lnmp4000/usp-sketch

Freehand vector drawing component for React using SVG as canvas 🖌️

Freehand vector drawing component for React using SVG as canvas 🖌

     
  

This project was built using Turborepo.

Overview

Features

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

Requirements

• Requires React >= 16.8

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 * as 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 * as 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
width	PropTypes.string	100%	canvas width (em/rem/px)
height	PropTypes.string	100%	canvas width (em/rem/px)
id	PropTypes.string	"react-sketch-canvas"	ID field to uniquely identify a SVG canvas (Supports multiple canvases in a single page)
className	PropTypes.string	""	Class for using with CSS selectors
strokeColor	PropTypes.string	black	Pen color
canvasColor	PropTypes.string	white	canvas color (HTML colors)
backgroundImage	PropTypes.string	''	Set SVG background with image URL
exportWithBackgroundImage	PropTypes.bool	false	Keep background image on image/SVG export (on false, canvasColor will be set as background)
preserveBackgroundImageAspectRatio	PropTypes.string	none	Set aspect ratio of the background image. For possible values check MDN docs
strokeWidth	PropTypes.number	4	Pen stroke size
eraserWidth	PropTypes.number	8	Erase size
allowOnlyPointerType	PropTypes.string	all	allow pointer type ("all"/"mouse"/"pen"/"touch")
onChange	PropTypes.func		Returns the current sketch path in CanvasPath type on every path change
onStroke	PropTypes.func		Returns the the last stroke path and whether it is an eraser stroke on every pointer up event
style	PropTypes.object	false	Add CSS styling as CSS-in-JS object
svgStyle	PropTypes.object	{}	Add CSS styling as CSS-in-JS object for the SVG
withTimestamp	PropTypes.bool	false	Add timestamp to individual strokes for measuring sketching time
readOnly	PropTypes.bool	false	Disable drawing on the canvas (undo/redo, clear & reset will still work.)

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

Methods

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

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