grabber/PointerEventGrabber.js

import { grabberLogger as logger } from '../configuration/LoggerConfig'

/**
 * Grab pointerDown, pointerMove and pointerUp events
 * @typedef {Object} Grabber
 * @property {function} attach Attach events and decide when to call editor pointerDown/Move/Up methods
 * @property {function} detach Detach the grabber
 */

/**
 * Grabber listener
 * @typedef {Object} GrabberListener
 * @property {Array<String>} types Event types to listen
 * @property {function} listener Event listener for these events
 */

/**
 * Grabber context
 * @typedef {Object} GrabberContext
 * @property {Boolean|Object} options Options object that specifies characteristics about the event listener. (@see addEventListener.options for detail)
 * @property {Array<GrabberListener>} listeners Registered listeners
 */

const floatPrecisionArray = [1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000]

function roundFloat (oneFloat, requestedFloatPrecision) {
  if (requestedFloatPrecision || requestedFloatPrecision === 0) {
    let floatPrecision
    if (requestedFloatPrecision > 10) {
      floatPrecision = floatPrecisionArray[10]
    } else {
      floatPrecision = floatPrecisionArray[requestedFloatPrecision]
    }
    return Math.round(oneFloat * floatPrecision) / floatPrecision
  }
  return oneFloat
}

function extractPoint (event, domElement, configuration, offsetTop = 0, offsetLeft = 0) {
  let eventRef = event
  if (eventRef.changedTouches) {
    eventRef = eventRef.changedTouches[0]
  }
  const rect = domElement.getBoundingClientRect()
  return {
    x: roundFloat(eventRef.clientX - rect.left - domElement.clientLeft - offsetLeft, configuration.xyFloatPrecision),
    y: roundFloat(eventRef.clientY - rect.top - domElement.clientTop - offsetTop, configuration.xyFloatPrecision),
    t: roundFloat(Date.now(), configuration.timestampFloatPrecision)
  }
}

const prevent = (e) => e.preventDefault()
/**
 * Listen for the desired events
 * @param {Element} element DOM element to attach events listeners
 * @param {Editor} editor Editor to received down/move/up events
 * @param {Number} [offsetTop=0]
 * @param {Number} [offsetLeft=0]
 * @return {GrabberContext} Grabber context
 * @listens {Event} pointermove: a pointer moves, similar to touchmove or mousemove.
 * @listens {Event} pointerdown: a pointer is activated, or a device button held.
 * @listens {Event} pointerup: a pointer is deactivated, or a device button released.
 * @listens {Event} pointerover: a pointer has moved onto an element.
 * @listens {Event} pointerout: a pointer is no longer on an element it once was.
 * @listens {Event} pointerenter: a pointer enters the bounding box of an element.
 * @listens {Event} pointerleave: a pointer leaves the bounding box of an element.
 * @listens {Event} pointercancel: a pointer will no longer generate events.
 */
export function attach (element, editor, offsetTop = 0, offsetLeft = 0) {
  let mMaxDiffX = 0

  function unfocus () {
    if (window.getSelection().type !== 'None') {
      window.getSelection().removeAllRanges()
    }
  }

  function hideMenu (evt) {
    const moreMenuInDocument = document.querySelector('.more-menu')
    if (!evt.target.classList.contains('ellipsis') && !evt.target.classList.contains('more-menu') && !evt.target.classList.contains('options-label-button') && moreMenuInDocument && moreMenuInDocument.style.display !== 'none') {
      moreMenuInDocument.style.display = 'none'
      return true
    }
    return false
  }

  function hideCandidates (evt) {
    const candidatesInDocument = document.querySelector('.candidates')
    if (!evt.target.classList.contains('candidates') && !(evt.target.tagName === 'SPAN') && candidatesInDocument && candidatesInDocument.style.display !== 'none') {
      candidatesInDocument.style.display = 'none'
      return true
    }
    return false
  }

  function pointerDownHandler (evt) { // Trigger a pointerDown
    const pointerDownOnEditor = evt.target.id === editor.domElement.id || evt.target.classList.contains('ms-canvas')
    if (this.activePointerId !== undefined) {
      if (this.activePointerId === evt.pointerId) {
        logger.trace(`${evt.type} event with the same id without any pointer up`, evt.pointerId)
      }
    } else if ((evt.button !== 2) && (evt.buttons !== 2) && pointerDownOnEditor) { // Ignore right click
      if (!hideMenu(evt) && !hideCandidates(evt)) {
        this.activePointerId = evt.pointerId
        // Hack for iOS 9 Safari : pointerId has to be int so -1 if > max value
        const pointerId = evt.pointerId > 2147483647 ? -1 : evt.pointerId
        unfocus()
        evt.stopPropagation()
        editor.pointerDown(extractPoint(evt, element, editor.configuration, offsetTop, offsetLeft), evt.pointerType, pointerId)
      }
    } else if (evt.target.classList.contains('ellipsis') || evt.target.classList.contains('tag-icon')) {
      hideMenu(evt)
      hideCandidates(evt)
    } else { // FIXME add more complete verification to pointer down on smartguide
      hideMenu(evt)
      hideCandidates(evt)
      this.smartGuidePointerDown = true
      this.downSmartGuidePoint = extractPoint(evt, element, editor.configuration)
    }
  }

