bhyde@inmet.UUCP (04/02/86)
Postscript is a programming language. Like any useful programming language it is extensible. Any application that generates a spooling file for a postscript printer will extended the postscript language. Typically this will include adding routines to generate images that are unique to that application's needs; for example rounded rectangles with rounded corners. Postscript programs, or spooling files, are usually represented as printable ascci text. The application's extentions are usually placed in the prolog of the spooling file. The MacIntosh print driver for the laser writer extends the postscript language with a set of Mac specific functions. These are kept in the file Laser Prep, which is usually found in the system folder. If you want to take Mac output to another company's postscript printer then you need to stuff a copy of Laser Prep into the beginning of your spooled laser printer output. PageMaker uses a different "Prep" file from the Mac's usual one. Most sophisticated postscript application can be expected to do so, but other applications may hide the existance of the "Prep" inside the application.