Hewlett-Packard HP-GL Plotters
DESCRIPTION:
Sets the graphics device to be a Hewlett-Packard pen plotter.
USAGE: 
hpgl(width=10, height=7.25, ask=!auto, auto=F,
     color=2, speed=400, rotated=F, file="", hw.control=T)
OPTIONAL ARGUMENTS:
width:
width of the plotted surface in inches.
height:
height of the plotted surface in inches.
ask:
should user be prompted by "GO?" prior to advancing to a new frame?
auto:
logical, can device automatically advance the paper (H-P 7550)?
color:
integer reflecting the degree of color-plotting support provided by the device. 0 means that color changes are ignored, 1 means to prompt the user when color changes (to allow manual pen changes, etc), 2 means that the device has automatic color changing capability.
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.
rotated:
logical, tells whether the long dimension of 8.5 by 11 inch paper is oriented horizontally (not rotated) or vertically (rotated).
file:
file name for capturing HP-GL commands. Ordinarily, the HPGL characters are sent to the user's terminal.
hw.control:
logical, tells whether the hardware control escape sequences are to be included. These escape sequences may be unnecessary depending on how the output is being used. For example, it may help to set hw.control to FALSE when the output will be imported into another software package.
SIDE EFFECTS:
sets the graphics device to an HP pen plotter.
DETAILS:
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.

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.

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.

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.

NOTE:
Always be sure that the pen is capped when you are done with the plotter. 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.
WARNING:
Do not allow two different instances of a graphics device write to the same file. The file will become corrupted if this happens.
SEE ALSO:
Devices , dev.cur , graphics.off .