Editing Dasher (software)

{{Short description|Computer accessibility software}}
{{Infobox software
| name                   = Dasher
| logo                   = [[Image:Dasher logo.svg|48px]]<!-- Image name is enough -->
| logo alt               = 
| screenshot             = Dasher.png<!-- Image name is enough -->
| caption                = Dasher running under Linux
| screenshot alt         = 
| collapsible            = 
| author                 = 
| developer              = The Dasher Project
| released               = <!-- {{Start date and age|YYYY|MM|DD|df=yes/no}} -->
| discontinued           = 
| latest release version = 4.11
| latest release date    = {{Start date and age|2010|3|14|df=yes}}
| latest preview version = 5.0 beta
| latest preview date    = {{Start date and age|2016|04|08|df=yes}}<ref>{{Cite web|url=https://github.com/ipomoena/dasher/releases|title = Releases · dasher-project/Dasher| website=[[GitHub]] }}</ref>
| status                 = 
| programming language   = [[Java (programming language)|Java]], [[C (programming language)|C]] and [[C++]]
| operating system       = [[Cross-platform]]
| platform               = 
| size                   = 
| language               = 
| language count         = <!-- Number only -->
| language footnote      = 
| genre                  = [[Computer accessibility]]
| license                = [[GPL]]
| alexa                  = 
| website                = {{URL|www.inference.phy.cam.ac.uk/dasher/}}
| standard               = 
| AsOf                   = 
}}
'''Dasher''' is an [[input method]] and [[computer accessibility]] tool which enables users to compose text without using a [[Computer keyboard|keyboard]], by entering text on a screen with a [[pointing device]] such as a [[Mouse (computing)|mouse]], [[touch screen]], or mice operated by the foot or head. Such instruments could serve as [[prosthetic devices]] for disabled people who cannot use standard keyboards, or where the use of one is impractical.<ref>{{Cite journal | last1 = Wills | first1 = S. A. | last2 = MacKay | first2 = D. J. C. | author-link2 = David J. C. MacKay| doi = 10.1109/TNSRE.2006.875573 | title = DASHER—An Efficient Writing System for Brain–Computer Interfaces? | journal = IEEE Transactions on Neural Systems and Rehabilitation Engineering | volume = 14 | issue = 2 | pages = 244–246 | year = 2006 | pmid = 16792304 | citeseerx = 10.1.1.63.5063 | s2cid = 185665 }}</ref><ref>{{cite book|author=David J. C. MacKay|title=Information theory, inference, and learning algorithms|url=https://books.google.com/books?id=AKuMj4PN_EMC|access-date=18 December 2011|date=6 October 2003|publisher=Cambridge University Press|isbn=978-0-521-64298-9|page=119}}</ref>

Dasher is [[free and open-source software]], subject to the requirements of the [[GNU General Public License]] (GPL), version 2. Dasher is available for operating systems with [[GTK+]] support, i.e. [[Linux]], [[BSD]]s and other [[Unix-like]] including [[macOS]], [[Microsoft Windows]], [[Pocket PC]], [[iOS]] and [[Android (operating system)|Android]].<ref>Inference Group (University of Cambridge): [http://www.inference.phy.cam.ac.uk/dasher/MobileDasher.html Mobile Dasher]. Accessed 2013-01-17.</ref><ref>[https://web.archive.org/web/20100729145114/http://itunes.apple.com/us/app/dasher/id315473092?mt=8 Dasher for iOS] on iTunes. Accessed 2013-01-17.</ref><ref>[https://play.google.com/store/apps/details?id=dasher.android Dasher for Android] on [[Google Play]]. Accessed 2014-06-04.</ref>

Dasher was invented by [[David J. C. MacKay]] and developed by David Ward and other members of MacKay's Cambridge research group. The Dasher project is supported by the [[Gatsby Charitable Foundation]] and by the [[European Union|EU]] aegis-project.<ref>{{Cite web |url=http://www.aegis-project.eu/ |title=aegis-project |access-date=2013-10-27 |archive-date=2020-12-30 |archive-url=https://web.archive.org/web/20201230164913/http://www.aegis-project.eu/ |url-status=dead }}</ref>

==Design==
For whatever the writer intends to write, they select a letter from ones displayed on a screen by using a pointer, whereupon the system uses a [[probability|probabilistic]] predictive [[scientific modeling|model]] to [[prediction by partial matching|anticipate]] the likely character combinations for the next piece of text, and accord these higher priority by displaying them more prominently than less likely letter combinations. This saves the user effort and time as they proceed to choose the next letter from those offered.  The process of composing text in this way has been likened to an [[arcade game]], as users zoom through characters that fly across the screen and select them in order to compose text. The system learns from experience which letter combinations are the most popular, and changes its display protocol over time to reflect this.

==Features==
The Dasher package contains various architecture-independent data files:
* alphabet descriptions for over 150 languages<ref>{{Cite web|url=http://www.inference.phy.cam.ac.uk/dasher/download/alphabets/|title = Index of /Dasher/Download/Alphabets}}</ref>
* letter colours settings
* training files in all supported languages

{{Portal|Free and open-source software}}

==References==
{{reflist|30em}}

==External links==
{{Commons category|Dasher (software)}}
* {{Official website|www.inference.phy.cam.ac.uk/dasher/}}

[[Category:User interfaces]]
[[Category:User interface techniques]]
[[Category:Pointing-device text input]]
[[Category:Disability software]]
[[Category:Free software programmed in C]]
[[Category:Free software programmed in C++]]
[[Category:Free software programmed in Java (programming language)]]
[[Category:GNOME Accessibility]]
[[Category:Cross-platform free software]]
[[Category:Free and open-source Android software]]