Between Monitor and Printer

PostScript Drivers. Both Windows and Macintosh use system- wide printer drivers: the component that converts data from the application program into a form the printer can understand is not part of the application, but is integrated into the operating system. Applications can call the functions of such system drivers using a standard programming interface. Windows refers to this as the GDI (Graphics Device Interface) and on the Macintosh it is called Quick-Draw. As these interfaces are responsible for monitor display as well as output to the printer, programmers can very easily make their software ready to print, as in principle they only have to divert the screen display instructions to the printer. The concept of a system- wide driver has several advantages:►A new printer driver can be used by all programs. This means that not only will all applications benefit from an improved version of the driver, but also that they will be able to work with new printer models without being rewritten.►Software developers are relieved of having to write their own printer drivers for each new model.►The standardized printer interface can also be “abused” to utilize application data in other ways. Examples of this include fax drivers which are installed like printer drivers, or the PDF driver (see Chapter 8).