chq2018515 / react-sketch-canvas

React component to draw using SVG

Freehand vector drawing tool for React using SVG as canvas 🖌

Overview

Features

• Supports Desktop and Mobile.
• Accepts input from Mouse, touch, and graphic tablets.

Requirements

• Requires React 16.4
• Depends on Immer and pepjs

Wanna test React Sketch Canvas before using it?

• Try here

Installation

If you use npm

npm i react-sketch-canvas

or with yarn

yarn add react-sketch-canvas

Example

Common usage example

import React from "react";
import { ReactSketchCanvas } from "react-sketch-canvas";

const styles = {
  border: "0.0625rem solid #9c9c9c",
  borderRadius: "0.25rem",
};

const Canvas = () => {
  return (
    <ReactSketchCanvas
      style={styles}
      width="600"
      height="400"
      strokeWidth={4}
      strokeColor="red"
    />
  );
};

To export Data URL of your sketch use ref

import React from "react";
import { ReactSketchCanvas } from "react-sketch-canvas";

const styles = {
  border: "0.0625rem solid #9c9c9c",
  borderRadius: "0.25rem"
};

const Canvas = class extends React.Component {
  constructor(props) {
    super(props);

    this.canvas = React.createRef();
  }

  render() {
    return (
      <div>
        <ReactSketchCanvas
          ref={this.canvas}
          strokeWidth={5}
          strokeColor="black"
        />
        <button
          onClick={() => {
            this.canvas.current.
              .exportImage("png")
              .then(data => {
                console.log(data);
              })
              .catch(e => {
                console.log(e);
              });
          }}
        >
          Get Image
        </button>
      </div>
    );
  }
};

List of Props

Props	Expected datatype	Default value	Description
className	PropTypes.string	""	Class for using with CSS selectors
width	PropTypes.string	100%	canvas width (em/rem/px)
height	PropTypes.string	100%	canvas width (em/rem/px)
canvasColor	PropTypes.string	white	canvas color (HTML colors)
background	PropTypes.string	''	Set SVG background using CSS background value
strokeColor	PropTypes.string	black	Pen color
strokeWidth	PropTypes.number	4	Pen stroke size
eraserWidth	PropTypes.number	8	Erase size
allowOnlyPointerType	PropTypes.string	all	allow pointer type ("all"/"mouse"/"pen"/"touch")
onUpdate	PropTypes.func	all	Returns the current sketch path in CanvasPath type on every update
withTimestamp	PropTypes.bool	false	Add timestamp to individual strokes for measuring sketching time

Set SVG background using CSS background value

You can specify width and height values in em or rem. It fills the parent element space if width and height are not set

Example

<ReactSketchCanvas width="25em" height="10rem" />

Styling

You can pass a CSS in JS style object to style the element. By default it has a border with following properties

canvas {
  border: 0.0625rem solid #9c9c9c;
  border-radius: 0.25rem;
}

Example

<ReactSketchCanvas
  style={{
    border: "0.0625rem solid #9c9c9c",
  }}
/>

Functions

You can export the sketch as an image or as a svg

Use ref to access the element and call the following functions to export image

Props	Expected datatype
eraseMode(boolean)	Switch to eraser mode by passing true. You can switch back to pen mode by passing false
clearCanvas()	Clears the canvas.
resetCanvas()	Resets the canvas and clears the undo/redo stack along with it.
undo()	Undo the last action.
redo()	Redo the previous action.
exportImage(imageTypeString)	Accepts an image type as argument (ExportImageType) and returns a Promise which resolves to base64 data url of the sketch.
exportSvg()	returns a Promise which resolves to an inline SVG element.
exportPaths()	returns a Promise which resolves to an instance of CanvasPath.
loadPaths(CanvasPath)	Accepts an CanvasPath exported from exportPaths() and loads it on the canvas.
getSketchingTime()	returns a Promise which resolves the time that user sketched in the canvas (considers only when the user made the strokes or erased the strokes)

Types

type ExportImageType = "jpeg" | "png";

interface Point {
  x: number;
  y: number;
}

interface CanvasPath {
  paths: Point[];
  strokeWidth: number;
  strokeColor: string;
  drawMode: boolean;
  startTimestamp?: number;
  endTimestamp?: number;
}

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Thanks to

• Philipp Spiess' tutorial
• Draws smooth curves, thanks to François Romain's tutorial
• Immer link
• Pepjs link

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