DIGITIZING TABLES

One of the main problems with any high-density graphics display is getting external graphics, such as detailed drawings, photographs, etc., into the computer and on the screen. This is understandable when you consider that a screen like the one for Apple contains over 54,000 dots. One nifty way to handle this is with the digitizing table. A digitizing table is a device that looks like a flat board (Fig. 2-23). A special pen is connected to it through a cable. The table contains electronics that allow it to accurately locate the position of the pen and feed this information to the computer. A program provided with the computer uses the pen information to turn on a specific dot on the screen. A digitizing table is used by placing a drawing on the table and tracing it out with the pen, or just moving the pen on the table as though it were a drawing surface.

The table can send either single point to the computer when the pen is pressed or it can send a continual stream of points as it is held down. This allows fast, fluidlike drawing movements.