tldraw/packages/intersect
Steve Ruiz 9b7414509f v1.2.9
2021-12-22 00:46:58 +00:00
..
scripts [improvement] Multiplayer + cursors (#457) 2021-12-22 00:14:38 +00:00
src add triangle tool (#433) 2021-12-09 22:29:09 +00:00
card-repo.png [feature] Add grids (#344) 2021-11-26 15:14:10 +00:00
CHANGELOG.md [feature] Add grids (#344) 2021-11-26 15:14:10 +00:00
LICENSE.md [feature] Add grids (#344) 2021-11-26 15:14:10 +00:00
package.json v1.2.9 2021-12-22 00:46:58 +00:00
README.md [feature] Add grids (#344) 2021-11-26 15:14:10 +00:00
tsconfig.build.json [feature] Add grids (#344) 2021-11-26 15:14:10 +00:00
tsconfig.json [feature] Add grids (#344) 2021-11-26 15:14:10 +00:00

@tldraw/core

This package contains the Renderer and core utilities used by tldraw.

You can use this package to build projects like tldraw, where React components are rendered on a canvas user interface. Check out the advanced example.

💕 Love this library? Consider becoming a sponsor.

Installation

Use your package manager of choice to install @tldraw/core and its peer dependencies.

yarn add @tldraw/core
# or
npm i @tldraw/core

Examples

There are two examples in this repository.

The simple example in the example folder shows a minimal use of the library. It does not do much but this should be a good reference for the API without too much else built on top.

The advanced example in the example-advanced folder shows a more realistic use of the library. (Try it here). While the fundamental patterns are the same, this example contains features such as: panning, pinching, and zooming the camera; creating, cloning, resizing, and deleting shapes; keyboard shortcuts, brush-selection; shape-snapping; undo, redo; and more. Much of the code in the advanced example comes from the @tldraw/tldraw codebase.

If you're working on an app that uses this library, I recommend referring back to the advanced example for tips on how you might implement these features for your own project.

Usage

Import the Renderer React component and pass it the required props.

import * as React from "react"
import { Renderer, TLShape, TLShapeUtil, Vec } from '@tldraw/core'
import { BoxShape, BoxUtil } from "./shapes/box"

const shapeUtils = { box: new BoxUtil() }

function App() {
  const [page, setPage] = React.useState({
    id: "page"
    shapes: {
      "box1": {
        id: 'box1',
        type: 'box',
        parentId: 'page',
        childIndex: 0,
        point: [0, 0],
        size: [100, 100],
        rotation: 0,
      }
    },
    bindings: {}
  })

  const [pageState, setPageState] = React.useState({
    id: "page",
    selectedIds: [],
    camera: {
      point: [0,0],
      zoom: 1
    }
  })

  return (<Renderer
    page={page}
    pageState={pageState}
    shapeUtils={shapeUtils}
  />)
}

Documentation

Renderer

To avoid unnecessary renders, be sure to pass "stable" values as props to the Renderer. Either define these values outside of the parent component, or place them in React state, or memoize them with React.useMemo.

Prop Type Description
page TLPage The current page object.
pageState TLPageState The current page's state.
shapeUtils TLShapeUtils The shape utilities used to render the shapes.

In addition to these required props, the Renderer accents many other optional props.

Property Type Description
containerRef React.MutableRefObject A React ref for the container, where CSS variables will be added.
theme object An object with overrides for the Renderer's default colors.
hideBounds boolean Do not show the bounding box for selected shapes.
hideHandles boolean Do not show handles for shapes with handles.
hideBindingHandles boolean Do not show binding controls for selected shapes with bindings.
hideResizeHandles boolean Do not show resize handles for selected shapes.
hideRotateHandles boolean Do not show rotate handles for selected shapes.
snapLines TLSnapLine[] An array of "snap" lines.
users object A table of TLUsers.
userId object The current user's TLUser id.

The theme object accepts valid CSS colors for the following properties:

Property Description
foreground The primary (usually "text") color
background The default page's background color
brushFill The fill color of the brush selection box
brushStroke The stroke color of the brush selection box
selectFill The fill color of the selection bounds
selectStroke The stroke color of the selection bounds and handles

The Renderer also accepts many (optional) event callbacks.

