = pointerEventCoord(event)
+    const delta = deltaCoord(this._startPos, coord)
 
     const sign = (() => {
       if (vectorLength(delta) < this.threshold) {
@@ -198,7 +183,12 @@ class SwipeAndScaleGesture {
       return isPositive ? 1 : -1
     })()
 
-    this.swipeEndCallback(sign)
+    if (this._swiped) {
+      this.swipeEndCallback(sign)
+    } else {
+      this.swipelessClickCallback()
+    }
+    this._reset()
   }
 }
 
@@ -210,7 +200,7 @@ const GestureService = {
   swipeGesture,
   beginSwipe,
   updateSwipe,
-  SwipeAndScaleGesture
+  SwipeAndClickGesture
 }
 
 export default GestureService