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Viewer.js

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JavaScript image viewer.

Table of contents

Features

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])

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.

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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

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

button

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

navbar

Specify the visibility of the navbar.

title

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

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

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

container

Container to place the viewer in the modal mode.

Only available when the inline option is set to false.

filter

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

Enable to request full screen when play.

Requires the browser supports Fullscreen API.

inheritedAttributes

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

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

initialViewIndex

Define the initial index of the image for viewing.

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

inline

Enable inline mode.

interval

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

keyboard

Enable keyboard support.

focus

Focus the active item in the navbar when initialized.

Requires the keyboard option set to true.

loading

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

loop

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

Define the minimum width of the viewer.

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

minHeight

Define the minimum height of the viewer.

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

movable

Enable to move the image.

rotatable

Enable to rotate the image.

scalable

Enable to scale the image.

zoomable

Enable to zoom the image.

zoomOnTouch

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

zoomOnWheel

Enable to zoom the image by wheeling the mouse.

slideOnTouch

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

toggleOnDblclick

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

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

transition

Enable CSS3 Transition for some special elements.

zIndex

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

zIndexInline

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

zoomRatio

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

minZoomRatio

Define the min ratio of the image when zooming out.

maxZoomRatio

Define the max ratio of the image when zooming in.

url

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

Shortcut of the ready event.

show

Shortcut of the show event.

shown

Shortcut of the shown event.

hide

Shortcut of the hide event.

hidden

Shortcut of the hidden event.

view

Shortcut of the view event.

viewed

Shortcut of the viewed event.

move

Shortcut of the move event.

moved

Shortcut of the moved event.

rotate

Shortcut of the rotate event.

rotated

Shortcut of the rotated event.

scale

Shortcut of the scale event.

scaled

Shortcut of the scaled event.

zoom

Shortcut of the zoom event.

zoomed

Shortcut of the zoomed event.

play

Shortcut of the play event.

stop

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])

Show the viewer.

Only available in modal mode.

hide([immediate])

Hide the viewer.

Only available in modal mode.

view([index])

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])

View the previous image.

next([loop=false])

View the next image.

move(x[, y = 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])

Move the image to an absolute point.

rotate(degree)

Rotate the image with a relative degree.

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

rotateTo(degree)

Rotate the image to an absolute degree.

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

scale(scaleX[, scaleY])

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)

Scale the abscissa of the image.

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

scaleY(scaleY)

Scale the ordinate of the image.

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

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

Zoom the image with a relative ratio

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

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

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])

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

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

This event fires when the viewer modal starts to show.

Only available in modal mode.

shown

This event fires when the viewer modal has shown.

Only available in modal mode.

hide

This event fires when the viewer modal starts to hide.

Only available in modal mode.

hidden

This event fires when the viewer modal has hidden.

Only available in modal mode.

view

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

viewed

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

move

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

moved

This event fires when a viewer has moved an image.

rotate

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

rotated

This event fires when a viewer has rotated an image.

scale

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

scaled

This event fires when a viewer has scaled an image.

zoom

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

zoomed

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

play

This event fires when the viewer starts to play.

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

stop

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

Contributing

Please read through our contributing guidelines.

Versioning

Maintained under the Semantic Versioning guidelines.

License

MIT © Chen Fengyuan

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