.TH PSI 9.1
.CT 1 writing_output
.SH NAME
psi \- postscript interpreter
.SH SYNOPSIS
.B psi
[
.I option ...
] [
.I file
]
.SH DESCRIPTION
.I Psi
reads Postscript input from
.I file
or from standard input
and simulates the resulting pages in a
.IR mux (9.1)
layer.
The program remains in the layer at exit; further invocations of
.I psi
in that layer avoid download time.
.PP
The options are
.TP
.BI -p n
Display page
.IR n ,
where
.I n
is determined from the
.B %%Page
comments in the file.
If these are not present, page selection will not work.
.TP
.B -R
Pages in the file are in reverse order. This flag must be used on such files
for the
.I -p
option to work.
.TP
.B -r
Display the image at full scale, with the bottom left
corner positioned at the bottom left corner of the window.
(By default, the image is scaled to fit the window, maintaining
the aspect ratio of a printer.)
.HP
.B -a
.I x y
.br
Display the image at full scale with position
.I x,y
of the image placed at the bottom left corner of the window.
.PP
.I Psi
works on either a Teletype 5620, 630 or 730 terminal
as determined by the environment variable
.BR TERM .
.PP
Fonts are implemented with size-24 bitmap fonts.
Those available are
Symbol, Courier, Times-Roman, Times-Italic, Times-Bold, Times-BoldItalic, Helvetica,
Helvetica-Oblique, Helvetica-Bold, Helvetica-BoldOblique.
Fonts
Courier-Bold,
Courier-Oblique,
and
Courier-BoldOblique
are mapped to
Courier.
Other postscript fonts, including type1, may be used if
they are supplied before they're referenced.
.PP
When the `cherries' icon is displayed, use mouse button 3
to move forward
.RB ( more ),
to a particular page
.RB ( page ),
or quit 
.RB ( done ).
Button 2 exits the program completely.
.SH EXAMPLES
.TP
.L
troff -ms memo | lp -dstdout -H | psi
.br
.ns
.TP
.L
troff -ms memo | dpost | psi
Two equivalent ways to format a memo, convert it to PostScript,
and display it.
.PP
For best results with TeX documents, use
.B dvips
with the
.BR -Tjerq ,
.BR -Tgnot ,
or
.B "-D 100"
option to get fonts of the proper resolution and run
.I psi
with the
.I -r
or
.I -a
flag to prevent
.I psi
from scaling.
.SH FILES
.TF psi.err
.TP
.F psi.err
error messages
.SH SEE ALSO
.IR lp (1),
.IR dvips (1),
.IR postscript (8),
.IR proof (9.1),
.IR psifile (1),
.IR psix (1)
.SH DIAGNOSTICS
A `dead mouse' icon signals an error;
error comments are placed on file
.FR psi.err .
.PP
Symbols that lack bitmaps are replaced by `?'
and an error is reported.
.SH BUGS
A psi layer imitates
.LR "term 33" ,
not
.IR mux .
Among other difficulties, it will not be reusable if downloaded
across the network.
.br
Unimplemented PostScript features are rotated images and
half tone screens.
Imagemasks may only be rotated by multiples of 90 degrees, not
by arbitrary angles.
.br
Skipping pages may cause operators to be undefined.