<table width="656">

<tr width="656">

<h1>Interactivity</h1>

<p class="license">This tutorial is for Processing version 1.1+. If you see any errors or have comments, please <a href="https://github.com/processing/processing-docs/issues?state=open">let us know</a>. This tutorial is from the book, <a href="http://www.processing.org/learning/books/#shiffman">Learning Processing</a>, by Daniel Shiffman, published by Morgan Kaufmann Publishers, Copyright &copy; 2008 Elsevier Inc. All rights reserved.</p>

</td>

</tr>

<tr>

The screen forms a bridge between our bodies and the realm of circuits and electricity inside computers. We control elements on screen through a variety of devices such as touch pads, trackballs, and joysticks, but the keyboard and mouse remain the most common input devices for desktop computers.

The computer mouse dates back to the late 1960s, when Douglas Engelbart presented the device as an element of the oN-Line System (NLS), one of the first computer systems with a video display. The mouse concept was further developed at the Xerox Palo Alto Research Center (PARC), but its introduction with the Apple Macintosh in 1984 was the catalyst for its current ubiquity. The design of the mouse has gone through many revisions in the last forty years, but its function has remained the same. In Engelbart’s original patent application in 1970 he referred to the mouse as an “X-Y position indicator,” and this still accurately, but dryly, defines its contemporary use.