Viewer.js

JavaScript image viewer.

• Website
• jquery-viewer - A jQuery plugin wrapper for Viewer.js.

Table of contents

• Features
• Main
• Getting started
• Keyboard support
• Options
• Methods
• Events
• No conflict
• Browser support
• Contributing
• Versioning
• License

Features

• Supports 53 options
• Supports 23 methods
• Supports 17 events
• Supports modal and inline modes
• Supports touch
• Supports move
• Supports zoom
• Supports rotation
• Supports scale (flip)
• Supports keyboard
• Cross-browser support

Main files

dist/
├── viewer.css
├── viewer.min.css   (compressed)
├── viewer.js        (UMD)
├── viewer.min.js    (UMD, compressed)
├── viewer.common.js (CommonJS, default)
└── viewer.esm.js    (ES Module)

Getting started

Installation

npm install viewerjs

In browser:

<link  href="/path/to/viewer.css" rel="stylesheet">
<script src="/path/to/viewer.js"></script>

The cdnjs provides CDN support for Viewer.js's CSS and JavaScript. You can find the links here.

Usage

Syntax

new Viewer(element[, options])

• element

  • Type: HTMLElement
  • The target image or container of images for viewing.

• options (optional)

  • Type: Object
  • The options for viewing. Check out the available options.

Example

<!-- a block container is required -->
<div>
  <img id="image" src="picture.jpg" alt="Picture">
</div>

<div>
  <ul id="images">
    <li><img src="picture-1.jpg" alt="Picture 1"></li>
    <li><img src="picture-2.jpg" alt="Picture 2"></li>
    <li><img src="picture-3.jpg" alt="Picture 3"></li>
  </ul>
</div>

// You should import the CSS file.
// import 'viewerjs/dist/viewer.css';
import Viewer from 'viewerjs';

// View an image.
const viewer = new Viewer(document.getElementById('image'), {
  inline: true,
  viewed() {
    viewer.zoomTo(1);
  },
});
// Then, show the image by clicking it, or call `viewer.show()`.

// View a list of images.
// Note: All images within the container will be found by calling `element.querySelectorAll('img')`.
const gallery = new Viewer(document.getElementById('images'));
// Then, show one image by click it, or call `gallery.show()`.

Keyboard support

Only available in modal mode.

• Esc: Exit full screen or close the viewer or exit modal mode or stop play.
• Space: Stop play.
• Tab: Switch the focus state on the buttons in the viewer.
• Enter: Trigger the click event handler on the button.
• ←: View the previous image.
• →: View the next image.
• ↑: Zoom in the image.
• ↓: Zoom out the image.
• Ctrl + 0: Zoom out to initial size.
• Ctrl + 1: Zoom in to natural size.

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Options

You may set viewer options with new Viewer(image, options). If you want to change the global default options, You may use Viewer.setDefaults(options).

backdrop

• Type: Boolean or String
• Default: true

Enable the modal backdrop, specify static for the backdrop that will not close the modal on click.

button

• Type: Boolean
• Default: true

Show the button on the top-right of the viewer.

navbar

• Type: Boolean or Number
• Default: true
• Options:
  • 0 or false: hide the navbar
  • 1 or true: show the navbar
  • 2: show the navbar only when the screen width is greater than 768 pixels
  • 3: show the navbar only when the screen width is greater than 992 pixels
  • 4: show the navbar only when the screen width is greater than 1200 pixels

Specify the visibility of the navbar.

title

• Type: Boolean or Number or Function or Array
• Default: true
• Options:
  • 0 or false: hide the title
  • 1 or true or Function or Array: show the title
  • 2: show the title only when the screen width is greater than 768 pixels
  • 3: show the title only when the screen width is greater than 992 pixels
  • 4: show the title only when the screen width is greater than 1200 pixels
  • Function: customize the title content
  • [Number, Function]: the first element indicate the visibility, the second element customize the title content

Specify the visibility and the content of the title.

The name comes from the alt attribute of an image element or the image name parsed from its URL.

