JavaScript
This JavaScript library produces complimentary gradients generated from the top 2 dominant colours in supplied images.

Grade

Demo

Check it out

Install

Download this repo and grab the grade.js file from the /docs/dist folder.

Or install from npm: npm install grade-js

Usage

Recommended HTML structure:

<!--the gradients will be applied to these outer divs, as background-images-->
<div class="gradient-wrap">
    <img src="./samples/finding-dory.jpg" alt="" />
</div>
<div class="gradient-wrap">
    <img src="./samples/good-dinosaur.jpg" alt="" />
</div>

If you have the grade.js in your project, you can include it with a script tag and initialise it like so:

<script src="path/to/grade.js"></script>
<script type="text/javascript">
    window.addEventListener('load', function(){
        /*
            A NodeList of all your image containers (Or a single Node).
            The library will locate an <img /> within each
            container to create the gradient from.
         */
        Grade(document.querySelectorAll('.gradient-wrap'))
    })
</script>

If you've installed from npm, you can use the library like so:

import Grade from 'grade-js'
// initialise as above