Processing (programming language)

Paradigm object-oriented
Designed by Casey Reas, Benjamin Fry
First appeared 2001 (2001)
Stable release
3.2.3 / November 7, 2016 (2016-11-07)
Typing discipline strong
OS Cross-platform
License GPL, LGPL
Filename extensions .pde
Influenced by
Design By Numbers, Java, Logo, OpenGL, PostScript, C

Processing is an open source computer programming language and integrated development environment (IDE) built for the electronic arts, new media art, and visual design communities with the purpose of teaching the fundamentals of computer programming in a visual context, and to serve as the foundation for electronic sketchbooks.

The project was initiated in 2001 by Casey Reas and Benjamin Fry, both formerly of the Aesthetics and Computation Group at the MIT Media Lab. In 2012, they started the Processing Foundation along with Daniel Shiffman, who joined as a third project lead.

One of the aims of Processing is to allow non-programmers to start computer programming aided by visual feedback. The Processing language builds on the Java language, but uses a simplified syntax and a graphics user interface.


Processing Software IDE

A screenshot of the Processing IDE
Stable release
3.2.3 / November 7, 2016 (2016-11-07)
Written in Java, GLSL, JavaScript
Operating system Cross-platform
Type Integrated development environment

Processing includes a sketchbook, a minimal alternative to an integrated development environment (IDE) for organizing projects.

Every Processing sketch is actually a subclass of the PApplet Java class which implements most of the Processing language's features.

When programming in Processing, all additional classes defined will be treated as inner classes when the code is translated into pure Java before compiling. This means that the use of static variables and methods in classes is prohibited unless you explicitly tell Processing that you want to code in pure Java mode.

Processing also allows for users to create their own classes within the PApplet sketch. This allows for complex data types that can include any number of arguments and avoids the limitations of solely using standard data types such as: int (integer), char (character), float (real number), and color (RGB, ARGB, hex).


Hello World

The simplest possible version of a "Hello World" program in Processing is:

//This prints "Hello World." to the IDE console.
void setup() {
       println("Hello world.");

However, due to the more visually-oriented nature of Processing, the following code is a better example of the look and feel of the language.

//Hello mouse.
void setup() {
       size(400, 400);
       background(192, 64, 0);

void draw() {
       line(150, 25, mouseX, mouseY);

United States presidential election map

Output of the following example

The next example creates a map of the results of the 2008 USA presidential election. Blue denotes states won by Barack Obama, and red denotes those won by John McCain. (Note: this map does not show the Nebraska district in which Obama won an elector.)

Processing v3 or above is required to run this example.

PShape usa;
PShape state;
String [] Obama  = { "HI", "RI", "CT", "MA", "ME", "NH", "VT", "NY", "NJ",
	 "FL", "NC", "OH", "IN", "IA", "CO", "NV", "PA", "DE", "MD", "MI",
	 "WA", "CA", "OR", "IL", "MN", "WI", "DC", "NM", "VA" };

String [] McCain = { "AK", "GA", "AL", "TN", "WV", "KY", "SC", "WY", "MT",
	 "ID", "TX", "AZ", "UT", "ND", "SD", "NE", "MS", "MO", "AR", "OK",
	 "KS", "LA" };

void setup() {
  size(950, 600);
  // The file "Blank US Map (states only).svg" can be found at Wikimedia Commons
  usa = loadShape("!Blank_US_Map_(states_only).svg");
  smooth(); // Improves the drawing quality of the SVG

void draw() {
  // Draw the full map
  shape(usa, 0, 0);
  // Blue denotes states won by Obama
  statesColoring(Obama , color(0, 0, 255));
  // Red  denotes states won by McCain
  statesColoring(McCain, color(255, 0, 0));
  // Save the map as image
  saveFrame("map output.png");

void statesColoring(String[] states, int c){
  for (int i = 0; i < states.length; ++i) {
    PShape state = usa.getChild(states[i]);
    // Disable the colors found in the SVG file
    // Set our own coloring
    // Draw a single state
    shape(state, 0, 0);

Processing is not a single language, but rather, an arts-oriented approach to learning, teaching, and making things with code. There are several variants and related projects:

Design By Numbers

Processing was based on the original work done on Design By Numbers project at MIT. It shares many of the same ideas and is a direct child of that experiment.

