react-img-markup

React Img Markup

React pattern based library for creating markup on images.

Installation & Usage

Install package:

npm i react-img-markup

or

yarn add react-img-markup

Hook API

*Note: react-img-markup supports a hooks API and a render-props model API. Scroll futher down the page if you're looking for the render-props documentation.

New to react-img-markup version 2, hooks api allow for a more easily controllable pattern that does not rely on component nesting.

Import useImgMarkup hook and ImgMarkupCanvas component from library:

import { useImgMarkup, ImgMarkupCanvas } from 'react-img-markup';

Call the useImgMarkup hook to initialize the logic for your image annotations, destructure bind from the return value of the hook.

const { bind } = useImgMarkup()

Insert component ImgMarkupCanvas into your React JSX and insert bind using spread operator syntax. This will assign the hook logic to the correct instance of ImgMarkupCanvas.

<ImgMarkupCanvas {...bind} />

Now pass the image src directly to ImgMarkupCanvas via imgSrc prop.

<ImgMarkupCanvas imgSrc={src} {...bind} />

Voila! Your image markup should now work with the default settings, though there is a lot more you can customize! Next we will show how the useImgMarkup hook allows us to use state values and setters to set different configurations for annotation- in this example, changing the active color.

Destructure activeColor and setActiveColor from the useImgMarkup hook.

const {
  bind,
  activeColor,
  setActiveColor,
} = useImgMarkup()

You can now use these destructured properties from useImgMarkup to control image markup colors via a standard React state-controlled pattern.

<>
  <ImgMarkupCanvas imgSrc={src} {...bind} />
  <select
    value={activeColor}
    onChange={(e) => setActiveColor(e.target.value)}
  >
    <option value='red'>red</option>
    <option value='green'>green</option>
    <option value='#0af'>blue</option>
    <option value='orange'>orange</option>
  </select>
</>

That's the basics! I will give a full and detailed list of the rest of the features react-img-markup supports below. More in-depth examples will be provided in this project's repository.

useImgMarkup hook arguments

• onSave (func, optional) - callback invoked when image is saved. Will pass the uri as parameter: (uri) => {}.
• onImgLoad (func, optional) - callback invoked when image has loaded: () => {}.
• encoderType (string, optional) - determines the format the file will be saved as. default is "jpg" but also accepts "png".
• encoderOptions (number, optional) - A number between 0 and 1 indicating image quality on save. The default is 0.8.
• defaultValues (obj, optional) - pass options to give ImgMarkup default state values when component mounts.
  • type (string) - value for markup type. Includes: "rect", "ellipsis", "line", "arrow", and "text". Default: "rect".
  • color (string) - value for markup color. Can be any CSS color name, hex, or rgba. Default: "red"
  • strokeWidth (number) - value for markup stroke width. Accepts any numerical value. Default: 2
  • fontSize (number) - value for markup font size. Accepts any numerical value. Default: 20
  • text (string) - value for default text shown to user when text element is first created. Default: ""

useImgMarkup hook return values

• activeType (string) - state. The active markup type. Returned values can be: "rect", "ellipsis", "line", "arrow", and "text".
• activeColor (string) - state. The markup active color state.
• activeStrokeWidth (number) - state. The markup active stroke width.
• activeFontSize (number) - state. The markup active stroke font size.
• setActiveType (func) - sets the activeType state. State settable options are: "rect", "ellipsis", "line", "arrow", and "text".
• setActiveColor (func) - sets the activeColor state. Accepts string values.
• setActiveStrokeWidth (func) - sets the activeStrokeWidth state. Accepts number values.
• setActiveFontSize (func) - sets the activeFontSize state. Accepts number values.
• undo (func) - will undo the last markup element the user created.
• deletePath (func) - pass a path id to delete desired path: deletePath(id).
• save (func) - saves the image with the markup. Will pass the uri to onSave when this function is called. Will also return uri if asynchronously await the call.
• activePathId (string) - state. The id of activePath. Will be assigned null if no paths are active.
• imgMarkupModifiers (obj) - react ref. Assign this ref to an element that wraps your modification elements to not lose the selected state when changing shape/text settings.
• paths (obj) - state. Exposing the exact path data to the user.