For example, title: 4 equals to:

new Viewer(image, {
  title: [4, (image, imageData) => `${image.alt} (${imageData.naturalWidth} × ${imageData.naturalHeight})`]
});

toolbar

• Type: Boolean or Number or Object
• Default: true
• Options:
  • 0 or false: hide the toolbar.
  • 1 or true: show the toolbar.
  • 2: show the toolbar only when the screen width is greater than 768 pixels.
  • 3: show the toolbar only when the screen width is greater than 992 pixels.
  • 4: show the toolbar only when the screen width is greater than 1200 pixels.
  • { key: Boolean | Number }: show or hide the toolbar.
  • { key: String }: customize the size of the button.
  • { key: Function }: customize the click handler of the button.
  • { key: { show: Boolean | Number, size: String, click: Function }: customize each property of the button.
  • Available built-in keys: "zoomIn", "zoomOut", "oneToOne", "reset", "prev", "play", "next", "rotateLeft", "rotateRight", "flipHorizontal", "flipVertical".
  • Available built-in sizes: "small", "medium" (default) and "large".

Specify the visibility and layout of the toolbar its buttons.

For example, toolbar: 4 equals to:

new Viewer(image, {
  toolbar: {
    zoomIn: 4,
    zoomOut: 4,
    oneToOne: 4,
    reset: 4,
    prev: 4,
    play: {
      show: 4,
      size: 'large',
    },
    next: 4,
    rotateLeft: 4,
    rotateRight: 4,
    flipHorizontal: 4,
    flipVertical: 4,
  },
});

see more for custom toolbar.

className

• Type: String
• Default: ''

Custom class name(s) to add to the viewer's root element.

container

• Type: Element or String
• Default: 'body'
• An element or a valid selector for Document.querySelector

Container to place the viewer in the modal mode.

Only available when the inline option is set to false.

filter

• Type: Function
• Default: null

Filter the images for viewing (should return true if the image is viewable, return false to ignore the image).

For example:

new Viewer(image, {
  filter(image) {
    return image.complete;
  },
});

Note that images without the src attribute set will be ignored by default.

fullscreen

• Type: Boolean or FullscreenOptions
• Default: true

Enable to request full screen when play.

Requires the browser supports Fullscreen API.

inheritedAttributes

• Type: Array
• Default: ['crossOrigin', 'decoding', 'isMap', 'loading', 'referrerPolicy', 'sizes', 'srcset', 'useMap']

Define the extra attributes to inherit from the original image.

Note that the basic attributes src and alt will always inherit from the original image.

initialCoverage

• Type: Number
• Default: 0.9

Define the initial coverage of the viewing image. It must a positive number between 0 (0%) and 1 (100%).

initialViewIndex

• Type: Number
• Default: 0

Define the initial index of the image for viewing.

Also used as the default parameter value of the view method.

inline

• Type: Boolean
• Default: false

Enable inline mode.

interval

• Type: Number
• Default: 5000

The amount of time to delay between automatically cycling an image when playing.

keyboard

• Type: Boolean
• Default: true

Enable keyboard support.

focus

• Type: Boolean
• Default: true

Focus the active item in the navbar when initialized.

Requires the keyboard option set to true.

loading

• Type: Boolean
• Default: true

Indicate if showing a loading spinner when loading the image or not.

loop

• Type: Boolean
• Default: true

Indicate if enabling loop viewing or not.

If the current image is the last one, then the next one to view is the first one, and vice versa.

minWidth

• Type: Number
• Default: 200

Define the minimum width of the viewer.

Only available in inline mode (set the inline option to true).

minHeight

• Type: Number
• Default: 100

Define the minimum height of the viewer.

Only available in inline mode (set the inline option to true).

movable

• Type: Boolean
• Default: true

Enable to move the image.

rotatable

• Type: Boolean
• Default: true

Enable to rotate the image.

scalable

• Type: Boolean
• Default: true

Enable to scale the image.

zoomable

• Type: Boolean
• Default: true

Enable to zoom the image.

zoomOnTouch

• Type: Boolean
• Default: true

Enable to zoom the current image by dragging on the touch screen.

zoomOnWheel

• Type: Boolean
• Default: true

Enable to zoom the image by wheeling the mouse.

slideOnTouch

• Type: Boolean
• Default: true

Enable to slide to the next or previous image by swiping on the touch screen.

toggleOnDblclick

• Type: Boolean
• Default: true

Indicate if toggle the image size between its natural size and initial size when double click on the image or not.

In other words, call the toggle method automatically when double click on the image.

