pboivin / flou
PHP responsive images and lazy loading toolbox.
Requires
- php: >=8.0
- league/glide: ^1.0|^2.0
Requires (Dev)
- laravel/pint: ^1.1
- mockery/mockery: ^1.5
- phpstan/phpstan: ^1.8
- phpunit/phpunit: ^9.5
README
Flou is a PHP package integrating Glide (PHP) and vanilla-lazyload (JS). It's optimized to quickly implement lazy loading and responsive images from a local folder of source images.
Features:
- Transform local images on initial page load (does not expose Glide URLs)
- Can leverage custom Glide configurations (e.g. source images on S3)
- Generate responsive HTML for
img
andpicture
elements - Useable with static site generators and in CLI scripts
- Framework agnostic (a set of plain PHP classes)
Requirements:
- PHP >= 8.0
Table of contents:
- Installing
- Getting Started
- Image Transformations
- Image Rendering
- Image Sets (Responsive Images)
- Remote Images
- Examples
- Development
- License
Demo project:
See the flou-jigsaw-demo repository for an example project integrating Flou with the Jigsaw PHP static site generator.
Installing
The package can be installed via Composer:
composer require pboivin/flou
This also installs Glide as a Composer dependency.
You can pull in the vanilla-lazyload library via a CDN:
<script src="https://cdn.jsdelivr.net/npm/vanilla-lazyload/dist/lazyload.min.js"></script>
or via NPM:
npm install --save vanilla-lazyload
Consult the vanilla-lazyload documentation for more installation options.
Getting Started
First, initialize the LazyLoad
JS object. Add the following script to your page template:
<script> document.addEventListener("DOMContentLoaded", () => { new LazyLoad({ elements_selector: ".lazyload", }); }); </script>
Then, initialize the ImageFactory
PHP object with your project-specific configuration:
use Pboivin\Flou\ImageFactory; $flou = new ImageFactory([ 'sourcePath' => '/home/user/my-site.com/public/images/source', 'cachePath' => '/home/user/my-site.com/public/images/cache', 'sourceUrlBase' => '/images/source', 'cacheUrlBase' => '/images/cache', ]);
Configuration
The required options are:
Other options:
Framework Integration
If you're using a framework with a Service Container, you can register the $flou
instance as a singleton for your entire application. This will be your entry point to transform and render images.
Extra JS and CSS
Some examples below require additional JS and CSS. You'll find a more complete sample in the assets directory.
Image Transformations
Transforming source images
Use the image()
method to transform a single image into a low-quality image placeholder (LQIP):
$image = $flou->image('01.jpg');
You can also provide custom Glide parameters for the image transformation:
$image = $flou->image('01.jpg', [ 'w' => 10, 'h' => 10, 'fit' => 'crop', ]);
You'll find all available parameters in the Glide documentation.
As you can see, the default parameters are used to generate LQIP from source images, but you are not restricted to that. You may generate as many transformations as you need from the source image:
$phone = $flou->image('01.jpg', ['w' => 500]); $tablet = $flou->image('01.jpg', ['w' => 900]); $desktop = $flou->image('01.jpg', ['w' => 1300]);
If you're working with responsive images and the srcset
attribute, have a look at the next section (Image Sets).
Default Glide parameters
You can customize the default Glide parameters in the ImageFactory
configuration:
$flou = new ImageFactory([ // ... 'glideParams' => [ 'h' => 10, 'fm' => 'gif', ], ]);
Image objects
The image()
method returns an Image
object, from which you can conveniently access the source image file and the transformed (cached) image file:
$image = $flou->image('01.jpg'); # Source image data: echo $image->source()->url(); # /images/source/01.jpg echo $image->source()->path(); # /home/user/my-site.com/public/images/source/01.jpg echo $image->source()->width(); # 3840 echo $image->source()->height(); # 2160 echo $image->source()->ratio(); # 1.77777778 # Transformed image data: echo $image->cached()->url(); # /images/cache/01.jpg/de828e8798017be816f79e131e41dcc9.jpg ...