ImgMarkupCanvas props

• imgSrc (string, required) - the src of the image you would like to add markup to.
• imgStyles (obj, optional) - styles passed to the image element.

Render-props API

This pattern replicates the original render-props API structure of react-img-markup v1. If you're looking to upgrade to v2 and want to make as few changes as possible, this is the way.

Import ImgMarkupRenderProp component from library.

import { ImgMarkupRenderProp } from 'react-img-markup';

Insert the ImgMarkupRenderProp component inside your JSX, passing your image src to the prop imgSrc.

<ImgMarkupRenderProp imgSrc={src} />

By passing a function as a child of ImgMarkupRenderProp, you get access to properties of ImgMarkupRenderProp via the child's callback function parameters. In this case, our active color state value and setter.

<ImgMarkupRenderProp imgSrc={src}>
  {({ activeColor, setActiveColor }) => (
    <select value={activeColor} onChange={(e) => setActiveColor(e.target.value)}>
      <option value='red'>red</option>
      <option value='green'>green</option>
      <option value='blue'>blue</option>
      <option value='orange'>orange</option>
    </select>
  )}
</ImgMarkupRenderProp>

ImgMarkupRenderProp props

• imgSrc (string, required) - the src of the image you would like to add markup to.
• imgStyles (obj, optional) - styles passed to the image.
• onSave (func, optional) - callback invoked when image is saved. Will pass the uri as parameter: (uri) => {}.
• onImgLoad (func, optional) - callback invoked when image has loaded: () => {}.
• encoderType (string, optional) - determines the format the file will be saved as. default is "jpg" but also accepts "png".
• encoderOptions (number, optional) - A number between 0 and 1 indicating image quality on save. The default is 0.8.
• defaultValues (obj, optional) - pass options to give ImgMarkup default state values when component mounts.
  • type (string) - value for markup type. Includes: "rect", "ellipsis", "line", "arrow", and "text". Default: "rect"
  • color (string) - value for markup color. Can be any CSS color name, hex, or rgba. Default: "red"
  • strokeWidth (number) - value for markup stroke width. Accepts any numerical value. Default: 2
  • fontSize (number) - value for markup font size. Accepts any numerical value. Default: 20
  • text (string) - value for default text shown to user when text element is first created. Default: ""

ImgMarkupRenderProp render prop parameter values

• activeType (string) - state. The active markup type. Returned values can be: "rect", "ellipsis", "line", "arrow", and "text".
• activeColor (string) - state. The markup active color state.
• activeStrokeWidth (number) - state. The markup active stroke width.
• activeFontSize (number) - state. The markup active stroke font size.
• setActiveType (func) - sets the activeType state. State settable options are: "rect", "ellipsis", "line", "arrow", and "text".
• setActiveColor (func) - sets the activeColor state. Accepts string values.
• setActiveStrokeWidth (func) - sets the activeStrokeWidth state. Accepts number values.
• setActiveFontSize (func) - sets the activeFontSize state. Accepts number values.
• undo (func) - will undo the last markup element the user created.
• deletePath (func) - pass a path id to delete desired path: deletePath(id).
• save (func) - saves the image with the markup. Will pass the uri to onSave when this function is called. Will also return uri if asynchronously await the call.
• activePathId (string) - state. The id of activePath. Will be assigned `null`` if no paths are active.
• imgMarkupModifiers (obj) - react ref. Assign this ref to an element that wraps your modification elements to not lose the selected state when changing shape/text settings.
• paths (obj) - state. Exposing the exact path data to the user.

Contributions appreciated!

git clone
npm i --legacy-peer-deps
npm run start

This library was built using react-npm-package-boilerplate as a boilerplate.