Prop Description
onPan Panned with the mouse wheel
onZoom Zoomed with the mouse wheel
onPinchStart Began a two-pointer pinch
onPinch Moved their pointers during a pinch
onPinchEnd Stopped a two-pointer pinch
onPointerDown Started pointing
onPointerMove Moved their pointer
onPointerUp Ended a point
onPointCanvas Pointed the canvas
onDoubleClickCanvas Double-pointed the canvas
onRightPointCanvas Right-pointed the canvas
onDragCanvas Dragged the canvas
onReleaseCanvas Stopped pointing the canvas
onHoverShape Moved their pointer onto a shape
onUnhoverShape Moved their pointer off of a shape
onPointShape Pointed a shape
onDoubleClickShape Double-pointed a shape
onRightPointShape Right-pointed a shape
onDragShape Dragged a shape
onReleaseShape Stopped pointing a shape
onHoverHandle Moved their pointer onto a shape handle
onUnhoverHandle Moved their pointer off of a shape handle
onPointHandle Pointed a shape handle
onDoubleClickHandle Double-pointed a shape handle
onRightPointHandle Right-pointed a shape handle
onDragHandle Dragged a shape handle
onReleaseHandle Stopped pointing shape handle
onHoverBounds Moved their pointer onto the selection bounds
onUnhoverBounds Moved their pointer off of the selection bounds
onPointBounds Pointed the selection bounds
onDoubleClickBounds Double-pointed the selection bounds
onRightPointBounds Right-pointed the selection bounds
onDragBounds Dragged the selection bounds
onReleaseBounds Stopped the selection bounds
onHoverBoundsHandle Moved their pointer onto a selection bounds handle
onUnhoverBoundsHandle Moved their pointer off of a selection bounds handle
onPointBoundsHandle Pointed a selection bounds handle
onDoubleClickBoundsHandle Double-pointed a selection bounds handle
onRightPointBoundsHandle Right-pointed a selection bounds handle
onDragBoundsHandle Dragged a selection bounds handle
onReleaseBoundsHandle Stopped a selection bounds handle
onShapeClone Clicked on a shape's clone handle
onShapeChange A shape's component prompted a change
onShapeBlur A shape's component was prompted a blur
onRenderCountChange The number of rendered shapes changed
onBoundsChange The Renderer's screen bounding box of the component changed
onError The Renderer encountered an error

The @tldraw/core library provides types for most of the event handlers:

Type
TLPinchEventHandler
TLPointerEventHandler
TLCanvasEventHandler
TLBoundsEventHandler
TLBoundsHandleEventHandler
TLShapeChangeHandler
TLShapeBlurHandler
TLShapeCloneHandler

TLPage

An object describing the current page. It contains:

Property Type Description
id string A unique id for the page.
shapes TLShape{} A table of shapes.
bindings TLBinding{} A table of bindings.
backgroundColor string (optional) The page's background fill color. Will also overwrite the theme.

TLPageState

An object describing the current page. It contains:

Property Type Description
id string The corresponding page's id
selectedIds string[] An array of selected shape ids
camera object An object describing the camera state
camera.point number[] The camera's [x, y] coordinates
camera.zoom number The camera's zoom level
pointedId string (optional) The currently pointed shape id
hoveredId string (optional) The currently hovered shape id
editingId string (optional) The currently editing shape id
bindingId string (optional) The currently editing binding.
brush TLBounds (optional) A Bounds for the current selection box

TLShape

An object that describes a shape on the page. The shapes in your document should extend this interface with other properties. See Shape Type.

Property Type Description
id string The shape's id.
type string The type of the shape, corresponding to the type of a TLShapeUtil
parentId string The id of the shape's parent (either the current page or another shape)
childIndex number the order of the shape among its parent's children
name string the name of the shape
point number[] the shape's current [x, y] coordinates on the page
rotation number (optiona) The shape's current rotation in radians
children string[] (optional) An array containing the ids of this shape's children
handles {} (optional) A table of TLHandle objects
isGhost boolean (optional) True if the shape is "ghosted", e.g. while deleting
isLocked boolean (optional) True if the shape is locked
isHidden boolean (optional) True if the shape is hidden
isEditing boolean (optional) True if the shape is currently editing
isGenerated boolean optional) True if the shape is generated programatically
isAspectRatioLocked boolean (optional) True if the shape's aspect ratio is locked

TLHandle

An object that describes a relationship between two shapes on the page.

Property Type Description
id string An id for the handle
index number The handle's order within the shape's handles
point number[] The handle's [x, y] coordinates

When a shape with handles is the only selected shape, the Renderer will display its handles. You can respond to interactions with these handles using the `on

TLBinding

An object that describes a relationship between two shapes on the page.

Property Type Description
id string A unique id for the binding
fromId string The id of the shape where the binding begins
toId string The id of the shape where the binding begins

TLSnapLine

A snapline is an array of points (formatted as [x, y]) that represent a "snapping" line.

TLShapeUtil

The TLShapeUtil is an abstract class that you can extend to create utilities for your custom shapes. See the Creating Shapes guide to learn more.

TLUser

A TLUser is the presence information for a multiplayer user. The user's pointer location and selections will be shown on the canvas. If the TLUser's id matches the Renderer's userId prop, then the user's cursor and selections will not be shown.

Property Type Description
id string A unique id for the user
color string The user's color, used for indicators
point number[] The user's pointer location on the page
selectedIds[] string[] The user's selected shape ids

Utils

A general purpose utility class. See source for more.

Guide: Creating Shapes

The Renderer component has no built-in shapes. It's up to you to define every shape that you want to see on the canvas. While these shapes are highly reusable between projects, you'll need to define them using the API described below.

For several example shapes, see the folder /example/src/shapes/.

Shape Type

Your first task is to define an interface for the shape that extends TLShape. It must have a type property.

