Virtual Keyboard - Types

Types

On a desktop PC, one purpose of a virtual keyboard is to provide an alternative input mechanism for users with disabilities who cannot use a physical keyboard. Another major use for an on-screen keyboard is for bi- or multi-lingual users who switch frequently between different character sets or alphabets. Although hardware keyboards are available with dual keyboard layouts (for example Cyrillic/Latin letters in various national layouts), the on-screen keyboard provides a handy substitute while working at different stations or on laptops, which seldom come with dual layouts.

The standard on-screen keyboard utility on most windowing systems allows hot key switching between layouts from the physical keyboard (typically alt-shift but this is user configurable), simultaneously changing both the hardware and the software keyboard layout. In addition, a symbol in the systray alerts the user to the currently active layout.

Although Linux supports this fast manual keyboard-layout switching function, many popular Linux on-screen keyboards such as gtkeyboard, Matchbox-keyboard or Kvkbd do not react correctly. Kvkbd for example defines its visible layout according to the first defined layout in Keyboard Preferences rather than the default layout, causing the application to output incorrect characters if the first layout on the list is not the default. Activating a hot-key layout switch will cause the application to change its output according to another keyboard layout, but the visible on-screen layout doesn't change, leaving the user blind as to which keyboard layout he is using. Multi-lingual, multi-alphabet users should choose a linux on-screen keyboard that support this feature instead, like Florence.

Virtual keyboards are commonly used as an on-screen input method in devices with no physical keyboard, where there is no room for one, such as a pocket computer, personal digital assistant (PDA), tablet computer or touchscreen equipped mobile phone. It is common for the user to input text by tapping a virtual keyboard built into the operating system of the device. Virtual keyboards are also used as features of emulation software for systems that have fewer buttons than a computer keyboard would have.

Virtual keyboards can be categorized by the following aspects:

• physical keyboards with distinct keys comprising electronically changeable displays integrated in the keypads
• virtual keyboards with touchscreen keyboard layouts or sensing areas
• optically projected keyboard layouts or similar arrangements of "keys" or sensing areas
• optically detected human hand and finger motions
• virtual keyboards to allow input from a variety of input devices, such as a computer mouse, switch or other assistive technology device.

An optical virtual keyboard was invented and patented by IBM engineers in 2008. It optically detects and analyses human hand and finger motions and interprets them as operations on a physically non-existent input device like a surface having painted keys. In that way it allows to emulate unlimited types of manually operated input devices such as a mouse or keyboard. All mechanical input units can be replaced by such virtual devices, optimized for the current application and for the user's physiology maintaining speed, simplicity and unambiguity of manual data input.

On the Internet, various JavaScript virtual keyboards have been created, allowing users to type their own languages on foreign keyboards, particularly in Internet cafes. Multitouch screens allow the possibility to create virtual chorded keyboards for tablet computers, touchscreens, touchpads and wired gloves.