Window Size and Full Screen for Processing 2.0

Casey Reas edited this page Sep 17, 2015 · 1 revision

This page is for Processing 2, and covers things that have vastly improved in Processing 3. If you're interested in this information, use Processing 3 instead! This page will be updated someday when we have a moment.

This page covers window sizing with sketches as well as Present (full screen) mode. In Processing 2.0 (starting with alpha 6), there are several improvements and changes to how full screen is handled, as well as much-improved multiple monitor support.

Making Sketches Resizable

This section only pertains to the desktop version of Processing (not JavaScript or Android), because it's the only one to use windows and frames.

It's possible to make the sketch window resizable. To do this, use the following:

void setup() {
  size(400, 400);  // size always goes first!
  if (frame != null) {

This is not enabled by default because most sketches won't behave well when resized. If a sketch is running inside a web browser, the frame variable will be null.

You can also change the size of the window using the Java method frame.setSize(w, h). Note that you must first set the frame to be resizable.

Running at Full Screen

Just use Sketch → Present and your sketch will run in Full Screen mode.

The displayWidth and displayHeight variables

The displayWidth and displayHeight variables contain the width and height of the screen where the sketch was launched. So to run a sketch that uses the full width and height of the screen, use the following:

void setup() {
  size(displayWidth, displayHeight);

You'll still need to use Present to start the sketch, otherwise the window will have a frame around it, unless you use sketchFullScreen(), described below.

Note that if you move the sketch to another display while it's running, these variables will not update.

In Processing 1.x, an undocumented feature was the presence of screen.width and screen.height. We didn't handle these properly, and they don't fit with the rest of the API (plus they use a class that's not available on Android) so we've removed them.

In Ubuntu Linux under Unity, the default desktop environment, it's often not possible to cover the screen completely with your Processing sketch. You can use a second desktop environment which does full screen just fine.

The sketchFullScreen() method

Adding this method to your code will automatically start your sketch in full screen mode, without having to use Sketch → Present.

boolean sketchFullScreen() {
  return true;

By using this mode, Processing doesn't have to guess whether you're going to run full screen, which can simplify things a little.

Full Screen Exclusive Mode

Full Screen Exclusive Mode (FSEM) has been removed in 2.0. It was prone to causing bugs and we instead added code (from Hansi Raber, thank you!) to hide the menu bar on Mac OS X so that full screen could be achieved without FSEM.

Disabling Full Screen Mode

You can use the Java method frame.setSize(w, h) to change the size of the window, even one that has started at full screen. However, this window will not have a title bar. It's just too problematic and prone to bugs to toggle between the two types of windows (full screen with no extra edges, and a smaller window with title bar and grow box). I have enough nights that I wake up thinking about Processing bugs that I don't need to add these to my list.

Using Multiple Monitors

A lot of effort has gone into fixing up support for multiple displays in 2.0.

By default, a full screen application doesn't cover multiple displays. This is often the preferred solution (for instance, when coding on one monitor and displaying on another). In some cases (usually involving OpenGL), using a single sketch across multiple displays may cause it to run more slowly. This depends on the graphics card, drivers, etc. and is out of our control.

“Run sketches on display” option in Preferences

A new option has been added to the Preferences window that sets the display where sketches are initially placed. As usual, if the sketch window is moved, it will re-open at the same location, however when running in Present (full screen) mode, the display selected here will always be used.

When exporting an application, that display preference will be saved into the exported application.

For the technically inclined, this is implemented by using the --full-screen and --display=N command line parameters for PApplet.

Running a sketch across multiple displays

If you want Present to to use multiple monitors set your size() command to specify the full width and height of the available displays. This can be tricky because multiple displays are often different sizes, or their positions have negative values. There isn't a good way for us to implement this automatically, because there are an infinite number of ways that it can go wrong (which would lead to a similarly infinite stream of bug reports).

sketchWidth() and sketchHeight() methods

Similar to what's happening on Android, it's often better to simply add methods to your sketch that return the sketch width and height. This is the most error-free way to set up a sketch. So for a sketch that reads:

  void setup() {
    size(displayWidth, displayHeight, P3D);

That can instead be written as:

  void setup() {

  public int sketchWidth() {
    return displayWidth;

  public int sketchHeight() {
    return displayHeight;

  public String sketchRenderer() {
    return P3D; 

This helps to avoid the behind-the-scenes magic of restarting the sketch when the renderer is changed, for instance.

We don't require these methods on the desktop version of Processing (yet) because it's tedious, however we may in the future for those using Eclipse or other environments (inside the PDE, the size() command will automatically add them).

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