Graphics tablet

File:Graphics tablet.jpg

A Wacom Graphire2 graphics tablet.

A graphics tablet (or digitizing tablet) is a computer peripheral device that allows for a relatively simple method of inputting hand-drawn graphics or art into a computer in real time. They typically consist of a large flat surface for drawing on, and an attached "stylus" for drawing on the surface, originally as a part of the electronics, but later simply to provide an accurate but smooth "point".

History and background

Early graphics tablets, known as spark tablets, used a stylus that generated clicks with a spark plug. The clicks were then triangulated by a series of microphones to locate the pen in space. This was a complex and expensive system, and was also sensitive to outside noise.

The first graphics tablet resembling contemporary tablets was the RAND Tablet, also known as the Grafacon (for Graphic Converter), created in 1964. The RAND Tablet used a series of wires running in the horizontal and vertical directions just under the surface of the pad that sent out a small magnetic signal with their location encoded in them. This signal was received by the stylus and converted into location data.

The first home computer graphics tablet was the Koala Pad, a device designed for the Apple II. The Koala was later released for practically all home computers that supported graphics, including the TRS-80 Color Computer, Commodore 64 and Atari 8-bit family. Many competing products were produced; the tablets produced by Atari were generally considered to be of particularly high quality.

Modern graphics tablets operate in a fashion similar to the RAND Tablet, using grids of wires to provide both location and pressure information. In these devices, grids for determining the pen location are separated by a thin insulator. When pressure is applied to the tablet, wires in the grids come into contact at the pressure point. This allows current to flow into one horizontal and out of one vertical wire (or vice-versa), thereby locating the stylus. Pointing device detection is aided by a weak magnetic field projected approximately an inch from the tablet surface.

Graphics tablets are readily available in a variety of sizes, from relatively inexpensive A6 tablets up to full-sized A3 tablets. Contemporary tablets usually use the USB interface.

Uses

General uses

Graphics tablets, because of their stylus-based interface and (in some cases) ability to detect pressure, tilt, and other attributes of the stylus and its interaction with the tablet, are widely considered to offer a very natural way to create computer graphics, especially two-dimensional computer graphics. Indeed, many graphics packages (e.g. Corel Painter, Inkscape, Photoshop, Pixel32, Studio Artist, The Gimp) are able to make use of the pressure (and, in some cases, stylus tilt) information generated by a tablet, by modifying attributes such as brush size, opacity, and color based on data received from the graphics tablet. Tablets are also popular for technical drawings, as one can put a piece of paper on them without interfering with their function.

Finally, tablets are gaining popularity as a replacement for the computer mouse as a pointing device. Advocates cite relief from repetitive strain injury and greater intuitiveness[1].

Examples

In high-end computer graphics systems, the graphics tablet has always been the input device of choice. Some examples are:

• the Crosfield imaging system
• PCB drafting/layout systems
• the Quantel Paintbox

Devices similar to graphics tablets, such as light pen-based systems, have been used to control other types of systems, such as the Fairlight CMI computer musical instrument.

Manufacturers

• Aiptek
• Wacom
• Acecad

Similar devices

Touch screens are operated in similar ways, but they usually use either optical grids or a pressure sensitive film instead, and therefore they do not need a special pointing device.

The development of the Tablet PC is another example of the integration of graphics tablet and screen.

References

• "Repetitive Stress". WACOM Technology United States Website. Aug. 24, 2005. {{cite web}}: Check date values in: |date= (help)CS1 maint: date and year (link)