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The behavior of tek2plot
is affected by several environment
variables, which are the same as those that affect graph
and
plot
. For convenience, we list them here.
We have already mentioned the environment variables BITMAPSIZE
,
PAGESIZE
, BG_COLOR
, EMULATE_COLOR
,
MAX_LINE_LENGTH
, and ROTATION
. They serve as backups for
the several options ‘--bitmap-size’, ‘--page-size’,
‘--bg-color’, ‘--emulate-color’, ‘--max-line-length’, and
‘--rotation’. The remaining environment variables are specific to
individual output formats.
tek2plot -T X
, which pops up a window on an X Window
System display and draws graphics in it, checks the DISPLAY
environment variable. The value of this variable determines the display
on which the window will be popped up.
tek2plot -T png
and tek2plot -T gif
, which produce output
in PNG format and pseudo-GIF format respectively, are affected by two
environment variables. If the value of the INTERLACE
variable is
"yes", the output file will be interlaced. Also, if the value of the
TRANSPARENT_COLOR
environment variable is the name of a color
that appears in the output file, that color will be treated as
transparent by most applications. For information on what color names
are recognized, see Color Names.
tek2plot -T pnm
, which produces output in Portable Anymap
(PBM/PGM/PPM) format, is affected by the PNM_PORTABLE
environment
variable. If its value is "yes", the output file will be in the
portable (human readable) version of PBM, PGM, or PPM format, rather
than the default (binary) version.
tek2plot -T cgm
, which produces CGM files that comply with the
WebCGM profile for Web-based vector graphics, is affected by two
environment variables. By default, a version 3 CGM file is
generated. Many older CGM interpreters and viewers, such as the ones
built into Microsoft Office and other commercial software, only support
version 1 CGM files. The CGM_MAX_VERSION
environment
variable may be set to "1", "2", "3", or "4" (the default) to
specify a maximum value for the version number. The CGM_ENCODING
variable may also be set, to specify the type of encoding used in the
CGM file. Supported values are "clear_text" (i.e., human readable) and
"binary" (the default). The WebCGM profile requires that the binary
encoding be used.
tek2plot -T pcl
, which produces PCL 5 output for
Hewlett–Packard printers, is affected by the environment variable
PCL_ASSIGN_COLORS
. It should be set to "yes" when producing
PCL 5 output for a color printer or other color device. This will
ensure accurate color reproduction by giving the output device complete
freedom in assigning colors, internally, to its “logical pens”. If it
is "no" then the device will use a fixed set of colored pens, and will
emulate other colors by shading. The default is "no" because monochrome
PCL 5 devices, which are more common than colored ones, must use
shading to emulate color.
tek2plot -T hpgl
, which produces Hewlett–Packard Graphics
Language output, is also affected by several environment variables. The
most important is HPGL_VERSION
, which may be set to "1", "1.5",
or "2" (the default). "1" means that the output should be
generic HP-GL, "1.5" means that the output should be suitable for
the HP7550A graphics plotter and the HP758x, HP7595A and HP7596A
drafting plotters (HP-GL with some HP-GL/2 extensions), and "2" means that the output should be modern HP-GL/2. If the version is
"1" or "1.5" then the only available fonts will be vector fonts, and
all lines will be drawn with a default thickness (the ‘-W’ option
will not work).
The position of the tek2plot -T hpgl
graphics display on the page
can be rotated 90 degrees counterclockwise by setting the
HPGL_ROTATE
environment variable to "yes". This is not the same
as the rotation obtained with the ‘--rotation’ option, since it
both rotates the graphics display and repositions its lower left corner
toward another corner of the page. Besides "no" and "yes", recognized
values for the HPGL_ROTATE
variable are "0", "90", "180", and "270". "no" and "yes" are equivalent to "0" and "90",
respectively. "180" and "270" are supported only if HPGL_VERSION
is "2" (the default).
The drawing of visible white lines is supported only if
HPGL_VERSION
is "2" and the environment variable
HPGL_OPAQUE_MODE
is "yes" (the default). If the value is
"no" then white lines (if any), which are normally drawn with pen #0, will not be drawn. This feature is to accommodate older HP-GL/2
devices. HP-GL/2 pen plotters, for example, do not support the use
of pen #0 to draw visible white lines. Some older HP-GL/2 devices
may, in fact, malfunction if asked to draw opaque objects.
By default, tek2plot -T hpgl
will draw with a fixed set of
pens. Which pens are present may be specified by setting the
HPGL_PENS
environment variable. If HPGL_VERSION
is "1", the default value of HPGL_PENS
is "1=black"; if
HPGL_VERSION
is "1.5" or "2", the default value of
HPGL_PENS
is
"1=black:2=red:3=green:4=yellow:5=blue:6=magenta:7=cyan". The format
should be self-explanatory. By setting HPGL_PENS
, you may
specify a color for any pen in the range #1...#31. For information
on what color names are recognized, see Color Names. Pen #1
must always be present, though it need not be black. Any pen in
the range #2...#31 may be omitted.
If HPGL_VERSION
is "2" then tek2plot -T hpgl
will also be
affected by the environment variable HPGL_ASSIGN_COLORS
. If the value of this variable is "yes", then tek2plot -T hpgl
will
not be restricted to the palette specified in HPGL_PENS
: it will assign colors to “logical pens” in the range #1...#31, as needed. The default value is "no" because other than color LaserJet
printers and DesignJet plotters, not many HP-GL/2 devices allow the
assignment of colors to logical pens. In particular, HP-GL/2 pen
plotters do not.