croustille/twill-image

v1.0.1 2022-02-03 17:34 UTC

README

Twill Image is a package designed to work with Twill to display responsive images easily on your site. It leverages Twill's image processing capabilities and adds modern lazy-loading techniques. It supports responsive images, art direction and fixed width images.

  • <picture> with multiple <source> elements
  • Twill's low-quality placeholder (LQIP)
  • Background-color placeholder
  • Art direction (multiple crops)
  • WebP and JPEG support
  • Lazy load (fade in) image with IntersectionOserver
  • Support native lazy loading with loading='lazy'

Contents

Installation

Install the package to your existing Twill project with Composer.

composer require area17/twill-image

Configuration file

The configuration file contains a few general settings and this is where you can define preset for your images.

Publish config/twill-image.php to your app's config folder.

php artisan vendor:publish --provider="A17\Twill\Image\TwillImageServiceProvider" --tag=config

JavaScript module

You can import the JavaScript module and initialize the lazy loading class in your application.

import { TwillImage } from '../../vendor/area17/twill-image'

document.addEventListener('DOMContentLoaded', function () {
  const lazyloading = new TwillImage()
})

When adding or refreshing content of a page without a reload, you can trigger a recalculation of TwillImage's observers by calling the reset() method. This is an example:

document.addEventListener('page:updated', () => lazyloading.reset());

If you prefer to use a pre-compiled version of the JavaScrip module, you can publish a script twill-image.js to your app's public folder and add a <script> tag to your project.

php artisan vendor:publish --provider="A17\Twill\Image\TwillImageServiceProvider" --tag=js

In a Blade file.

<script src="{{ asset('/twill-image.js') }}"></script>

The JavaScript module is not required. If you prefer to rely only on the browser's native loading attribute, set the js config option to false.

Usage

The Image model

The Image model allows you to interact fluently with a media object.

$image = new A17\Twill\Image\Models\Image($object, $role, $media);

// or using the Facade
$image = TwillImage::make($object, $role, $media);
Argument Type Default Description
$object (Required) A17\Twill\Models\Media A17\Twill\Models\Block object Your Twill module or block object
$role (Required) string Media role
$media A17\Twill\Models\Media null Media instance

Available methods

Once you have created an instance of the Image model, you can interact by using one or chaining many of these methods.

crop

You can specify the crop name by passing it as an argument. By default, the Image model will look for a crop name default and if it isn't availble, it will look for a single crop and select it. If it can't determine the crop, it will result in an error.

$image->crop('listing_card');
width

To set the width of the image, you can use this method. The default is an image of 1000 pixels wide. This is useful if you need to display an image with a fixed width or if you know in advance that you will a larger image than the default.

Note: the width is applied to the "fallback" image (<img src="{{ $image }}">) and to determine the number of image URLs to add to the srcset attribute.

$image->width(1500);
height

You can set the height of the image with this method. Similar to the width method above, it is most useful for fixed-size image. When not used, the height is determined by the aspect ratio of the image and inferred from the width.

$image->height(900);

$image->crop('listing')->width(600)->height(400);
sources

To use mutliples <source> elements, you can pass a array to this method by listing the sources other than the main crop. Each item in the array must have a mediaQuery and a crop key in order to generate the proper srcset. You can pass an optional width and height. This is useful when used with the crop method to set the main image crop. See also Art directed images.

$image->crop('desktop')->sources([
    [
        'mediaQuery' => '(max-width: 400px)', // required
        'crop' => 'mobile', // required
        'width' => 200, // optional
        'height' => 200, // optional
        'srcSetWidths' => [100, 200, 400], // optional
    ],
    [
        'mediaQuery' => '(min-width: 401px) and (max-width: 700px)',
        'crop' => 'tablet',
    ],
]);

Media queries can also be generated from a frontend breakpoints and grid structure file by passing a columns key instead of mediaQuery. You can see the format below.

$image->crop('desktop')->sources([
    [
        'columns' => [
            'md' => 'max',
        ],
        'crop' => 'mobile',
    ],
    [
        'columns' => [
            'md' => 'min',
            'lg' => 'max',
        ],
        'crop' => 'tablet',
    ],
]);
sizes

Use this method to pass a sizes attribute to the model.

$image->sizes('(max-width: 400px) 100vw, 50vw');
columns

As an alternative to the sizes method, Twill Image provides a way to generate the sizes attribute based on a frontend breakpoints and grid structure file. When placing this JSON file at the base folder of your app, the sizes attribute can be generated from passing a series of breakpoints and columns number to this method.

