NAME
	PRD_DUMPRPORTTAGS -- dump the specified RastPort to a printer (V44)

   FUNCTION
	Print a rendition of the supplied RastPort, using the supplied
	ColorMap, position and scaling information, as specified in
	the printer preferences.

   IO REQUEST
	io_Message	mn_ReplyPort set if quick I/O is not possible.
	io_Command	PRD_DUMPRPORT.
	io_Flags	IOB_QUICK set if quick I/O is possible.
	io_RastPort	ptr to a RastPort.
	io_ColorMap	ptr to a ColorMap.
	io_Modes	the 'modes' flag from a ViewPort structure,
			(the upper word is reserved and should be zero).

			If you are running under version 36, or greater
			of graphics.library, it is recommended that
			you fill in "io_Modes" with the ULONG (32-bit)
			value returned from calling:

			ULONG ModeID = GetVPModeID(struct ViewPort *);

			Doing so provides for upwards compatability with
			the new display modes available under V36
			(example: aspect ratio calculations for new
			display modes).

	io_SrcX		x offset into the RastPort to start printing from.
	io_SrcY		y offset into the RastPort to start printing from.
	io_SrcWidth	width of the RastPort to print (from io_SrcX).
	io_SrcHeight	height of the RastPort to print (from io_SrcY).
	io_DestCols	width of the printout in printer pixels.
	io_DestRows	height of the printout in printer pixels.
	io_Special	flag bits
	io_TagList	a list of tags to specify more parameters for the
			dump.

   TAGS
	DRPA_SourceHook	a pointer to struct Hook which is called to read
			the source data. io_RastPort and io_ColorMap are
			ignored and should be NULL.

			The hook is called with object == NULL and message
			is a pointer to struct DRPSourceMsg. It must read
			an array of source data.

			Each pixel of the array is an ULONG of form
			0x00RRGGBB.

			Some printer drivers have set PPCB_NOSTRIPE which
			means they cannot print in stripes. Using
			DRPA_SourceHook is the best way for printing for such
			printers because you can still prepare the printer
			source data in stripes then.

			The Source Hook is always called in the context of
			the printer driver DOS process.

	DRPA_AspectX	the X aspect ratio.
	DRPA_AspectY	the Y aspect ratio. This values overwrites the
			aspect ratio from GfxBase or io_Modes and is used
			for scaling.