Pen computing
Pen computing refers to the usage of mobile devices such as wireless tablet PCs, PDAs and GPS receivers. The term can also be used to refer to the usage of any product allowing for mobile communication. An indication of such a device is a stylus, generally used to press upon a graphics tablet or touchscreen, as opposed to using a more traditional interface such as a keyboard, keypad, mouse or touchpad.
Historically, pen computing (defined as pointing device plus handwriting recognition) predates the use of a mouse and graphical display by at least two decades, starting with the Stylator and RAND tablet system of the 1950s and early 1960s.
General techniques of pen computing
Pen computing can be implemented in several ways:
Pointing device:
- The tablet and stylus are used as pointing devices, such as to replace a mouse. Note that whereas a mouse is a relative pointing device -- you use the mouse to "push the cursor around" on a screen -- a tablet is an absolute pointing device -- where you put the stylus is exactly where the cursor goes.
- Note that a finger can be used as the stylus on a touch-sensitive tablet surface, such as with a touchscreen.
Handwriting recognition:
- The tablet and stylus can be used to replace both a mouse and a keyboard, by using the tablet and stylus in two modes:
- Pointing mode: The stylus is used as a pointing device as above.
- Handwriting recognition mode: The strokes made with the stylus are analyzed as a "electronic ink", which recognizes the shapes of the strokes are marks as handwritten characters. The characters are then input as text, as if from a keyboard.
- Different systems have switch modes by different means, e.g.
- by writing in a special area of the tablet for handwriting-recognition mode.
- by pressing a special button on the side of the stylus
- by context, such as treating any marks not recognized as text as pointing input.
- by recognizing a special gesture mark.
Gesture recognition:
- This is the technique of recognizing certain special shapes not as handwritting input, but as an indicator of a special command. For example, a "pig-tail" shape (used often as a proofreader's mark) would indicate a "delete" operation. Depending on the implementation, what is deleted might be the object or text where the mark was made, or the stylus can be used as a pointing device to select what it is that should be deleted.
Actual system tend to combine elements of all these techniques.
The Penpoint OS was a special operating system which incorporated gesture recognition at all levels of the operating system. Prior systems which employed gesture recognition only did so within special applications, such as CAD/CAM applications or text processing.
External links
- The Unknown History of Pen Computing contains a history of pen computing from approximately 1917 to 1992.
- Annotated bibliography of references to handwriting recognition and pen computing
- A number of links to pen computing resources
See Also
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