Recognizers: $1  •  $N  •  $P  •  $P+  •  $Q  •  Impact of $-family
Tools: GECKo  •  GREAT  •  GHoST  •  AGATe

Impact of $-family

Gesture recognition used to be difficult, arcane, and specialized. Then in 2007 came the $1 recognizer and the $-family that followed, making stroke gestures easy to add to any user interface.

The $-family recognizers, of which $1, $N, $P, and $Q are canonical members, along with enhancements Protractor and $P+, have had significant impact on the deployment of gestures in interactive prototypes. The $1 paper, published at ACM UIST 2007, is the 3rd most-cited UIST paper according to the ACM Digital Library. Google Scholar shows the $1 paper being cited ~840 times. Beyond citations, $1 has been re-implemented in scores of projects. Its use has gone beyond its initial intent for stroke-gesture recognition to things like hand-pose recognition.

The $1 paper and its siblings led to numerous follow-ons by other researchers, leading to the "extended $-family" of technologies. All adopt the same philosophy espoused by the original $1 paper: to take what are typically complex, arcane technologies understood only by specialists and make them easy to convey, implement, and deploy on any platform for non-specialists whose objective is quickly enhancing interactivity. Accordingly, the $1 paper began a trend, followed by other $-family publications, of putting the entire pseudocode necessary for implementation directly in their publications.

Beyond academic impact, $1 and the $-family have been rapidly absorbed into industry prototypes. For example:

The extended $-family

$1 and the other canonical $-family recognizers inspired other researchers to develop follow-ons that share the $-family motivation. We and their authors consider the following to be the "extended family" of the $-family recognizers. They are listed in chronological order:

Some examples of the $-family in industry prototypes

The $-family recognizers have been used in industry prototypes. Below are five nice examples:

Some examples of the $-family in others' research projects [Google Scholar for $1]

Many research projects have used the $-family recognizers, especially $1. Below are six projects by others:

$-family implementations by others

Over the years, many developers have sent in their own implementations of our $-family recognizers in various programming languages. We make no representation of the correctness or completeness of these implementations, but offer them here "as is." (Have one to add? Email




Copyright © 2018-2019 Jacob O. Wobbrock. All rights reserved.
Last updated April 15, 2019.