medium-zoom

A JavaScript library for zooming images like Medium

🔬 Playground ・
🔎 Demo ・
📚 Storybook

Contents

- Features
- Installation
- Usage
- API
- Selectors
- Options
- Methods
- Attributes
- Events
- Examples
- Debugging
- Browser support
- Contributing
- License

Features

- 📱 Responsive — _scale on mobile and desktop_
- 🚀 Performant and lightweight — _should be able to reach 60 fps_
- ⚡️ High definition support — _load the HD version of your image on zoom_
- 🔎 Flexibility — _apply the zoom to a selection of images_
- 🖱 Mouse, keyboard and gesture friendly — _click anywhere, press a key or scroll away to close the zoom_
- 🎂 Event handling — _trigger events when the zoom enters a new state_
- 📦 Customization — _set your own margin, background and scroll offset_
- 🔧 Pluggable — _add your own features to the zoom_
- 💎 Custom templates — _extend the default look to match the UI of your app_

Installation

The module is available on the npm registry.

`sh
npm install medium-zoom


or


yarn add medium-zoom
`

###### Download

- Normal
- Minified

###### CDN

- jsDelivr
- unpkg

Usage

> Try it out in the browser

Import the library as a module:

`js
import mediumZoom from 'medium-zoom'
`

Or import the library with a script tag:

`html

`

That's it! You don't need to import any CSS styles.

Assuming you add the data-zoomable attribute to your images:

`js
mediumZoom('[data-zoomable]')
`

API

`ts
mediumZoom(selector?: string | HTMLElement | HTMLElement[] | NodeList, options?: object): Zoom
`

$3

The selector allows attaching images to the zoom. It can be of the following types:

- CSS selectors
- HTMLElement
- NodeList
- Array

`js
// CSS selector
mediumZoom('[data-zoomable]')

// HTMLElement
mediumZoom(document.querySelector('#cover'))

// NodeList
mediumZoom(document.querySelectorAll('[data-zoomable]'))

// Array
const images = [
document.querySelector('#cover'),
...document.querySelectorAll('[data-zoomable]'),
]

mediumZoom(images)
`

$3

The options enable the customization of the zoom. They are defined as an object with the following properties:

| Property | Type | Default | Description |
| -------------- | ------------------------------------- | -------- | --------------------------------------------------------------------------- |
| margin | number | 0 | The space outside the zoomed image |
| background | string | "#fff" | The background of the overlay |
| scrollOffset | number | 40 | The number of pixels to scroll to close the zoom |
| container | string \| HTMLElement \| object | null | The viewport to render the zoom in
Read more → |
| template | string \| HTMLTemplateElement | null | The template element to display on zoom
Read more → |

`js
mediumZoom('[data-zoomable]', {
margin: 24,
background: '#BADA55',
scrollOffset: 0,
container: '#zoom-container',
template: '#zoom-template',
})
`

$3

#### open({ target?: HTMLElement }): Promise

Opens the zoom and returns a promise resolving with the zoom.

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.open()
`

_Emits an event open on animation start and opened when completed._

#### close(): Promise

Closes the zoom and returns a promise resolving with the zoom.

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.close()
`

_Emits an event close on animation start and closed when completed._

#### toggle({ target?: HTMLElement }): Promise

Opens the zoom when closed / dismisses the zoom when opened, and returns a promise resolving with the zoom.

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.toggle()
`

#### attach(...selectors: string[] | HTMLElement[] | NodeList[] | Array[]): Zoom

Attaches the images to the zoom and returns the zoom.

`js
const zoom = mediumZoom()

zoom.attach('#image-1', '#image-2')
zoom.attach(
document.querySelector('#image-3'),
document.querySelectorAll('[data-zoomable]')
)
`

#### detach(...selectors: string[] | HTMLElement[] | NodeList[] | Array[]): Zoom

Releases the images from the zoom and returns the zoom.

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.detach('#image-1', document.querySelector('#image-2')) // detach two images
zoom.detach() // detach all images
`

_Emits an event detach on the image._

#### update(options: object): Zoom

Updates the options and returns the zoom.

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.update({ background: '#BADA55' })
`

_Emits an event update on each image of the zoom._

#### clone(options?: object): Zoom

Clones the zoom with provided options merged with the current ones and returns the zoom.

`js
const zoom = mediumZoom('[data-zoomable]', { background: '#BADA55' })

const clonedZoom = zoom.clone({ margin: 48 })

clonedZoom.getOptions() // => { background: '#BADA55', margin: 48, ... }
`

#### on(type: string, listener: () => void, options?: boolean | AddEventListenerOptions): Zoom

Registers the listener on each target of the zoom.

