Philter is a JS plugin giving you the power to control CSS filters with HTML data attributes. Visit the Demo page for examples.

Since version 1.3.0 Philter comes as vanilla js plugin or npm package. Download the plugin and move the philter directory to your js directory, then include it in your page:

<script src="js/philter/philter.min.js"></script>

or with NPM:

npm install philter

const philter = require('philter')

philter(['index.html', 'post.html'], { tag: true, customFilterDir: '', customFilters: [] } (css, svg) => {
  console.log('CSS: ', css)
  console.log('SVG: ', svg)
})

You can also pass 3 parameters to philter:

• tag - boolean - This enables the 'philter' part in data-philter-. If you don't use any plugins which use data attributes or they won't collide with Philter, you can set this to false to omit this part and shorten your markup.
• customFilterDir - string - Directory where custom filters are stored.
• customFilters - array - Array of custom filter names.

I highly recommend using Philter in Node and use the plugin version only for development and demonstration purposes, since the browser version doesn't support all the listed filters.

First initiate the plugin:

<script>
  new Philter({
    transitionTime: 0.5, // hover transition time
    tag: true // 'philter' in data attributes
  });
</script>

You can pass 3 parameters to Philter:

• transitionTime - The hover transition time of default CSS filters
• tag - This enables the 'philter' part in data-philter-. If you don't use any plugins which use data attributes or they won't collide with Philter, you can set this to false to omit this part and shorten your markup.

philter index.html post.html -c index.html -s index.html

Usage: philter [options] <file ...>

Options:

  -h, --help                     output usage information
  -V, --version                  output the version number
  -n, --no-tag                   No "philter" in data attributes
  -s, --svg <dir>                SVG directory or svg/html file to append to
  -c, --css <dir>                CSS directory or css/html file to append to
  -H, --html                     Pass HTML instead of filenames
  -D, --custom-filter-dir <dir>  Custom SVG filter directory
  -F, --custom-filters <list>    Custom filters

Now you can start using the filters. The plugin uses this kind of syntax format:

data-philter-<filter>="<value>"

or

data-philter-<filter>="<value> <hover-value>"

You give an element the data attribute for a specific filter and then a value for it. You can also add another value that the filter will use when hovering on that element. For example:

<div data-philter-blur="5"></div>

This element would be blured in 5px radius. If we would add another value, like this:

<div data-philter-blur="5 0"></div>

The element would unblur when hovered over with the mouse. With filters that use more than one value you have to specify every value for hover too. You can add more than one filter onto an element by using the same method:

<div data-philter-blur="5 0" data-philter-grayscale="100"></div>

Philter even supports custom SVG filters:

<div data-philter-blur="5 0" data-philter-svg="filter"></div>

Where 'filter' in 'data-philter-svg' attribute is the ID of the filter. Also Philter has pre-built custom filters:

<div data-philter-color="#00ff00 50"></div>

This one would overlay the element with #00ff00 color in 50% opacity. More filters are to come in the near future. You have any suggestions or know a filter that certainly has to be present in Philter? Just contact me or Elephento team.

Here's a list of filters that you can use and their limitations in Philter.

• blur
• grayscale
• hue-rotate
• saturate
• sepia
• contrast
• invert
• opacity
• brightness
• drop-shadow - Requires 4 values. In the browser the 4th value instead of color is opacity 0 to 100%, color is locked to black.
• svg - Custom SVG filter. Requires 1 value - filter ID.
• color - Requires 2 values. Color and opacity.
• vintage - Requires an integer from 1 to 6.
• duotone - Requires 2 values. 2 colors in hex.
• custom - Requires a string - custom filter name.
• anaglyph - Experimental - Requires an anaglyph offset value.

Drop shadow filter in browser supports only black color because with it's already long class it would be even longer with rgba implementation.

There are 6 vintage filters:

• Rises contrast. Brings out details and colors.
• Washes out the image with light brown sepia.
• Raises the brightness and gives a green/cyan look.
• Close to 3 but a bit less brightness and more green.
• Close to 2 but mixed with violet. Gives a sweet/daydream look.
• Grayscale but better (IMO :))

Duotone filter maps shadows and highlights of the image to 2 different colors. First color is mapped to the shadow and second to the highlights. Colors for this filter should be provided in hex format e.g., #123456.

This section contains filters that are experimental i.e. work only in one browser, have image breaking bugs (even though this whole SVG thing is pretty buggy) etc. These filters will be showcased here: Philter experimental.

Anaglyph filter tries to imitate the 3D anaglyph effect that is widely used for 3D images and graphic effects. So far this should work 100% only on Chrome. Also I use feBlend to cut off the offset part which means that the bigger the offset is the more of the image is being cut off the left side.

You can use filters that you wrote by yourself in NPM/CLI version by using the custom tag like this:

data-philter-cutom="<custom-filter-name>"

If using custom filters you must supply the directory where they're stored and custom filter names in the options. The file of the filter must have that name and its id must be that same name.

Philter was developed and tested on Chrome 46+, Firefox 41+, Opera 34+ and Edge 20+. The default CSS filters should be compatible with most versions of browsers that support filters. The custom filters are supported only by Firefox, Chrome and Opera. You may notice glitching on Edge when more than one hover element is on the page and loss of some filters when they are stacked on one element.

This is mainly due to SVG filter limitations or complexities. It may be solved in the future... or it may not.

• On my recent tests with Chrome SVG filters stack with other filters but as always you may encounter bugs.
• SVG filters don't support CSS transitions.
• SVG filters actually know what to do on hover but ^ and you may encounter other bugs (like flickering and so on). Especially on Edge and IE browsers.

I'm working on all sorts of stuff that involves this plugin and doesn't. So please bear with the way I develop Philter. If you have any suggestions ideas or just wanna say something you can send me an email at [email protected] or tweet @baldassertation.

• Gulp (I work with Gulp, so there will be no Grunt here. Sorry.)
• Webpack
• More custom SVG filters

Philter is licensed under MIT License.