Requires dblclick event support.

tooltip

• Type: Boolean
• Default: true

Show the tooltip with image ratio (percentage) when zooming in or zooming out.

transition

• Type: Boolean
• Default: true

Enable CSS3 Transition for some special elements.

zIndex

• Type: Number
• Default: 2015

Define the CSS z-index value of the viewer in modal mode.

zIndexInline

• Type: Number
• Default: 0

Define the CSS z-index value of the viewer in inline mode.

zoomRatio

• Type: Number
• Default: 0.1

Define the ratio when zooming the image by wheeling the mouse.

minZoomRatio

• Type: Number
• Default: 0.01

Define the min ratio of the image when zooming out.

maxZoomRatio

• Type: Number
• Default: 100

Define the max ratio of the image when zooming in.

url

• Type: String or Function
• Default: 'src'

Define where to get the original image URL for viewing.

If it is a string, it should be one of the attributes of each image element. If it is a function, it should return a valid image URL.

For example:

<img src="picture.jpg?size=160">

new Viewer(image, {
  url(image) {
    return image.src.replace('?size=160', '');
  },
});

ready

• Type: Function
• Default: null

Shortcut of the ready event.

show

• Type: Function
• Default: null

Shortcut of the show event.

shown

• Type: Function
• Default: null

Shortcut of the shown event.

hide

• Type: Function
• Default: null

Shortcut of the hide event.

hidden

• Type: Function
• Default: null

Shortcut of the hidden event.

view

• Type: Function
• Default: null

Shortcut of the view event.

viewed

• Type: Function
• Default: null

Shortcut of the viewed event.

move

• Type: Function
• Default: null

Shortcut of the move event.

moved

• Type: Function
• Default: null

Shortcut of the moved event.

rotate

• Type: Function
• Default: null

Shortcut of the rotate event.

rotated

• Type: Function
• Default: null

Shortcut of the rotated event.

scale

• Type: Function
• Default: null

Shortcut of the scale event.

scaled

• Type: Function
• Default: null

Shortcut of the scaled event.

zoom

• Type: Function
• Default: null

Shortcut of the zoom event.

zoomed

• Type: Function
• Default: null

Shortcut of the zoomed event.

play

• Type: Function
• Default: null

Shortcut of the play event.

stop

• Type: Function
• Default: null

Shortcut of the stop event.

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Methods

All methods allow chain composition.

As there are some asynchronous processes when start the viewer, you should call a method only when it is available, see the following lifecycle:

new Viewer(image, {
  ready() {
    // 2 methods are available here: "show" and "destroy".
  },
  shown() {
    // 9 methods are available here: "hide", "view", "prev", "next", "play", "stop", "full", "exit" and "destroy".
  },
  viewed() {
    // All methods are available here except "show".
    this.viewer.zoomTo(1).rotateTo(180);
  }
});

show([immediate])

• immediate (optional):
  • Type: Boolean
  • Default: false
  • Indicates if show the viewer immediately or not.

Show the viewer.

Only available in modal mode.

hide([immediate])

• immediate (optional):
  • Type: Boolean
  • Default: false
  • Indicates if hide the viewer immediately or not.

Hide the viewer.

Only available in modal mode.

view([index])

• index (optional):
  • Type: Number
  • Default: 0 (inherits from the initialViewIndex option)
  • The index of the image for viewing

View one of the images with the image index. If the viewer is hidden, it will be shown first.

viewer.view(1); // View the second image

prev([loop=false])

• loop (optional):
  • Type: Boolean
  • Default: false
  • Indicate if turn to view the last one when it is the first one at present.

View the previous image.

next([loop=false])

• loop (optional):
  • Type: Boolean
  • Default: false
  • Indicate if turn to view the first one when it is the last one at present.

View the next image.

move(x[, y = x])

• x:

  • Type: Number
  • The moving distance in the horizontal direction.

• y (optional):

  • Type: Number
  • The moving distance in the vertical direction.
  • If not present, its default value is x

Move the image with relative offsets.

viewer.move(1);
viewer.move(-1, 0); // Move left
viewer.move(1, 0);  // Move right
viewer.move(0, -1); // Move up
viewer.move(0, 1);  // Move down

moveTo(x[, y = x])

• x:

  • Type: Number
  • The new position in the horizontal direction.