Use the toArray()
method to export the image to a plain array:
$data = $image->toArray(); # [ # "source" => [ # "url" => "/images/source/01.jpg", # "path" => "/home/user/my-site.com/public/images/source/01.jpg", # "width" => 3840, # "height" => 2160, # "ratio" => 1.77777778, # ], # "cached" => [ # "url" => "/images/cache/01.jpg/de828e8798017be816f79e131e41dcc9.jpg", # ... # ], # ]
Image resampling
Image resampling is a simple way to reuse a transformed image as the source of another transformation. Use the resample()
method to begin:
$greyscale = $flou->resample('01.jpg', [ 'filt' => 'greyscale', 'w' => 2000, ]);
This is the same as calling image()
, but returns an instance of ResampledImage
instead. The resampled image can then be used again as a source for image()
:
$image = $flou->image($greyscale, ['w' => 50]); # Source image: echo $image->source()->url(); # /images/cache/01.jpg/a50df0a8c8a84cfc6a77cf74b414d020.jpg echo $image->source()->width(); # 2000 ... # Transformed image: echo $image->cached()->url(); # /images/cache/_r/01.jpg/a50df0a8c8a84cfc6a77cf74b414d020.jpg/9a5bdd58bbc27a556121925569af7b0c.jpg echo $image->cached()->width(); # 50 ...
Image Rendering
Rendering single images
The render()
method on the image returns an ImageRender
object, which prepares HTML suitable for the vanilla-lazyload library. Then, img()
is used to render an img
element:
$image = $flou->image('01.jpg'); echo $image ->render() ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']);
See HTML Output
<img class="lazyload w-full" alt="Lorem ipsum" src="/images/cache/01.jpg/de828e8798017be816f79e131e41dcc9.gif" data-src="/images/source/01.jpg" width="3840" height="2160" >
Options passed into img()
are included as HTML attributes on the element. Attribute values are not escaped by default.
Some attributes are automatically generated (e.g. src
, width
, height
, etc.). You can override them with a !
prefix:
echo $image ->render() ->img([ 'class' => 'w-full', 'alt' => 'Lorem ipsum', '!src' => false, ]);
See HTML Output
<img class="lazyload w-full" alt="Lorem ipsum" data-src="/images/source/01.jpg" width="3840" height="2160" >
Render options
The ImageRender
object can be configured to optimize the HTML output:
-
useAspectRatio()
: Prevents content shifting when the LQIP is replaced with the source image:echo $image ->render() ->useAspectRatio() ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']); # or use a custom aspect-ratio: echo $image ->render() ->useAspectRatio(16 / 9) ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']);
See HTML Output
<img class="lazyload w-full" alt="Lorem ipsum" style="aspect-ratio: 1.77777778; object-fit: cover; object-position: center;" ... >
-
usePaddingTop()
: A workaround for older browsers not supporting theaspect-ratio
CSS property:echo $image ->render() ->usePaddingTop() ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']); # or use a custom aspect-ratio: echo $image ->render() ->usePaddingTop(16 / 9) ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']);
See HTML Output
<div class="lazyload-padding" style="position: relative; padding-top: 56.25%;"> <img class="lazyload w-full" alt="Lorem ipsum" style="position: absolute; top: 0; left: 0; width: 100%; height: 100%; object-fit: cover; object-position: center;" ... > </div>
-
useWrapper()
: Wraps the image with an extradiv
and separates the LQIP element from the mainimg
element. This is used to add a fade-in effect when the image is loaded.(Requires additional JS and CSS. See fade-in example.)
