Implementing Direct-Mode Printing(IM:XP)

Inside Macintosh: QuickDraw GX Printing /: Chapter 4 - Advanced Printing Features / Using Advanced Printing Features

Implementing Direct-Mode Printing
Some printer drivers support direct-mode printing, also known as text job format mode printing, in which the generality of QuickDraw GX printing is traded off for faster output using unique features built into the printer hardware. For example, an ImageWriter II printer contains built-in fonts, and its printer driver can make use of them to provide faster printing of text. The printer driver typically allows the user to choose direct-mode printing in these cases.
To allow printing in a nongraphics mode, you must call the GXSetAvailableJobFormatModes function to inform the printer driver of all the modes that the application supports, such as gxGraphicsJobFormatMode for QuickDraw GX printing, gxTextJobFormatMode for direct-mode printing, and gxPostScriptJobFormatMode for PostScript-only printing.
All applications should support QuickDraw GX printing. Your application might support direct-mode printing by reformatting the document to match the way it will look when printed, or support PostScript-only output by warning the user that the output cannot be retrieved from a print file when printed in this mode.

Note
If you are reformatting the document to match the fonts built into the printer, you must query the printer for the fonts, line lengths, and other information using the GXJobFormatModeQuery function. For more information about the information that can be obtained, see the following section, "Formatting for Text Job Format Mode Printing."
If you want to know the mode in effect after the user dismisses the Page Setup dialog box, you can call GXGetJobFormatMode. To change it, you can call GXSetJobFormatMode.