Vue Visual

Vue 2 image and video loader supporting lazy loading. Visual 2.x is a simplification of Version 1.x with a greater reliance on modern browser features (IntersectionObserver, object-fit, srcset, sizes, etc).

Examples at https://bkwld.github.io/vue-visual.

Installation

Install the package: npm install --save vue-visual or yarn add vue-visual

import Vue from 'vue'
import Visual from 'vue-visual'
Vue.component('visual', Visual)
import 'vue-visual/index.css'

These polyfills are recommended for older browsers:
- IntersectionObserver
- ObjectFit

Usage

See the Storybook.

Props

A list of the component properties that may be set on the Visual component.

Assets

image (string) : The URL of an image to load.
srcset (string) : An img srcset, used in addition to the image. Both are recommended.
webp-srcset (string) : A srcset that will be added to a source inside of a picture element with a type of image/webp.
video (string|array) : A video that is loaded after the image is loaded if the device supports video. If a string, should be the URL to a source video. If an array, a list of video URLs that will be added as difference <source>s.

Size

width (number|string) : This width will be applied to the asset element. If a number, it's assumed to be a px value.
height (number|string) : See width
max-width (number|string) : This value will be applied to the asset element as the css max-width. If a number, it's assumed to be a px value.
sizes (string) : Specify the img sizes attribute.
aspect (number) : Force the Visual to a specific aspect ratio. This works by making the asset position:absolute and then using an inner div with a padding-top set to a percentage.
expand (boolean) : Make the Visual fill it's container via CSS using absolute positioning.

Style

object-fit (string) - Default cover. Like the CSS property.
object-position (string) - Default center center. Like the CSS property.
align (string) - Default center middle.. Used in conjunction with slots to position the slot content. May be any combination of one horizontal (left, center, right) and one vertical (top, middle, bottom) choice, space-delimited.

Loading

preload (boolean) - Requires Nuxt framework. If true will add <link rel="preload"/> tags to the <head> for the image assets.
autoload (boolean) - Default: true. If true, assets are loaded immediately unless lazyload.
lazyload (boolean) - Waits until the Visual enters the viewport to trigger loading. Overrides autoload.
intersection-options (object) - IntersectionObserver options. Used with lazyload and autopause.
placeholder-color - Sets a background color behind the assets. Most useful in conjunction with an aspect value.
transition (string, boolean) - Default: 'vv-fade'. A Vue transition name that is applied when an asset is loaded. Set to an empty string to immediately render assets rather than waiting for loading.

Video

autoplay (boolean) - If true, begins playing immediately.
autopause (boolean) - If true, begins playing when the Visual enters the viewport and stops when it leaves. Overrides autoplay.
loop (boolean) - Sets <video> loop
muted (boolean) - Sets <video> muted
controls (boolean) - Sets <video> controls

Accessibility

alt (string) - Sets the alt attribute or aria-label value, depending on context.

Slots

default: Markup is added after the assets and before the loader
image-source: Adds <source> tags to the <picture> element.
video-source: Adds <source> tags to the <video> element.

Methods

load() - Manually initiate loading.
play() - Tell video to play.
pause() - Tell video to pause.
restart() - Tell video to restart playback from beginning.

Events

loaded:image - Image asset has finished loading
loaded:video - Video asset has finished loading
loaded - All assets hvae loaded

Contributing

Boot up the Storybook with yarn storybook and use that as your HMR friendly dev environment
Use npm version ... to build, tag, and update the poblished storybook

Changes from 1.x

Dropped props:
- poster
- fallback
- per-asset variants for load, etc
Prop changes
- background ➡ object-fit
- background-position ➡ object-position
- fill ➡ expand
Not testing for video support on device
Video playing state not stored in Vue state
Image and video loaded simultenously, not in series
Removed setDefaults for setting default options. See custom-defaults for an example of how to implement this functionality using a functional component.

migrate-1.x.coffee shows an example of a functional component that migrates the old API to the new API.

BKWLD / vue-visual

readme