echo $image ->render() ->useWrapper() ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']);
See HTML Output
<div class="lazyload-wrapper"> <img class="lazyload w-full" alt="Lorem ipsum" ... > <img class="lazyload-lqip" src="/images/cache/01.jpg/de828e8798017be816f79e131e41dcc9.gif" > </div>
-
useBase64Lqip()
: Inlines a Base64 version of the LQIP in thesrc
attribute of theimg
element. This reduces the number of HTTP requests needed to display a page, at the cost of making the HTML a bit heavier.echo $image ->render() ->useBase64Lqip() ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']);
See HTML Output
<img class="lazyload w-full" alt="Lorem ipsum" src="data:image/gif;base64,R0lGODlhAQABAIABAAAAAP///yH+EUNyZWF0Z..." data-src="/images/source/01.jpg" width="2932" height="2000" >
Default render options
You can set the default render options for all images in the ImageFactory
configuration:
$flou = new ImageFactory([ // ... 'renderOptions' => [ 'aspectRatio' => true, 'wrapper' => true, 'base64Lqip' => true, // ... ], ]);
See Available Options
Noscript variation
Use the noScript()
method to render an img
element without any lazy loading behavior:
echo $image ->render() ->noScript(['class' => 'w-full', 'alt' => 'Lorem ipsum']);
See HTML Output
<img class="lazyload-noscript w-full" alt="Lorem ipsum" src="/images/source/01.jpg" width="2932" height="2000" >
This is used to add a noscript
image fallback. (See Noscript image fallback example)
It can also be used creatively to work on the source image with CSS classes and HTML attributes. (See Browser native lazy loading example)
Image Sets (Responsive Images)
Single source (img
element)
Use the imageSet()
method to transform a source image into a set of responsive images:
$imageSet = $flou->imageSet([ 'image' => '01.jpg', 'sizes' => '(max-width: 500px) 100vw, 50vw', 'widths' => [500, 900, 1300, 1700], ]);
This returns an ImageSet
object, which prepares all variations of the source image. The render()
method on the image set returns an ImageSetRender
instance, as seen before with single images:
echo $imageSet ->render() ->useAspectRatio() ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']);
See HTML Output
<img class="lazyload w-full" alt="Lorem ipsum" style="aspect-ratio: 1.77777778; object-fit: cover; object-position: center;" src="/images/cache/01.jpg/de828e8798017be816f79e131e41dcc9.gif" data-src="/images/cache/01.jpg/b8648e93b40b56d5c5a78acc7a23e3d9.jpg" data-srcset="/images/cache/01.jpg/a50df0a8c8a84cfc6a77cf74b414d020.jpg 500w, /images/cache/01.jpg/1422c06dea2257858f6437b9675fba1c.jpg 900w, /images/cache/01.jpg/1eac615f1a50f20c434e5944225bdd4f.jpg 1300w, /images/cache/01.jpg/b8648e93b40b56d5c5a78acc7a23e3d9.jpg 1700w" data-sizes="(max-width: 500px) 100vw, 50vw" width="1700" height="956" >
Like ImageRender
, you can optimize ImageSetRender
with the same methods:
useAspectRatio()
usePaddingTop()
useWrapper()
useBase64Lqip()
noScript()
Multiple sources (picture
element)
With a similar configuration, imageSet()
also handles multiple source images:
$imageSet = $flou->imageSet([ [ 'image' => 'portrait.jpg', 'media' => '(max-width: 1023px)', 'sizes' => '100vw', 'widths' => [400, 800, 1200], ], [ 'image' => 'landscape.jpg', 'media' => '(min-width: 1024px)', 'sizes' => '66vw', 'widths' => [800, 1200, 1600], ], ]);
Then, the picture()
method is used to render a picture
element:
echo $imageSet ->render() ->picture(['class' => 'my-image', 'alt' => 'Lorem ipsum']);
See HTML Output
<picture> <source media="(max-width: 1023px)" data-sizes="100vw" data-srcset="/images/cache/portrait.jpg/a50df0a8c8a84cfc6a77cf74b414d020.jpg 400w, /images/cache/portrait.jpg/1422c06dea2257858f6437b9675fba1c.jpg 800w, /images/cache/portrait.jpg/de828e8798017be816f79e131e41dcc9.jpg 1200w" > <source media="(min-width: 1024px)" data-sizes="66vw" data-srcset="/images/cache/landscape.jpg/c6f9c52bea237b64cc98fc9f5f3f15c6.jpg 800w, /images/cache/landscape.jpg/fcc882305b523e823c7a24df05045c5a.jpg 1200w, /images/cache/landscape.jpg/a50df0a8c8a84cfc6a77cf74b414d020.jpg 1600w" > <img class="lazyload my-image" alt="Lorem ipsum" src="/images/cache/landscape.jpg/66d1d4a938d99f2b0234e08008af09a8.gif" data-src="/images/cache/landscape.jpg/a50df0a8c8a84cfc6a77cf74b414d020.jpg" width="1600" height="900" > </picture>
