.BG
.FN hpgl
.TL
Hewlett-Packard HP-GL Plotters
.CS
hpgl(width=10, height=7.25, ask=!auto, auto=F,
     color=2, speed=400, rotated=F, file="")
.AG width
width of plotted surface in inches.
.AG height
height of plotted surface in inches.
.AG ask
should user be prompted by "GO?" prior to advancing
to new frame?
.AG auto
logical, can device automatically advance the paper (H-P 7550)?
.AG color
integer reflecting the degree of color-plotting support
provided by the device.  0=color changes ignored, 1=prompt
user when color changes (to allow manual pen changes, etc),
2=device has automatic color changing capability.
.AG speed
maximum allowed axis pen velocity ranging from 1 to 400 mm/sec.
Slower speeds are useful for high-quality work or
for plotting on special paper or film.
.AG rotated
logical, tells whether the long dimension of 8.5 by 11 inch
paper is oriented horizontally (not rotated) or vertically (rotated).
.AG file
file name for capturing HP-GL commands.  Ordinarily, the HPGL
characters are sent to the user's terminal.
.PP
This function works with plotters which accept the Hewlett-Packard HP-GL
instruction set.
This includes H-P pen plotter models 7220, 7470, 7475,
7550, and 7225.
The plotters may be used with standard 8.5 by 11 inch paper with the
long dimension horizontally or vertically, or
with other paper sizes by means of arguments `width' and `height'.
.PP
If `auto' is `FALSE',
then whenever a new plot is about to be produced, the message "GO?" appears
on the terminal.  At this time, new paper may be loaded, pens changed,
etc.  When ready for plotting to proceed, simply hit carriage return.
.PP
When graphic input (`identify', `locator') is requested, the `enter'
button will light.  The pen should be positioned by means of the 4
directional buttons.  When the desired pen position is reached,
depress the `enter' button.  To terminate the input, hit carriage
return on the terminal.  The coordinates of the terminating point are
not transmitted.
.PP
Character sizes may be changed to any desired value.  Color can be
changed to any of the values 1 to 8, indicating the pens in stables 1
to 8.  Characters can be rotated to any orientation.  Different line
styles (1, 2, ...) are available, with patterns becoming more spread-out
as the line style is larger.
.PP
Always be sure that the pen is capped when you are done
with the plotter.
.SH NOTE
The switches on the back of the device should be set to reflect
the correct speed and parity settings for the computer system.
Incorrect parity settings may cause failures of digitizing functions, e.g.,
`locator' and `identify'.
.PP
A device must be specified before any graphics functions can be used.
.KW device
.WR