The same options as addEventListener are used.

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.on('closed', event => {
// the image has been closed
})

zoom.on(
'open',
event => {
// the image has been opened (tracked only once)
},
{ once: true }
)
`

The zoom object is accessible in event.detail.zoom.

#### off(type: string, listener: () => void, options?: boolean | AddEventListenerOptions): Zoom

Removes the previously registered listener on each target of the zoom.

The same options as removeEventListener are used.

`js
const zoom = mediumZoom('[data-zoomable]')

function listener(event) {
// ...
}

zoom.on('open', listener)
// ...
zoom.off('open', listener)
`

The zoom object is accessible in event.detail.zoom.

#### getOptions(): object

Returns the zoom options as an object.

`js
const zoom = mediumZoom({ background: '#BADA55' })

zoom.getOptions() // => { background: '#BADA55', ... }
`

#### getImages(): HTMLElement[]

Returns the images attached to the zoom as an array of HTMLElements.

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.getImages() // => [HTMLElement, HTMLElement]
`

#### getZoomedImage(): HTMLElement

Returns the current zoomed image as an HTMLElement or null if none.

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.getZoomedImage() // => null
zoom.open().then(() => {
zoom.getZoomedImage() // => HTMLElement
})
`

$3

#### data-zoom-src

Specifies the high definition image to open on zoom. This image loads when the user clicks on the source image.

`html

`

$3

| Event | Description |
| ------ | --------------------------------------------------- |
| open | Fired immediately when the open method is called |
| opened | Fired when the zoom has finished being animated |
| close | Fired immediately when the close method is called |
| closed | Fired when the zoom out has finished being animated |
| detach | Fired when the detach method is called |
| update | Fired when the update method is called |

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.on('open', event => {
// track when the image is zoomed
})
`

The zoom object is accessible in event.detail.zoom.

Examples

Trigger a zoom from another element

`js
const button = document.querySelector('[data-action="zoom"]')
const zoom = mediumZoom('#image')

button.addEventListener('click', () => zoom.open())
`

Track an event (for analytics)

You can use the open event to keep track of how many times a user interacts with your image. This can be useful if you want to gather some analytics on user engagement.

`js
let counter = 0
const zoom = mediumZoom('#image-tracked')

zoom.on('open', event => {
console.log("${event.target.alt}" has been zoomed ${++counter} times)
})
`

Detach a zoom once closed

`js
const zoom = mediumZoom('[data-zoomable]')

zoom.on('closed', () => zoom.detach(), { once: true })
`

Attach jQuery elements

jQuery elements are compatible with medium-zoom once converted to an array.

`js
mediumZoom($('[data-zoomable]').toArray())
`

Create a zoomable React component

Using React hooks

`js
import React from 'react'
import mediumZoom from 'medium-zoom'

function ImageZoom({ zoom, src, alt, background }) {
const zoomRef = React.useRef(zoom.clone({ background }))

function attachZoom(image) {
zoomRef.current.attach(image)
}

return
}

function App() {
const zoom = React.useRef(mediumZoom({ background: '#000', margin: 48 }))

render() {
return (

)
}
}
`

Using React classes

`js
import React, { Component } from 'react'
import mediumZoom from 'medium-zoom'

class ImageZoom extends Component {
zoom = this.props.zoom.clone({
background: this.props.color,
})

attachZoom = image => {
this.zoom.attach(image)
}

render() {
return (

)
}
}

class App extends Component {
zoom = mediumZoom({ background: '#000', margin: 48 })

render() {
return (

)
}
}
`

You can see more examples including React and Vue, or check out the storybook.

Debugging

The zoomed image is not visible

The library doesn't provide a z-index value on the zoomed image to avoid conflicts with other frameworks. Some frameworks might specify a z-index for their elements, which makes the zoomed image not visible.

If that's the case, you can provide a z-index value in your CSS:

`css
.medium-zoom-overlay,
.medium-zoom-image--opened {
z-index: 999;
}
`

Browser support

| IE | Edge | Chrome | Firefox | Safari |
| --------------- | --------------- | ------ | ------- | ------ |
| 10\ | 12\ | 36 | 34 | 9 |

\* _These browsers require a template polyfill when using custom templates_.

Cross-browser testing is sponsored by

Contributing

- Run yarn to install Node dev dependencies
- Run yarn start to build the library in watch mode
- Run yarn run storybook` to see your changes at http://localhost:9001

Please read the contributing guidelines for more detailed explanations.

_You can also use npm._

License

MIT © François Chalifour