See also: Art-directed picture
element example
Multiple formats (picture
element)
The configuration allows multiple image formats for each source:
$imageSet = $flou->imageSet([ 'image' => '01.jpg', 'sizes' => '100vw', 'widths' => [400, 800, 1200, 1600], 'formats' => ['webp', 'jpg'], ]); echo $imageSet ->render() ->picture(['class' => 'my-image', 'alt' => 'Lorem ipsum']);
See HTML Output
<picture> <source type="image/webp" data-srcset="/images/cache/01.jpg/7c7086baa60bb4b3876b14dd577fa9e8.webp 400w, /images/cache/01.jpg/49ada5db20e72d539b611e5d17640d2f.webp 800w, /images/cache/01.jpg/cb48c273b44bd0f00155d4932231fe28.webp 1200w, /images/cache/01.jpg/a50df0a8c8a84cfc6a77cf74b414d020.webp 1600w" data-sizes="100vw" > <source type="image/jpeg" data-srcset="/images/cache/01.jpg/27e8a3f7fb4abe60654117a34f2007e1.jpg 400w, /images/cache/01.jpg/f319ea155d0009a7e842f50fcc020fe3.jpg 800w, /images/cache/01.jpg/cfdad3b69ae3a15ba479aa85868e75f3.jpg 1200w, /images/cache/01.jpg/1422c06dea2257858f6437b9675fba1c.jpg 1600w" data-sizes="100vw" > <img class="lazyload w-full" alt="Lorem ipsum" src="/images/cache/01.jpg/bd0dc309cfc3b71731b2e2df3d6e130b.gif" data-src="/images/cache/01.jpg/1422c06dea2257858f6437b9675fba1c.jpg" width="1600" height="900" > </picture>
Custom Glide parameters
You can provide an array of base Glide parameters as a second argument to imageSet()
:
$imageSet = $flou->imageSet([ 'image' => '01.jpg', 'sizes' => '100vw', 'widths' => [400, 800, 1200, 1600], 'formats' => ['webp', 'jpg'], ], [ 'q' => 80, ]);
You'll find all available parameters in the Glide documentation.
Note: You may use all parameters except w
and fm
, which are automatically generated from the widths
and formats
configuration above.
Remote Images
The base ImageFactory
class is optimized for cases where both source and cached images exist on the local filesystem. The RemoteImageFactory
class was introduced to enable new use-cases:
- Working with remote Glide endpoints
- Integrating with existing Glide Server configurations
This adds support for images stored on remote filesystems, such as Amazon S3.
Configuration
The options for RemoteImageFactory
are:
Glide Endpoint
If you already have a Glide instance setup and publicly accessible, you can hook into it with the following configuration:
$flou = new Pboivin\Flou\RemoteImageFactory([ 'glideUrlBase' => '/glide', // or use a full URL: https://cdn.my-site.com/glide 'glideUrlSignKey' => 'secret', ]); $image = $flou->image('test.jpg'); //...
Glide Server
Alternatively, you can pass in a fully configured Glide Server
object:
// @see https://flysystem.thephpleague.com/docs/adapter/aws-s3-v3/ $sourceFilesystem = new League\Flysystem\Filesystem( new League\Flysystem\AwsS3V3\AwsS3V3Adapter(/* S3 adapter configuration */); ); $server = League\Glide\ServerFactory::create([ 'source' => $sourceFilesystem, 'cache' => '/home/my-site.com/storage/glide-cache', 'base_url' => '/glide', ]); $flou = new Pboivin\Flou\RemoteImageFactory([ 'glideServer' => $server, 'glideUrlSignKey' => 'secret', ]); $image = $flou->image('test.jpg'); //...
If you're using Laravel, you can access the filesystem driver from the Storage
facade:
// @see https://laravel.com/docs/filesystem $sourceFilesystem = Illuminate\Support\Facades\Storage::disk('s3')->getDriver(), //...
Caveats
When using RemoteImageFactory
, it is too costly to fetch remote images to analyze their dimensions. Therefore, rendered images will not include width
and height
attributes. I recommend leveraging useAspectRatio()
with a fixed aspect ratio value if possible.
