tldraw/state/sessions/draw-session.ts
2021-06-29 13:00:59 +01:00

153 lines
4.4 KiB
TypeScript

import { current } from 'immer'
import { Data, DrawShape } from 'types'
import BaseSession from './base-session'
import { getShapeUtils } from 'state/shape-utils'
import { getBoundsFromPoints } from 'utils'
import tld from 'utils/tld'
import vec from 'utils/vec'
import commands from 'state/commands'
export default class DrawSession extends BaseSession {
origin: number[]
previous: number[]
last: number[]
points: number[][]
snapshot: DrawSnapshot
isLocked: boolean
lockedDirection: 'horizontal' | 'vertical'
constructor(data: Data, id: string, point: number[]) {
super(data)
this.origin = point
this.previous = point
this.last = point
this.snapshot = getDrawSnapshot(data, id)
// Add a first point but don't update the shape yet. We'll update
// when the draw session ends; if the user hasn't added additional
// points, this single point will be interpreted as a "dot" shape.
this.points = [[0, 0, 0.5]]
const shape = tld.getPage(data).shapes[id]
getShapeUtils(shape).translateTo(shape, point)
tld.updateParents(data, [shape.id])
}
update = (
data: Data,
point: number[],
pressure: number,
isLocked = false
): void => {
const { snapshot } = this
// Drawing while holding shift will "lock" the pen to either the
// x or y axis, depending on which direction has the greater
// delta. Pressing shift will also add more points to "return"
// the pen to the axis.
if (isLocked) {
if (!this.isLocked && this.points.length > 1) {
const bounds = getBoundsFromPoints(this.points)
if (bounds.width > 8 || bounds.height > 8) {
this.isLocked = true
const returning = [...this.previous]
const isVertical = bounds.height > 8
if (isVertical) {
this.lockedDirection = 'vertical'
returning[0] = this.origin[0]
} else {
this.lockedDirection = 'horizontal'
returning[1] = this.origin[1]
}
this.previous = returning
this.points.push(vec.sub(returning, this.origin))
}
}
} else if (this.isLocked) {
this.isLocked = false
}
if (this.isLocked) {
if (this.lockedDirection === 'vertical') {
point[0] = this.origin[0]
} else {
point[1] = this.origin[1]
}
}
// Low pass the current input point against the previous one
const nextPrev = vec.med(this.previous, point)
this.previous = nextPrev
// Don't add duplicate points. It's important to test against the
// adjusted (low-passed) point rather than the input point.
const newPoint = vec.round([
...vec.sub(this.previous, this.origin),
pressure,
])
if (vec.isEqual(this.last, newPoint)) return
this.last = newPoint
this.points.push(newPoint)
// We draw a dot when the number of points is 1 or 2, so this guard
// prevents a "flash" of a dot when a user begins drawing a line.
if (this.points.length <= 2) return
// Update the points and update the shape's parents.
const shape = tld.getShape(data, snapshot.id) as DrawShape
// Note: Normally we would want to spread the points to create a new
// array, however we create the new array in hacks/fastDrawUpdate.
getShapeUtils(shape).setProperty(shape, 'points', this.points)
tld.updateParents(data, [shape.id])
}
cancel = (data: Data): void => {
const { snapshot } = this
const shape = tld.getShape(data, snapshot.id) as DrawShape
getShapeUtils(shape).translateTo(shape, snapshot.point)
getShapeUtils(shape).setProperty(shape, 'points', snapshot.points)
tld.updateParents(data, [shape.id])
}
complete = (data: Data): void => {
const { snapshot } = this
const page = tld.getPage(data)
const shape = page.shapes[snapshot.id] as DrawShape
if (shape.points.length < this.points.length) {
getShapeUtils(shape).setProperty(shape, 'points', this.points)
}
getShapeUtils(shape).onSessionComplete(shape)
tld.updateParents(data, [shape.id])
commands.draw(data, this.snapshot.id)
}
}
// eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
export function getDrawSnapshot(data: Data, shapeId: string) {
const page = tld.getPage(current(data))
const { points, point } = page.shapes[shapeId] as DrawShape
return {
id: shapeId,
point,
points,
}
}
export type DrawSnapshot = ReturnType<typeof getDrawSnapshot>