Sorry for the short documentation, but this code was just meant to be of personal use and show an example on how to create your own custom imagine-filters in Symfony2.

Just install it as every SF2 package by adding it to your composer.js file and run the update-command or downloading the files and adding the package in your AppKernel class.

Configuration

Here's an example on how to use this custom filter:

liip_imagine:
    filter_sets:
        thumbnail:
            quality: 75
            filters:
                thumbnail: { size: [120, 80], mode: outbound }
                watermark:
                    file: %kernel.root_dir%/Resources/misc/watermark.png
                    placement: { position: center, resize: stretch, space: "10%" }