$image->columns([
    'xxl' => 6,
    'xl' => 6,
    'lg' => 8,
    'md' => 8,
    'sm' => 8,
    'xs' => 12,
]);

This would tell how many columns the image will take at each breakpoint in order to generate to proper sizes attribute.

Note: this method will have an effect only when frontend.config.json exists at in base folder of your app.

srcSetWidths

Use this method to give a list a widths to generate the srcset attribute. Without this method, Twill Image will auto generate a series of widths based on the image width.

$image->srcSetWidths([100, 150, 300, 600, 1200, 2000, 2400, 3600, 5000]);
preset

With this method you can use an object to pass a value to any of the above methods. You can also add a preset key to the config config/twill-image.php and pass the name to this method.

// config/twill-image.php

return [
    // ...
    'presets' => [
        'art_directed' => [
            'crop' => 'desktop',
            'width' => 700,
            'sizes' => '(max-width: 767px) 25vw, (min-width: 767px) and (max-width: 1023px) 50vw, 33vw',
            'srcSetWidths' => [350, 700, 1400],
            'sources' => [
                [
                    'crop' => 'mobile',
                    'media_query' => '(max-width: 767px)',
                    'srcSetWidths' => [100, 200, 400],
                ],
                [
                    'crop' => 'tablet',
                    'media_query' => '(min-width: 767px) and (max-width: 1023px)',
                ],
            ],
        ],
    ],
];
// to use this preset from the config file
$image->preset('art_directed');

You can directly pass the full object if you prefer.

$image->preset([
    'crop' => 'desktop',
    'width' => 700,
    'sizes' => '(max-width: 767px) 100vw, (min-width: 767px) and (max-width: 1023px) 50vw, 33vw',
    'sources' => [
        [
            'crop' => 'mobile',
            'media_query' => '(max-width: 767px)',
        ],
        [
            'crop' => 'tablet',
            'media_query' => '(min-width: 767px) and (max-width: 1023px)',
        ],
    ],
]);
render

This method will return the rendered view.

{{-- resources/views/home.blade.php --}}
@php
$image = TwillImage::make($page, 'preview')->preset('art_directed');
@endphp

{!! $image->render() !!}

{{-- with arguments --}}
{!! $image->render([
    'loading' => 'eager',
    'layout' => 'constrained',
]) !!}
toArray

If you need to split the image generation from the render (exposing the Image model data through a REST API for example), use this method to get all attributes as an array.

$previewImage = TwillImage::make($page, 'preview')->preset('art_directed')->toArray();

And use the render method from the facade to render the view.

{{-- resources/views/page.blade.php --}}

<div>{!! TwillImage::render($previewImage) !!}</div>

The facade render method

As seen in the previous section, the image element rendering can be separated from the image attributes generation. You can use the Image model to set up your image and pass the resulting object (or its array format to the render method to output the view).

$previewImage = TwillImage::make($page, 'preview')->toArray();
{!! TwillImage::render($previewImage) !!}

or

<div class="w-1/4">
    {!! TwillImage::render($previewImage, [
        'layout' => 'constrained',
        'width' => 700,
    ]) !!}
</div>

List of arguments

Argument Type Default Description
backgroundColor hex string See config Set placeholder background color
class string Add class(es) to the wrapper element
height int
layout "fullWidth" | "constrained" | "fixed" fullWidth By default, the image will spread the full width of its container element, constrained will apply a max-width and fixed will apply hard width and height value
loading "lazy" | "eager" lazy Set native lazy loading attribute
lqip boolean See config Use LQIP
sizes string The image sizes attributes
width int 1000 Used with layout constrained and fixed
imageStyles array [] Apply styles to placeholder and main img tags (ex.: [['object-fit' => 'contain']]

Examples

{!! TwillImage::make($item, 'preview_image')->sizes('(max-width: 767px) 50vw, 100vw')->render(); !!}

@php
$heroImage = TwillImage::make($item, 'preview_image');
$listingImage = TwillImage::make($item, 'preview_image')->crop('listing');
@endphp

{!! TwillImage::render($heroImage) !!}

{!! TwillImage::render($listingImage) !!}

{!! TwillImage::render($listingImage, [
    'layout' => 'constrained',
    'width' => 400
]) !!}

{!! TwillImage::render($listingImage, [
    'layout' => 'fixed',
    'width' => 100,
    'height' => 150
]) !!}

Configuration

In config/twill-image.php, you can define general options and image presets. A preset informs the Image::preset method which crop to output along other options like responsive sources.