// BoxShape.ts
import type { TLShape } from '@tldraw/core'

export interface BoxShape extends TLShape {
  type: 'box'
  size: number[]
}

Component

Next, use TLShapeUtil.Component to create a second component for your shape's Component. The Renderer will use this component to display the shape on the canvas.

// BoxComponent.ts

import * as React from 'react'
import { shapeComponent, SVGContainer } from '@tldraw/core'
import type { BoxShape } from './BoxShape'

export const BoxComponent = TLShapeUtil.Component<BoxShape, SVGSVGElement>(
  ({ shape, events, meta }, ref) => {
    const color = meta.isDarkMode ? 'white' : 'black'

    return (
      <SVGContainer ref={ref} {...events}>
        <rect
          width={shape.size[0]}
          height={shape.size[1]}
          stroke={color}
          strokeWidth={2}
          strokeLinejoin="round"
          fill="none"
          pointerEvents="all"
        />
      </SVGContainer>
    )
  }
)

Your component can return HTML elements or SVG elements. If your shape is returning only SVG elements, wrap it in an SVGContainer. If your shape returns HTML elements, wrap it in an HTMLContainer. Not that you must set pointerEvents manually on the shapes you wish to receive pointer events.

The component will receive the following props:

Name Type Description
shape TLShape The shape from page.shapes that is being rendered
meta {} The value provided to the Renderer's meta prop
events {} Several pointer events that should be set on the container element
isSelected boolean The shape is selected (its id is in pageState.selectedIds)
isHovered boolean The shape is hovered (its id is pageState.hoveredId)
isEditing boolean The shape is being edited (its id is pageState.editingId)
isGhost boolean The shape is ghosted or is the child of a ghosted shape.
isChildOfSelected boolean The shape is the child of a selected shape.
onShapeChange Function The callback provided to the Renderer's onShapeChange prop
onShapeBlur Function The callback provided to the Renderer's onShapeBlur prop

Indicator

Next, use TLShapeUtil.Indicator to create a second component for your shape's Indicator. This component is shown when the shape is hovered or selected. Your Indicator must return SVG elements only.

// BoxIndicator.ts

export const BoxIndicator = TLShapeUtil.Indicator<BoxShape>(({ shape }) => {
  return (
    <rect
      fill="none"
      stroke="dodgerblue"
      strokeWidth={1}
      width={shape.size[0]}
      height={shape.size[1]}
    />
  )
})

The indicator component will receive the following props:

Name Type Description
shape TLShape The shape from page.shapes that is being rendered
meta {} The value provided to the Renderer's meta prop
user TLUser The user when shown in a multiplayer session
isSelected boolean Whether the current shape is selected (true if its id is in pageState.selectedIds)
isHovered boolean Whether the current shape is hovered (true if its id is pageState.hoveredId)

ShapeUtil

Next, create a "shape util" for your shape. This is a class that extends TLShapeUtil. The Renderer will use an instance of this class to answer questions about the shape: what it should look like, where it is on screen, whether it can rotate, etc.

// BoxUtil.ts

import { Utils, TLBounds, TLShapeUtil } from '@tldraw/core'
import { BoxComponent } from './BoxComponent'
import { BoxIndicator } from './BoxIndicator'
import type { BoxShape } from './BoxShape'

export class BoxUtil extends TLShapeUtil<BoxShape, SVGSVGElement> {
  Component = BoxComponent

  Indicator = BoxIndicator

  getBounds = (shape: BoxShape): TLBounds => {
    const [width, height] = shape.size

    const bounds = {
      minX: 0,
      maxX: width,
      minY: 0,
      maxY: height,
      width,
      height,
    }

    return Utils.translateBounds(bounds, shape.point)
  }
}

Set the Component field to your component and the Indicator field to your indicator component. Then define the getBounds method. This method will receive a shape and should return a TLBounds object.

You may also set the following fields:

Name Type Default Description
showCloneHandles boolean false Whether to display clone handles when the shape is the only selected shape
hideBounds boolean false Whether to hide the bounds when the shape is the only selected shape
isStateful boolean false Whether the shape has its own React state. When true, the shape will not be unmounted when off-screen

ShapeUtils Object

Finally, create a mapping of your project's shape utils and the type properties of their corresponding shapes. Pass this object to the Renderer's shapeUtils prop.

// App.tsx

const shapeUtils = {
  box: new BoxUtil(),
  circle: new CircleUtil(),
  text: new TextUtil(),
}

export function App() {
  // ...

  return <Renderer page={page} pageState={pageState} {...etc} shapeUtils={shapeUtils} />
}

Local Development

To start the development servers for the package and the advanced example:

  • Run yarn to install dependencies.
  • Run yarn start.
  • Open localhost:5420.

You can also run:

  • start:advanced to start development servers for the package and the advanced example.
  • start:simple to start development servers for the package and the simple example.
  • test to execute unit tests via Jest.
  • docs to build the docs via ts-doc.
  • build to build the package.

Example

See the example folder or this CodeSandbox example.

Community

Support

Need help? Please open an issue for support.

Discussion

Want to connect with other devs? Visit the Discord channel.

License

This project is licensed under MIT.

If you're using the library in a commercial product, please consider becoming a sponsor.

Author