Wiring, Arduino, and Fritzing

Processing has spawned another project, Wiring, which uses the Processing IDE with a collection of libraries written in the C++ language as a way to teach artists how to program microcontrollers. There are now two separate hardware projects, Wiring and Arduino, using the Wiring environment and language. Fritzing is another software environment of the same sort, which helps designers and artists to document their interactive prototypes and to take the step from physical prototyping to actual product.

Mobile Processing

Another spin-off project, now defunct, is Mobile Processing by Francis Li, which allowed software written using the Processing language and environment to run on Java powered mobile devices. Today some of the same functionality is provided by Processing itself.[1]


Main article: Processing.js

In 2008, John Resig ported Processing to JavaScript using the Canvas element for rendering,[2] allowing Processing to be used in modern web browsers without the need for a Java plugin. Since then, the open source community including students at Seneca College in Toronto have taken over the project.

Processing.js is also used to advocate very basic programming to Students of all ages on Khan Academy by creating drawings and animations. Learners showcase their creations to other learners.


Lauren McCarthy has created p5.js, a native JavaScript alternative to Processing.js that has the official support of the Processing Foundation. McCarthy also teaches an introductory course to p5.js on Kadenze.[3]

Python Mode for Processing, or is a Python interface to the underlying Java toolkit. It was chiefly developed by Jonathan Feinberg, with contributions from James Gilles and Ben Alkov.


iProcessing was built to help people develop native iPhone applications using the Processing language. It is an integration of the Processing.js library and a Javascript application framework for iPhone.


Spde (standing for Scala Processing Development Environment) replaces Processing's reduced Java syntax and custom preprocessor with the off-the-shelf Scala programming language which also runs on the Java platform and enforces some of the same restrictions such as disallowing static methods, while also allowing more concise code, and supporting functional programming.[4][5][6]


Quil (formerly named clj-processing) is a wrapper for Processing in the Clojure language, a Lisp that runs on the Java platform.[7]


In 2005 Reas and Fry won the prestigious Golden Nica award from Ars Electronica in its Net Vision category for their work on Processing.

Ben Fry won the 2011 National Design Award given by the Smithsonian Cooper-Hewitt National Design Museum in the category of Interaction Design. The award statement says:

"Drawing on a background in graphic design and computer science, Ben Fry pursues a long-held fascination with visualizing data. As Principal of Fathom Information Design in Boston, Fry develops software, printed works, installations, and books that depict and explain topics from the human genome to baseball salaries to the evolution of text documents. With Casey Reas, he founded the Processing Project, an open-source programming environment for teaching computational design and sketching interactive-media software. It provides artists and designers with accessible means of working with code while encouraging engineers and computer scientists to think about design concepts."


Processing's core libraries, the code included in exported applications and applets, is licensed under the GNU Lesser General Public License, allowing users to release their original code with a choice of license.

The IDE is licensed under the GNU General Public License.


Originally, Processing had the URL at, because the processing domain was taken. Eventually Reas and Fry acquired the domain. Although the name had a combination of letters and numbers, it was still pronounced processing. They do not prefer the environment being referred to as Proce55ing. Despite the domain name change, Processing still uses the term p5 sometimes as a shortened name (p5 specifically is used, not p55).

See also


  1. "Android - Processing". Retrieved 2013-06-03.
  2. "John Resig - Processing.js".
  3. Introduction to Programming for the Visual Arts with p5.js on Kadenze
  4. "Spde: Spde". Retrieved 2013-08-20.
  5. "Coderspiel / Runaway processing". Retrieved 2013-08-20.
  6. "Coderspiel / Flocking with Spde". Retrieved 2013-08-20.
  7. "quil/quil". GitHub. Retrieved 26 January 2015.


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