  function pointerMoveHandler (evt) { // Trigger a pointerMove
    // Only considering the active pointer
    if (this.activePointerId !== undefined && this.activePointerId === evt.pointerId) {
      unfocus()
      editor.pointerMove(extractPoint(evt, element, editor.configuration, offsetTop, offsetLeft))
    } else if (this.smartGuidePointerDown) {
      const point = extractPoint(evt, element, editor.configuration, offsetTop, offsetLeft)
      const diffX = Math.abs(this.downSmartGuidePoint.x - point.x)
      const diffY = Math.abs(this.downSmartGuidePoint.y - point.y)
      mMaxDiffX = Math.max(diffX, mMaxDiffX)
      const cond1 = diffX < 5 && diffY > 5 && mMaxDiffX < 15
      const cond2 = diffX > 5 && diffY > 5 && mMaxDiffX < 15
      if (cond1 || cond2) {
        this.activePointerId = evt.pointerId
        // Hack for iOS 9 Safari : pointerId has to be int so -1 if > max value
        const pointerId = evt.pointerId > 2147483647 ? -1 : evt.pointerId
        unfocus()
        editor.pointerDown(this.downSmartGuidePoint, evt.pointerType, pointerId)
      }
    } else {
      logger.trace(`${evt.type} event from another pointerid (${evt.pointerId})`, this.activePointerId)
    }
  }

  function pointerUpHandler (evt) { // Trigger a pointerUp
    mMaxDiffX = 0
    this.smartGuidePointerDown = false
    const smartGuideIds = ['smartguide', 'prompter-text-container', 'prompter-text', 'tag-icon', 'ellipsis']
    const scrollbarClasses = ['ps__rail-x', 'ps__thumb-x']
    // Check if pointer entered into any smartguide elements or scrollbar
    // Use case : when the pointer is entering the smartguide or scrollbar, a pointerout (or leave) is fired.
    // The related target is then the DOM element that was left.
    // We don't want this to cause editor.pointerUp because the stroke isn't finished.
    const pointerEnteredSmartGuide = evt.relatedTarget && (smartGuideIds.includes(evt.relatedTarget.className) || scrollbarClasses.includes(evt.relatedTarget.className))
    // Check if pointer didn't stay in the smartguide and pointer exited the smartguide or scrollbar
    // Use case : when the pointer is leaving the smartguide or scrollbar, a pointerout (or leave) is fired.
    // The related target is then the DOM element that was left (the smart guide)
    // We are entering again the editor
    // We don't want this to cause editor.pointerUp because the stroke isn't finished.
    const pointerExitedSmartGuide = evt.relatedTarget && evt.target && (smartGuideIds.includes(evt.target.className) || scrollbarClasses.includes(evt.target.className))
    // Check if pointer moved between words in smartguide
    // Same use case as pointerEnteredSmartGuide but for the words in the smartguide (each word is a span).
    const pointerMovedWords = evt.relatedTarget && evt.target && (evt.target.tagName === 'SPAN' || evt.relatedTarget.tagName === 'SPAN')
    if (pointerEnteredSmartGuide || pointerExitedSmartGuide || pointerMovedWords) {
      evt.stopPropagation()
    } else if (this.activePointerId !== undefined && this.activePointerId === evt.pointerId) { // Only considering the active pointer
      this.activePointerId = undefined // Managing the active pointer
      evt.stopPropagation()
      editor.pointerUp(extractPoint(evt, element, editor.configuration, offsetTop, offsetLeft))
    } else {
      logger.trace(`${evt.type} event from another pointerid (${evt.pointerId})`, this.activePointerId)
    }
  }

  const context = {
    options: editor.configuration.listenerOptions,
    listeners: [{
      types: ['pointerdown'],
      listener: pointerDownHandler
    }, {
      types: ['pointermove'],
      listener: pointerMoveHandler
    }, {
      types: ['pointerup', 'pointerout', 'pointerleave', 'pointercancel'],
      listener: pointerUpHandler
    }]
  }

  logger.debug('attaching listeners', context)
  context.listeners.forEach((item) => {
    item.types.forEach(type => element.addEventListener(type, item.listener, context.options))
  })

  element.addEventListener('touchmove', prevent)

  // FIXME investigate why this is needed for iOS devices
  document.documentElement.addEventListener('pointerdown', () => {})
  return context
}

export function detach (element, context) {
  logger.debug('detaching listeners', context)
  context.listeners.forEach((item) => {
    item.types.forEach(type => element.removeEventListener(type, item.listener, context.options))
  })
  element.removeEventListener('touchmove', prevent)
  document.documentElement.removeEventListener('pointerdown', () => {})
}