
APPLE IIGS HP/TABASCO PRINTER DRIVER 1.0 	--		TECHNICAL DESCRIPTION (ERS)

Written by Ben Koning

August 1990



This is a printer driver for the HP DeskJet Plus (2277A).  It is a feature-
reduced printer driver, written in a very short time in order to get a driver out
to the public as soon as possible.

This driver contains all of the features of previous dumb-printer drivers, with
the following important exceptions:

	* No color, and arbitrary grayscale support.  Standard black and standard
		white must exist in standard color palette locations; otherwise, color
		to black/white mapping will be incorrect.
		
	* No landscape mode.
	
	* No draft ("text only") mode.
	
	* No reduction ("66% reduction", "33% reduction", etc) modes.
	
	* The PrPixelMap call does not support printing of a subset of a pixelmap.
		Only the LocInfo structure is considered; the source rect is ignored.



This driver breaks several rules which legitimate drivers must obide by:

	* It has a very minimal feature set.  Portrait only, no reduction modes, only
		one (high) quality mode.  Other printer drivers devote much code space,
		bug risks, and performance degradation in order to provide all permutations
		of features implied by any and all options on the printer.
		
	* It does not support Appletalk.  However, it does go through the print manager
		to access any direct-connect port driver that is installed.
		
	* It does not support color.
	
	* There is no notion of a separate Page Setup and Print Job Dialog.  Whether
		the application calls PrStlDialog or PrJobDialog, the same dialog, which
		includes a minimal set of options, appears.
	
	* It does not support Text/Draft Mode.  This mode is a fallacy; applications
		have no control over it anyway and it is ill-fitting in the toolbox
		environment.  Much code in other printer drivers is devoted to it.
		
	* It does not save up an entire document's PICT definitions just prior to
		playing it back during the PrPicFile call.  Pages are printed at PrClosePage
		time.
		
	* It looks at the internal structure of the PICT definition and attempts to
		relieve the DrawPicture call of the burden of clipping an entire page into
		the imaging buffer.
	