Similarly, useBase64Lqip()
will return a blank placeholder instead of a Base64 encoded LQIP.
Image resampling is not available for remote images.
Examples
Fade-in image on load
Extra JS and CSS:
<script src="https://cdn.jsdelivr.net/npm/vanilla-lazyload/dist/lazyload.min.js"></script> <script> /** * vanilla-lazyload API reference: * https://github.com/verlok/vanilla-lazyload#options */ document.addEventListener("DOMContentLoaded", () => { new LazyLoad({ elements_selector: ".lazyload", callback_loaded: (el) => { const wrapper = el.closest(".lazyload-wrapper"); if (wrapper) { wrapper.classList.add("loaded"); } } }); }); </script> <style> /* Example styles — adjust to taste */ .lazyload-wrapper { position: relative; overflow: hidden; } .lazyload-wrapper .lazyload-lqip { filter: blur(10px); transform: scale(1.1); position: absolute; top: 0; left: 0; width: 100%; height: 100%; } .lazyload-wrapper.loaded .lazyload-lqip { opacity: 0; transition: opacity 0.5s; transition-delay: 0.5s; } </style>
Usage:
<?= $flou ->image('01.jpg') ->render() ->useAspectRatio() ->useWrapper() ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']); ?>
Art-directed picture
element
CSS:
<style> .my-image { width: 100%; height: auto; aspect-ratio: calc(3 / 4); object-fit: cover; object-position: center; } @media screen and (min-width: 1024px) { .my-image { max-width: 66vw; aspect-ratio: calc(16 / 9); } } </style>
Usage:
<?= $flou->imageSet([ [ 'image' => 'portrait.jpg', 'media' => '(max-width: 1023px)', 'sizes' => '100vw', 'widths' => [400, 800, 1200], ], [ 'image' => 'landscape.jpg', 'media' => '(min-width: 1024px)', 'sizes' => '66vw', 'widths' => [800, 1200, 1600], ], ]) ->render() ->picture(['class' => 'my-image', 'alt' => 'Lorem ipsum']); ?>
Noscript fallback
CSS:
<noscript> <style> .lazyload { display: none; } </style> </noscript>
Usage:
<div> <?= ($image = $flou->image('01.jpg')) ->render() ->img(['class' => 'w-full', 'alt' => 'Lorem ipsum']) ?> <noscript> <?= $image ->render() ->noScript(['class' => 'w-full', 'alt' => 'Lorem ipsum']) ?> </noscript> </div>
Native lazy loading (no JS, with LQIP)
Usage:
<?= ($image = $flou->image('01.jpg')) ->render() ->useAspectRatio() ->noScript([ 'class' => 'w-full', 'alt' => 'Lorem ipsum', 'loading' => 'lazy', 'decoding' => 'async', 'style' => "background-image: url({$image->cached()->url()}); background-size: cover;" ]); ?>
Lazy loaded background image
Usage:
<?php $image = $flou->image('01.jpg'); ?> <div class="lazyload" data-bg="<?= $image->source()->url() ?>" style="background-image: url( <?= $image->cached()->url() ?> ); background-size: cover;" > <!-- ... --> </div>
CLI script
Preprocess all images in a source directory and prepare a JSON inventory file:
<?php require 'vendor/autoload.php'; $flou = new Pboivin\Flou\ImageFactory([ 'sourcePath' => './public/images/source', 'cachePath' => './public/images/cache', 'sourceUrlBase' => '/images/source', 'cacheUrlBase' => '/images/cache', ]); $data = []; foreach (glob('./public/images/source/*.jpg') as $path) { $file = basename($path); echo "Processing image: $file\n"; $data[$file] = [ 'source' => $flou->image($file)->source()->toArray(), 'lqip' => $flou->image($file)->cached()->toArray(), 'responsive' => array_map( fn ($width) => $flou->image($file, ['w' => $width])->cached()->toArray(), [500, 900, 1300, 1700] ), ]; } file_put_contents('./data/images.json', json_encode($data, JSON_PRETTY_PRINT)); echo "Done!\n";
Development
Test suite (phpunit)
composer run test
Static analysis (phpstan)
composer run analyse
Code formatting (pint)
composer run format
License
Flou is open-sourced software licensed under the MIT license.