COMMENT ⊗   VALID 00005 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	DVIDD is a program to display a DVI file (the output of TeX) on a Data
C00004 00003	DVIDD commands.
C00007 00004	Extended commands.
C00009 00005	Further details.
C00013 ENDMK
C⊗;
DVIDD is a program to display a DVI file (the output of TeX) on a Data
Disc screen.  To run DVIDD, type

	.r dvidd;filename

where "filename" is the name of your DVI file (extension ".DVI" is optional).
The following optional switches may be used in the command line, after the
filename:

	/nP	Begin displaying at page n
	/M	Use the magnification in the DVI file
	/-M	Use 1440 instead of the magnification in the DVI file
		(this is currently the default setting)
	/nM	Use n instead of the magnification in the DVI file
	/-F	Do not use preloaded fonts (see below)
	/-B	Do not draw boxes around characters whose dimensions
		are read from .TFM files (see below)
	/-G	Do not show gray rectangles for characters whose dimensions
		are read from .TFM files (see below)

Once DVIDD has read the necessary fonts, it will begin displaying the first
page of the file (or a different page requested by the /P switch), and you
can then move around using commands described in the next section.

DVIDD commands.

While running the program, you may use the following commands.  <Control>
and <meta> are shown as "α" and "β", and "#" means any string of digits.
This set of commands has been made to resemble those of E as much as
possible, except that you do not usually need to use the <control> key.

	<form>	Go forward (about 3/4 of a screenful)
	#<form> Go forward # windowfuls
	0<form> Go forward 1/2 window
	α<form> Go forward, changing pages if necessary
	<vt>	Go back
	#<vt>	Go back # windowfuls
	0<vt>	Go back 1/2 window
	α<vt>	Go back, changing pages if necessary
	←	Move text left (about 3/4 of a screenful)
	→	Move text right (about 3/4 of a screenful)
	`	Move text left (about 1/16 of a screenful)
	'	Move text right (about 1/16 of a screenful)
	B	Glitch screen up from bottom
	#B	Glitch sceen up # times from bottom
	E	Exit from the program
	L	Go to the top of the page
	∞L	Go to the bottom of the page
	#L	Show portion of page including the #% point
	P	Go to the next page
	+P	Go to the next page
	-P	Go to the previous page
	#P	Go to page #
	+#P	Go forward # pages
	-#P	Go back # pages
	T	Glitch screen down from top
	#T	Glitch screen down # times from top
	V	Refresh display
	βV	Clear and refresh display
	<alt>	Abort partially typed command
	ε	Edit a file with E
	λ	Edit a file with E, readonly mode
	X	Perform an eXtended command (see below)
	?	Display partial list of commands 

Extended commands.

The X command (with or without <control> and <meta> prefix bits) causes
DVIDD to ask for the name of an extended command.  The current extended
commands are:

XSPOOL/<printer>
	Runs a DVI spooling program (on a PTY subjob) to send the current
	file to the named printer.  For example, XSPOOL/DOVER sends the file
	to the Dover on the 2nd floor of MJH.  The set of known printer
	names is gotten from tables in the operating system, and you can
	abbreviate the name of a printer as long as it is unambiguous.

	If you give the <meta> (or <control><meta>) prefix to the XSPOOL
	command, then the command line is loaded into your line editor for
	editing before being sent to a PTY to be executed.  This can be used
	to set switches in the command line.

Further details.

The DVI file may contain graphics commands produced by \special control
sequences in TeX.  For the format of these commands, see DVIDOV.IAZ[UP,DOC].
All of the textured rectangle commands (including those not accepted by
DVIdover) are allowed.  The "pen size" parameter in \special{join} commands
is limited only by the DataDisc resolution; there is nothing special about
the 8 values mentioned in DVIDOV.IAZ.

If your document uses a magnification other than 1.44, the program will show
it at magnification 1.44 anyway, unless you use the "/M" switch (see above).
If this causes the pages to be too wide for the screen, use the ← and →
commands to move around and see everything.

If a font requested in the DVI file does not exist, the program will search
for a TFM file instead.  If this is found, then the characters will be shown
as gray rectangles whose dimensions reflect the information in the TFM file.
The default is to outline the rectangles with boxes, but the /-B switch
suppresses the boxes and the /-G switch suppresses the gray interiors.  The
characters will not appear at all if both switches are given.

If for any font, there is neither a GF file, nor a PXL file nor a TFM file,
then DVIDD will not proceed.

Certain fonts are "preloaded", which means that the program already has all
the information in the GF files for those fonts.  If the preloaded fonts get
out of date, DVIDD usually detects the problem by comparing checksums; in
this case, the font file is reread and an "!" is printed.  If for some
reason you want to disable the use of preloaded fonts, put the /-F switch
after the name of the DVI file.  (If you are using such a high magnification
that DVIDD runs out of memory, the /-F switch might help.)