<?php

return [

    'background_color' => '#e3e3e3',

    'lqip' => true,

    'webp_support' => true,

    'presets' => [
        'listing' => [
            'crop' => 'card',
            'width' => 500,
            'sizes' => '25vw',
        ],
        // ...
    ],
];

Presets

See above section about the preset method.

List of options

Argument Type Default Description
background_color string #e3e3e3
lqip boolean true Uses Twill LQIP method to generate responsive placeholder
webp_support boolean true If set to false, the type attribute is omitted from <source> elements
js boolean true If set to false, lazy-loading will simply rely on the image's loading attribute
presets object

Art directed images

To use different crops with media queries, you need to list the other sources in a Image::preset or by passing them to the Image::sources method. The rendered image element with have only the ratio of the main crop and other ratio need to be added with CSS.

Let's say this is your preset art_directed in your config:

    // ...
    'art_directed' => [
        'crop' => 'desktop',
        'sizes' => '(max-width: 767px) 100vw, 50vw',
        'sources' => [
            [
                'crop' => 'mobile',
                'media_query' => '(max-width: 767px)',
            ]
        ],
    ],
    // ...
@php
$image = TwillImage::make($page, 'preview')->preset('art_directed');
@endphp

<div>
    {!! TwillImage::render($image, [
        'class' => 'art-directed'
    ]) !!}
</div>

It will output the image element with the class applied to the container.

<div class="twill-image-wrapper art-directed">...</div>

Define styles for each breakpoint.

.art-directed {
  aspect-ratio: 16 / 9;
}

@media screen and (max-width: 767px) {
  .art-directed {
    aspect-ratio: unset;
  }
}

Frontend breakpoints and grid structure

We provide a way to generate sizes and media attributes by describing the structure of your page in a JSON file frontend.config.json placed at the base of your app. An example is provided frontend.config.json.example.

This file describes the breakpoints, main container widths, number of columns per breakpoints and inner/outer gutters. When this file exists in your project, you can use the columns method on the Image model or the columns key in your preset and sources objects in order to generate dynamically the sizes and media attributes.

columns example

This example assumes that you have the provided frontend.config.json in your app's base_path.

columns preset

// config/twill-image.php

return [
    // ...
    'presets' => [
        'art_directed' => [
            'crop' => 'desktop',
            'columns' => [
                'xxl' => 6,
                'xl' => 6,
                'lg' => 8,
                'md' => 8,
                'sm' => 8,
                'xs' => 12,
            ],
            'sources' => [
                [
                    'crop' => 'mobile',
                    'columns' => [
                        'md' => 'max',
                    ],
                ],
                [
                    'crop' => 'tablet',
                    'columns' => [
                        'md' => 'min',
                        'lg' => 'max',
                    ],
                ],
            ],
        ],
    ],
];

columns output

{{-- to use this preset from the config file and render the image --}}
{!! $image->preset('art_directed')->render() !!}

The image source and fallback would have these sizes and media attributes (the elements have been simplified for clarity):

<picture>
    <source media="(max-width: 767px)" sizes="..." srcset="...">
    <source media="(min-width: 768px) and (max-width: 1023px)" sizes="..." srcset="...">
    <img sizes="
        (max-width: 543px) calc((((100vw - 260px) / 12) * 12) + 220px),
        (min-width: 544px) and (max-width: 767px) calc((((100vw - 312px) / 12) * 8) + 168px),
        (min-width: 768px) and (max-width: 1023px) calc((((100vw - 416px) / 12) * 8) + 224px),
        (min-width: 1024px) and (max-width: 1279px) calc((((100vw - 624px) / 12) * 8) + 336px),
        (min-width: 1280px) and (max-width: 1680px) calc((((100vw - 832px) / 12) * 6) + 320px),
        761px
    " src="...">
</picture>

columns custom class

You can provide your own custom class to be used instead of the one provided. You can create your own service and provide the class name in the config file:

// config/twill-image.php

    // ...
    // default to: A17\Twill\Image\Services\ImageColumns::class
   'columns_class' => MyApp\Services\MyOwnImageColumnsService::class,

];

The service must implement the interface A17\Twill\Image\Services\Interfaces\ImageColumns.

This can also be useful if you simply need to override some of the proprties that are defined in the provided services.

Multiple medias

This is an example when you have multiple medias attached to a single role.

@php
$galleryImages = $item->imageObjects('gallery_image', 'desktop')->map(function ($media) use ($item) {
    return TwillImage::make($item, 'gallery_image', $media);
})->toArray();
@endphp

@if($galleryImages)
    @foreach($galleryImages as $image)
        {!! TwillImage::render($image) !!}
    @endforeach
@endif