• y (optional):

  • Type: Number
  • The new position in the vertical direction.
  • If not present, its default value is x.

Move the image to an absolute point.

rotate(degree)

• degree:
  • Type: Number
  • Rotate right: requires a positive number (degree > 0)
  • Rotate left: requires a negative number (degree < 0)

Rotate the image with a relative degree.

viewer.rotate(90);
viewer.rotate(-90);

rotateTo(degree)

• degree:
  • Type: Number

Rotate the image to an absolute degree.

viewer.rotateTo(0); // Reset to zero degree
viewer.rotateTo(360); // Rotate a full round

scale(scaleX[, scaleY])

• scaleX:

  • Type: Number
  • Default: 1
  • The scaling factor to apply on the abscissa of the image
  • When equal to 1 it does nothing.

• scaleY (optional):

  • Type: Number
  • The scaling factor to apply on the ordinate of the image
  • If not present, its default value is scaleX.

Scale the image.

viewer.scale(-1); // Flip both horizontal and vertical
viewer.scale(-1, 1); // Flip horizontal
viewer.scale(1, -1); // Flip vertical

scaleX(scaleX)

• scaleX:
  • Type: Number
  • Default: 1
  • The scaling factor to apply on the abscissa of the image
  • When equal to 1 it does nothing

Scale the abscissa of the image.

viewer.scaleX(-1); // Flip horizontal

scaleY(scaleY)

• scaleY:
  • Type: Number
  • Default: 1
  • The scaling factor to apply on the ordinate of the image
  • When equal to 1 it does nothing

Scale the ordinate of the image.

viewer.scaleY(-1); // Flip vertical

zoom(ratio[, showTooltip[, pivot]])

• ratio:

  • Type: Number
  • Zoom in: requires a positive number (ratio > 0)
  • Zoom out: requires a negative number (ratio < 0)

• showTooltip (optional):

  • Type: Boolean
  • Default: false
  • Indicates whether to show the tooltip.

• pivot (optional):

  • Type: Object
  • Default: null
  • Schema: { x: Number, y: Number }
  • The pivot point coordinate for zooming.

Zoom the image with a relative ratio

viewer.zoom(0.1);
viewer.zoom(-0.1);

zoomTo(ratio[, showTooltip[, pivot]])

• ratio:

  • Type: Number
  • Requires a positive number (ratio > 0)

• showTooltip (optional):

  • Type: Boolean
  • Default: false
  • Indicates whether to show the tooltip.

• pivot (optional):

  • Type: Object
  • Default: null
  • Schema: { x: Number, y: Number }
  • The pivot point coordinate for zooming.

Zoom the image to an absolute ratio.

viewer.zoomTo(0); // Zoom to zero size (0%)
viewer.zoomTo(1); // Zoom to natural size (100%)

// Zoom to 50% from the center of the window.
viewer.zoomTo(.5, {
  x: window.innerWidth / 2,
  y: viewer.innerHeight / 2,
});

play([fullscreen])

• fullscreen (optional):
  • Type: Boolean or FullscreenOptions
  • Default: false
  • Indicate if request fullscreen or not.

Play the images.

stop()

Stop play.

full()

Enter the modal mode.

Only available in inline mode.

exit()

Exit the modal mode.

Only available in inline mode.

tooltip()

Show the current ratio of the image by percentage.

Requires the tooltip option set to true.

toggle()

Toggle the image size between its current size and natural size.

Used by the toggleOnDblclick option.

reset()

Reset the image to its initial state.

update()

Update the viewer instance when the source images changed (added, removed, or sorted).

If you load images dynamically (with XMLHTTPRequest), you can use this method to add the new images to the viewer instance.

destroy()

Destroy the viewer and remove the instance.

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Events

All events can access the viewer instance with this.viewer in its handler.

Be careful to use these events with other components which have the same event names, e.g.: Bootstrap's modal.

let viewer;

image.addEventListener('viewed', function () {
  console.log(this.viewer === viewer);
  // > true
});

viewer = new Viewer(image);

ready

• event.bubbles: true
• event.cancelable: true
• event.detail: null

This event fires when a viewer instance is ready for viewing.

In modal mode, this event will not be triggered until you click on one of the images.

show

• event.bubbles: true
• event.cancelable: true
• event.detail: null

This event fires when the viewer modal starts to show.

