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Collage is a simple-to-use image processing library for Clojure. It's intended to be a drop-in solution for high-level image processing needs. It draws some inspiration from Python's PIL and is somewhat similar to mikera's imagez.


Collage grew out of my own need when I was writing another Clojure application. I wanted to have some high-level image processing functionality available - functions into which I could just pass some BufferedImages and get back transformed BufferedImages. At the time, I resorted to doing Java interop, which is nice, but Clojure is nicer. I also wanted to get more experience with Clojure in general.

Project goals

  • Ease of use
  • Well tested-ness
  • Clean, composable internal API
  • Learn (more idiomatic) Clojure

Documentation generated by Marginalia is available on Github pages.

Available on Clojars.


Using the with-image macro.

(:require [fivetonine.collage.util :as util])
(:require [fivetonine.collage.core :refer :all])

(with-image "/path/to/image.jpg"
            (resize :width 1000)
            (rotate 90)
            (util/save :quality 0.85))

Loads the image at /path/to/image.jpg, resizes it to have width of 1000px (height is computed automatically), rotates 90 degrees clockwise and saves it with 85% quality of the original, overwriting the original.

(:require [fivetonine.collage.util :as util])
(:require [fivetonine.collage.core :refer :all])

(def image (util/load-image "/path/to/image.jpg"))
(with-image image
	        (crop 100 50 200 100)
	        (util/save "/path/to/new-image.jpg" :quality 1.0))

Loads an image at /path/to/image.jpg. With that image, crops a 200px by 100px image out of the original, at the point (100,50) in the original image, saves it with 100% quality at /path/to/new-image.jpg.

Vanilla functions.

Plain ol' functions

(:require [fivetonine.collage.util :as util])
(:require [fivetonine.collage.core :refer :all])

(def image (load-image "/path/to/image.png"))
(util/save (flip image :horizontal))

or using the thread-first macro.

(:require [fivetonine.collage.util :as util])
(:require [fivetonine.collage.core :refer :all])

(-> (load-image "/path/to/image.png") (flip :horizontal) (util/save :progressive true))

WebP support

Collage does not provide support for WebP out of the box. Collage includes all the JVM ImageIO API plumbing (in resources/webp-imageio.jar), but the native binaries are not provided. Note that the webp format is reported as a supported format with ImageIO.getReaderFormatNames(). But when trying to load a .webp image, an exception is thrown as the native binary for actually loading the raw data in is missing.

The main reason for not providing binaries is that I don't want to build and maintain all the versions of all the binaries for all the platforms.

Compiling the binary is fairly straightforward. Some instructions are available in the luciad's webp-imageio repo. This repo includes code that is used in Collage to provide support for WebP. I also compiled the native binary that WebP depends on using the instructions in the same repo.

If you run into problems compiling the binary or getting all the pieces working together, please open an issue and describe the situation.

WebP support is currently tested only on Mac OSX, but it should work on other platforms as well.


Contributions, suggestions and friendly criticism are all welcome.


Copyright © 2013 Karl Sutt

Distributed under the Eclipse Public License either version 1.0.


A clean, minimal image processing library for Clojure




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