dasher - graphical predictive text entry system


R dasher


Dasher is an information-efficient text-entry interface, driven by natural continuous pointing gestures. Dasher is a competitive text-entry system wherever a full-size keyboard cannot be used.


dasher takes the following options:

R -a

    Application style. STYLE can be any of

R traditional The default is whatever was specified on the previous invocation of Dasher, or traditional when Dasher is started for the first time.

R -?

    Describe command line options.


    Describe the options available with \fB--options\FR.

R -o

    Override stored options. Options values are remembered for subsequent invocations of Dasher.


The main Dasher interface is a window with a blank background containing a column of letters on the right hand side. Click the mouse button to start. When the pointer is to the right of the crosshair the screen will zoom towards the point underneath the mouse pointer. To select a letter, move the mouse pointer into it and watch how it zooms underneath the crosshair. A new column of letters will appear. Staying within the box for the selected letter, move the pointer over one of these letters to select it as the next letter. Moving the mouse pointer to the left of the crosshair, or outside of the box for previously selected letters, allows you to change previously selected letters.

6. Application Styles


    Dasher displays an edit box above the main window. Text entered via Dasher will appear in the edit box allowing the text to be edited directly.


    The edit box is not displayed. Dasher runs without focus and the text goes into whatever window does have focus. This way you can use it more practically to run your desktop. \".TP \".B compose \" Don't know.


    dasher expands to the entire screen.


7.1. File

New Clear the edit box and associate a random filename with it.

Open Read a text file into the edit box for further editing.

Save Save the contents of the edit box to its associated file.

Save as Save the contents of the edit box to a selected file.

Append to file Add the contents of the edit box to the end of a selected file.

Import training text Use a file to further improve Dasher's prediction of the next letters to present (for instance, a training file containing scientific terms to add to the initial English training). Training files must be UTF-8 encoded.

Quit Exit Dasher.

7.2. Edit

Cut Remove the highlighted text from the edit box and copy it to the clipboard.

Copy Copy the highlighted text from the edit box to the clipboard but don't remove it.

Paste Paste the contents of the clipboard into the edit box at the position of the cursor.

Copy all Copy the entire contents of the edit box to the clipboard.

Select all Highlight all of the text in the edit box.

7.3. Options

Preferences Opens the preferences dialog. \".SM \".B "THE PREFERENCES DIALOG"

Edit font \"Choose the font used in the edit box \"

Dasher font \"Choose the font used in the Dasher canvas \"

Dasher font size \"Choose the size of the font used in the Dasher canvas \"

Reset fonts \"Reset the fonts back to the defaults \"

Enter text into other windows \"Make Dasher enter text into the currently focused window. Requires Dasher to \"have been built with \".B--with-a11y. \"Note that some languages will only work correctly if XFree 4.0.2 or higher is \"being used. \"

Control mode \"Provides a control node at the bottom of the screen. This allows various tasks \"to be performed inside Dasher, such as editing the text written, speaking \"entered text and stopping or pausing Dasher. If compiled with \".B--with-a11y \"and using a desktop supporting the ATK accessibility framework, compliant \"applications will have their menu trees exported to Dasher and these may be \"accessed via this node.

7.4. Help

About Dasher Display information about the current version of Dasher


The preferences dialog is split into several panes.

8.1. Alphabet

Choose a different alphabet. Dasher will automatically retrain itself if the alphabet specified training file is present.

8.2. Colour

Choose a different colour scheme.

8.3. Control

Alter various control options

One dimensional mode Map the Y position of the mouse to a 2 dimensional position on the Dasher canvas (useful for limited mobility users)

Eyetracker mode Similar to one dimensional mode, but behaves normally except at the right-hand side of the canvas. Designed for eyetracker users.

Start on left mouse button \" The left mouse button will toggle Dasher between running and paused state \"

Start on space bar \" The space bar will toggle Dasher between running and paused state \"

Start with mouse position \" When paused, Dasher will display a red box. If the pointer is held in the red \" box until a yellow box appears, and then in the yellow box until it vanishes, \" Dasher will start. This allows users with no button input to start and stop \" Dasher. \"

Copy all on stop \" Toggle whether the current text is automatically copied to the clipboard when \" Dasher is stopped \"

Speak on stop \" Toggle whether the newly entered text should be spoken when Dasher is stopped. \" Requires \" .B --with-speech \" to have been used during Dasher configuration and building. \"

Pause outside window \" Toggle whether Dasher pauses if the mouse cursor is moved outside the Dasher \" window \" .SS View \"

Orientation \" Change the relative position of the letters to the crosshairs. \" .B Alphabet Default \" will allow alphabets to set this automatically. \"

Show toolbar \" Toggle whether or not the row of buttons at the top of the window is displayed \"

Show speed slider \" Toggle whether or not the speed slider at the bottom of the window is displayed \"

Show mouse position \" Toggle whether Dasher should draw a box showing the logical position of the \" mouse cursor \"

Draw line between crosshairs and mouse \" Toggle whether Dasher should draw a line between the crosshairs and the logical \" mouse position \"

Draw box outlines \" Toggle whether Dasher should draw a box outline around every box it draws \"

Change colour scheme automatically \" Alphabets may provide a preferred colour scheme. If this option is enabled, \" Dasher will automatically change to it. \" \" .SS Advanced \"

Smoothing \" The greater the smoothing value, the greater the uniformity of the box sizes. \" This will reduce the predictive capabilities of Dasher, and so may reduce \" writing speed. \"

Timestamp new files \" Include the time at which a file is saved in the filename \"

Distance from centreline for start on mouse position \" Controls the distance from the centre of the Dasher screen that the mouse \" position start boxes will appear. \"

Number of pixels that should cover the entire y range \" Controls how many pixels of input should correspond to complete coverage of \" the Dasher canvas. Only used in one dimensional mode.


Dasher requires that training files be in the UTF-8 format, whereas most text files are likely to be in ISO-8859 format. This doesn't matter for plain text, but accented characters are encoded differently. In order to convert them, use the

R iconv (1) program. For instance, if your training file is in ISO-8859-1 format (Western European), run

iconv -f ISO-8859-1 -t UTF-8 trainingfile >newtrainingfile



    Directory containing system-wide configuration files.


    Directory containing user specific configuration files.

Dasher will utilise files of the following form from both of these directories:

  • alphabet. ALPHABET .xml
        The files defining the alphabets available to Dasher.
  • colour. SCHEME .xml
        The files defining the colour schemes available to Dasher.
  • training_ LANGUAGE* .txt
        Files containing the training data used by Dasher. These are UTF-8 encoded text and should contain a representative sample of the relevant language. User specific training files can be used to augment system wide data.

Refer to the Dasher manual for more information regarding the format and editing of these files.


The Dasher Project <>.


The Dasher project web page is .URL http://www.inference.phy.cam.ac.uk/dasher/