Only available in modal mode.

shown

• event.bubbles: true
• event.cancelable: true
• event.detail: null

This event fires when the viewer modal has shown.

Only available in modal mode.

hide

• event.bubbles: true
• event.cancelable: true
• event.detail: null

This event fires when the viewer modal starts to hide.

Only available in modal mode.

hidden

• event.bubbles: true
• event.cancelable: false
• event.detail: null

This event fires when the viewer modal has hidden.

Only available in modal mode.

view

• event.bubbles: true
• event.cancelable: true
• event.detail.index:
  • Type: Number
  • The index of the original image.
• event.detail.image:
  • Type: HTMLImageElement
  • The current image (a clone of the original image).
• event.detail.originalImage:
  • Type: HTMLImageElement
  • The original image.

This event fires when a viewer starts to show (view) an image.

viewed

• event.bubbles: true
• event.cancelable: false
• event.detail: the same as the view event.

This event fires when a viewer has shown (viewed) an image.

move

• event.bubbles: true
• event.cancelable: true
• event.detail.x:
  • Type: Number
  • The new position in the horizontal direction.
• event.detail.y:
  • Type: Number
  • The new position in the vertical direction.
• event.detail.oldX:
  • Type: Number
  • The old position in the horizontal direction.
• event.detail.oldY:
  • Type: Number
  • The old position in the vertical direction.
• event.detail.originalEvent:
  • Type: Event or null
  • Options: pointermove, touchmove, and mousemove.

This event fires when a viewer starts to move an image.

moved

• event.bubbles: true
• event.cancelable: false
• event.detail: the same as the move event.

This event fires when a viewer has moved an image.

rotate

• event.bubbles: true
• event.cancelable: true
• event.detail.degree:
  • Type: Number
  • The new rotation degrees.
• event.detail.oldDegree:
  • Type: Number
  • The old rotation degrees.

This event fires when a viewer starts to rotate an image.

rotated

• event.bubbles: true
• event.cancelable: false
• event.detail: the same as the rotate event.

This event fires when a viewer has rotated an image.

scale

• event.bubbles: true
• event.cancelable: true
• event.detail.scaleX:
  • Type: Number
  • The new scaling factor in the horizontal direction.
• event.detail.scaleY:
  • Type: Number
  • The new scaling factor in the vertical direction.
• event.detail.oldScaleX:
  • Type: Number
  • The old scaling factor in the horizontal direction.
• event.detail.oldScaleY:
  • Type: Number
  • The old scaling factor in the vertical direction.

This event fires when a viewer starts to scale an image.

scaled

• event.bubbles: true
• event.cancelable: false
• event.detail: the same as the scale event.

This event fires when a viewer has scaled an image.

zoom

• event.bubbles: true
• event.cancelable: true
• event.detail.ratio:
  • Type: Number
  • The new (next) ratio of the image (imageData.width / imageData.naturalWidth).
• event.detail.oldRatio:
  • Type: Number
  • The old (current) ratio of the image.
• event.detail.originalEvent:
  • Type: Event or null
  • Options: wheel, pointermove, touchmove, and mousemove.

This event fires when a viewer starts to zoom (in or out) an image.

zoomed

• event.bubbles: true
• event.cancelable: false
• event.detail: the same as the zoom event.

This event fires when a viewer has zoomed (in or out) an image.

play

• event.bubbles: true
• event.cancelable: true
• event.detail: null

This event fires when the viewer starts to play.

You can abort the playing process by calling event.preventDefault().

stop

• event.bubbles: true
• event.cancelable: true
• event.detail: null

This event fires when the viewer starts to stop.

You can abort the stopping process by calling event.preventDefault().

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No conflict

If you have to use another viewer with the same namespace, call the Viewer.noConflict static method to revert to it.

<script src="other-viewer.js"></script>
<script src="viewer.js"></script>
<script>
  Viewer.noConflict();
  // Code that uses other `Viewer` can follow here.
</script>

Browser support

• Chrome (latest)
• Firefox (latest)
• Safari (latest)
• Opera (latest)
• Edge (latest)
• Internet Explorer 9+

Contributing

Please read through our contributing guidelines.

Versioning

Maintained under the Semantic Versioning guidelines.

License

MIT © Chen Fengyuan

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