A plugin that provides shortcodes for converting images to responsive <picture> elements.

• Installation
• Usage
  • Options
    • ratios
    • sources
    • resize()
    • fallback()
• Example
• License

Installation

# npm
npm i eleventy-plugin-responsive-picture

# yarn
yarn add eleventy-plugin-responsive-picture

Usage

Register the plugin in you .eleventy.js file:

const eleventyResponsivePicturePlugin = require("eleventy-plugin-responsive-picture");

module.exports = (eleventyConfig) => {
  eleventyConfig.addPlugin(eleventyResponsivePicturePlugin, { ...options });
});

In your layout, wrap an <img> tag with {% responsive %}.

For example:

{% responsive %}
<img src="/profile-picture.jpg">
{% endresponsive %}

The <img> will be wrapped with a <picture> element as specified in the configuration options

Options

ratios

Required. Type: number[]

An array of pixel density ratios for the srcset of each <source>. They are applied in the order supplied.

Example:

{
  ratio: [2, 1];
}

sources

Required. Type: { size: number, media?: string, type?: string }[]

A list of <source>s to generate, with the following properties:

• media (string) an optional media query, e.g. (min-width: 1024px)
• size (number) image size in pixels for the corresponding media query, e.g. 824
• type (string) an optional mime type, e.g. image/jpeg

The order of sources is unchanged by the plugin.

resize()

Required. Type: (src: string, size: number, type: string) => string

A function that will return a URL for a resized version of the image.

Example:

{
  resize: (src, size) => `${src}?w=${size}`;
}

fallback()

Optional. Type: (src: string) => string.

A function that returns the URL of the image to use in the "fallback" <img> element. This allows you to serve a resized image by default, rather than a full-size image.

Example:

{
  resize: (src) => `${src}?w=1000`;
}

Example

Plugin registration

eleventyConfig.addPlugin(eleventyNavigationPlugin, {
  ratios: [2, 1],
  sources: [
    { media: "(min-width: 1024px)", size: 824 },
    { media: "(min-width: 768px)", size: 696 },
    { media: "(min-width: 420px)", size: 568 },
    { size: 348 },
  ],
  fallback: (src) => `${src}?w=1000`,
  resize: (src, width) => `${src}?w=${size}`,
});

Template use

{% responsive %}
<img src="./image.jpg" alt="My super cool image" />
{% endresponsive %}

Output:

<picture>
  <source
    media="(min-width: 1024px)"
    srcset="./image.jpg?w=1648 2x, ./image.jpg?w=824 1x"
  />
  <source
    media="(min-width: 768px)"
    srcset="./image.jpg?w=1392 2x, ./image.jpg?w=696 1x"
  />
  <source
    media="(min-width: 420px)"
    srcset="./image.jpg?w=1136 2x, ./image.jpg?w=568 1x"
  />
  <source srcset="./image.jpg?w=696 2x, ./image.jpg?w=348 1x" />
  <img src="./image.jpg?w=1000" alt="My super cool image" />
</picture>

Actual output does not include line breaks

License

This software is released under the MIT License.