Tldraw/state/inputs.tsx

import React from 'react'
import { PointerInfo } from 'types'
import vec from 'utils/vec'
import { isDarwin, getPoint } from 'utils/utils'

const DOUBLE_CLICK_DURATION = 300

class Inputs {
  activePointerId?: number
  lastPointerUpTime = 0
  points: Record<string, PointerInfo> = {}
  lastPointer: PointerInfo

  touchStart(e: TouchEvent | React.TouchEvent, target: string) {
    const { shiftKey, ctrlKey, metaKey, altKey } = e

    const touch = e.changedTouches[0]

    const info = {
      target,
      pointerId: touch.identifier,
      origin: getPoint(touch),
      point: getPoint(touch),
      pressure: 0.5,
      shiftKey,
      ctrlKey,
      metaKey: isDarwin() ? metaKey : ctrlKey,
      altKey,
    }

    this.points[touch.identifier] = info
    this.activePointerId = touch.identifier

    this.lastPointer = info
    return info
  }

  touchMove(e: TouchEvent | React.TouchEvent) {
    const { shiftKey, ctrlKey, metaKey, altKey } = e

    const touch = e.changedTouches[0]

    const prev = this.points[touch.identifier]

    const info = {
      ...prev,
      pointerId: touch.identifier,
      point: getPoint(touch),
      pressure: 0.5,
      shiftKey,
      ctrlKey,
      metaKey: isDarwin() ? metaKey : ctrlKey,
      altKey,
    }

    if (this.points[touch.identifier]) {
      this.points[touch.identifier] = info
    }

    this.lastPointer = info
    return info
  }

  pointerDown(e: PointerEvent | React.PointerEvent, target: string) {
    const { shiftKey, ctrlKey, metaKey, altKey } = e

    const info = {
      target,
      pointerId: e.pointerId,
      origin: getPoint(e),
      point: getPoint(e),
      pressure: e.pressure || 0.5,
      shiftKey,
      ctrlKey,
      metaKey: isDarwin() ? metaKey : ctrlKey,
      altKey,
    }

    this.points[e.pointerId] = info
    this.activePointerId = e.pointerId

    this.lastPointer = info
    return info
  }

  pointerEnter(e: PointerEvent | React.PointerEvent, target: string) {
    const { shiftKey, ctrlKey, metaKey, altKey } = e

    const info = {
      target,
      pointerId: e.pointerId,
      origin: getPoint(e),
      point: getPoint(e),
      pressure: e.pressure || 0.5,
      shiftKey,
      ctrlKey,
      metaKey: isDarwin() ? metaKey : ctrlKey,
      altKey,
    }

    this.lastPointer = info
    return info
  }

  pointerMove(e: PointerEvent | React.PointerEvent) {
    const { shiftKey, ctrlKey, metaKey, altKey } = e

    const prev = this.points[e.pointerId]

    const info = {
      ...prev,
      pointerId: e.pointerId,
      point: getPoint(e),
      pressure: e.pressure || 0.5,
      shiftKey,
      ctrlKey,
      metaKey: isDarwin() ? metaKey : ctrlKey,
      altKey,
    }

    if (this.points[e.pointerId]) {
      this.points[e.pointerId] = info
    }

    this.lastPointer = info
    return info
  }

  pointerUp = (e: PointerEvent | React.PointerEvent) => {
    const { shiftKey, ctrlKey, metaKey, altKey } = e

    const prev = this.points[e.pointerId]

    const info = {
      ...prev,
      origin: prev?.origin || getPoint(e),
      point: getPoint(e),
      pressure: e.pressure || 0.5,
      shiftKey,
      ctrlKey,
      metaKey: isDarwin() ? metaKey : ctrlKey,
      altKey,
    }

    delete this.points[e.pointerId]
    delete this.activePointerId

    if (vec.dist(info.origin, info.point) < 8) {
      this.lastPointerUpTime = Date.now()
    }

    this.lastPointer = info
    return info
  }

  wheel = (e: WheelEvent) => {
    const { shiftKey, ctrlKey, metaKey, altKey } = e
    return { point: getPoint(e), shiftKey, ctrlKey, metaKey, altKey }
  }

  canAccept = (pointerId: PointerEvent['pointerId']) => {
    return (
      this.activePointerId === undefined || this.activePointerId === pointerId
    )
  }

  isDoubleClick() {
    if (!this.lastPointer) return

    const { origin, point } = this.lastPointer

    return (
      Date.now() - this.lastPointerUpTime < DOUBLE_CLICK_DURATION &&
      vec.dist(origin, point) < 8
    )
  }

  get pointer() {
    return this.points[Object.keys(this.points)[0]]
  }
}

export default new Inputs()