ctransNCARG - Online in the Cloud

PROGRAM:

NAME

ctrans - a Computer Graphics Metafile ( CGM ) translator

SYNOPSIS

ctrans [ -bell ] [ -d device ] [ -f font ] [ -lmin min ] [ -lmax max ] [ -lscale scale ] [
-movie time ] [ -outfile file ] [ -pal pal_fname ] [ -pause ] [ -quiet ] [ -record
record_num ... ] [ -soft ] [ -verbose ] [ -Version ] [ -viewport llx:lly:urx:ury ] [ -wid
window_id ] [ -window llx:lly:urx:ury ] [ device-specific options ] [ - | metafile ... ]

DESCRIPTION

ctrans is a metafile translator, taking metafile(s), a metafile stored in the NCAR
Computer Graphics Metafile (CGM) standard, and interpreting its instructions on the device
defined by the GRAPHCAP environment variable. Fonts are stroked according to
specifications in the Fontcap file defined by the FONTCAP environment variable. ctrans
utilizes Graphcaps by default, see graphcap(5NCARG), while providing optional processing
by user provided libraries, if that is required by the device or desired by the user.
Thus, ctrans is capable of driving any device for which a Graphcap is available; with
programming modifications, ctrans can accommodate any device for which an external library
of plotting routines is available. Currently, the following Graphcap independent devices
are supported: X11 under release 4 and 5, version 11 of X.

ctrans can also translate metacode into the following raster formats: a60, avs, hdf,
hppcl, nrif, sun and xwd. The device specifier for these raster formats is the name of
the format. For example "-d xwd" specifies translation to an xwd formatted raster file.
Additionally, a clear text driver, "-d CTXT", is available on any terminal. Not all of
the aforementioned devices may be supported by your particular configuration of ctrans.
For a list of supported devices see the gcaps(1NCARG) command.

ctrans will read from the standard input if no metafile name is specified or the the name
specified is `-'.

OPTIONS

-bell Ring the bell at the end of each frame. The default is to run in silent mode. This
option is not supported by all devices.

-d device
Device name. ctrans will use the Graphcap (if it exists) or the appropriate
graphics library indicated by device;

If device is preceded by a UNIX directory path then ctrans will look in that
directory for the specified graphcap. Otherwise ctrans searches the directory
$NCARG_ROOT/lib/ncarg/graphcaps for the graphcap.

For all device specifications except X11 output is directed to standard out. In the
case of X11 translation results in appropriate calls to the X11 libraries. See
graphcap(5NCARG) for a description of supported devices. See gcaps(1NCARG) for a
list of devices supported by your particular configuration of ctrans.

This option overrides the GRAPHCAP environment variable.

-f fontcap
Fontcap file to be used for stroking text. When interpreting CGM TEXT command
elements use fontcap as the default font for textual translation. Note: CGMs may
contain textual descriptions which are not embedded in CGM TEXT elements. Hence
they are not influenced by fontcap specifications. Note also that a CGM may
explicitly specify a named font which may override a font provided on the command
line. The environment variable FONTCAP may also be used to specify a default
fontcap.

If fontcap is preceded by a UNIX directory path then ctrans will look in that
directory for the specified fontcap. Otherwise ctrans searches the directory
$NCARG_ROOT/lib/ncarg/fontcaps for the fontcap.

See fontcap(5NCARG) for a description of the available fontcaps. See fcap(1NCARG)
for a list of the fontcaps installed on your system.

This option overrides the FONTCAP environment variable.

-lmin min
On devices which support line width scaling all lines are guaranteed to be scaled
at least min times the default line width for that device. This option effectively
insures that the minimum value for the CGM element "LINE WIDTH" is min.

-lmax max
On devices which support line width scaling all lines are guaranteed to be scaled
at most max times the default line width for that device. This option effectively
insures that the maximum value for the CGM element "LINE WIDTH" is max. The
results of setting max less then min are undefined.

-lscale scale
On devices which support line width scaling all line width specifications within
the metafile will be scaled by scale. This option is subject to modification by
the -lmin and -lmax options.

-movie time
Set pause to time seconds. In normal operation mode the translator requires user
interaction after the display of each plot. ctrans will not proceed until the user
responds. If movie mode is set ctrans will wait time seconds after the display of
each frame and then proceed automatically. This option and the -pause option are
mutually exclusive.

This option may not behave as expected on slower devices.

-outfile file
Direct translator output to file. By default translator output is written to the
standard output. This option has no effect for devices of which ctrans has a
function-callable interface. e.g. X11 .

-pal pal_fname
Use the color palette defined in the file pal_fname for subsequent translation of
the metafile. This palette will override any color map defined by the CGM being
translated. For a description of the format of pal_fname see ras_palette(5NCARG).

-pause Pause after each frame in the metafile is displayed and wait for the user to type a
newline before proceding. This option is probably only useful when used in
conjunction with the -wid option as this is the normal behaviour for ctrans in most
instances. This option and the -movie option are mutually exclusive.

-quiet Suppress reporting of non-fatal (warning) error messages; only fatal error messages
are reported.

-record
< record_number... >
If processing only single frames of the metafile is desired, this option specifies
the record number containing the start of that frame. ctrans assumes the
processing is to start at the first BEGIN PICTURE element in that record. The user
must perform bookkeeping to determine the record that contains the desired frame.
Normally, a metafile editor (e.g., ictrans(1NCARG). may be used as the actual user
interface to perform this bookkeeping. Without a specified record number, ctrans
processes the entire metafile.

-soft Unconditionally perform software filling of all filled polygons. This option may be
useful for devices which do not support the filled polygon drawing primitive or
have limits on the number of vertices describing a polygon. On some devices this
number is known and software filling is performed, as appropriate, without user
specification.

-verbose
Operate in verbose mode.

-Version
Print the version number and then exit.

-viewport llx:lly:urx:ury
Set the viewport of the output device. The viewport is the rectangular region of
the output device of which the virtual device coordinate system of the metafile is
mapped onto. Normally this region is the largest device-addressable square which
fits in the center of the device address space. The -viewport option may be used to
change the default mapping. llx and lly specify the lower left corner of the
device in normalized coordinates. urx and ury specify the upper right corner of
the device in normalized coordinates. For example, -viewport 0.0 0.0 0.5 0.5,
specifies the lower left corner of the device.

-window llx:lly:urx:ury
Specify the workstation window (in the GKS sense). Four coordinates are specified
which define a rectangular window which is a subset of the normalized VDC rectangle
with corner points (0,0) and (1.0,1.0). llx and lly specify the lower left corner.
urx and .ury specify the upper right corner. The specified window is mapped onto
the entire display viewport. For example, if the workstation window is defined by
the corner points (0,0) and (0.5 0.5) then the lower left quarter of a plot would
be blown up to fill the entire viewport. Specification of such a window can be
used for zooming and panning.

The range with which one may zoom in on a plot may be limited by the integer
addressing precision of the device.

DEVICE-SPECIFIC OPTIONS:

The following options are available when the device is graphcap-driven (See the
gcaps(1NCARG) command for a list of graphcap-driven devices):

-simulatebg
Simulate CGM background color requests by drawing a large filled rectangle of the
appropriate color. This option is useful for devices such as color PostScript
printers which have no concept of background color.

The following options are available when device is CTXT:

-Data Suppress display of CGM output primitive data. All other CGM element data is
displayed. This may substantially reduce the verbosity of the clear text driver.

-Para Suppress display of CGM element data except for output primitives. The -Data
combined with the -Para option permit the display of only the CGM element names.

The following options are available when device is X11:

-background color
Specifies the default window background color for color devices. If the metafile
explicitly sets color index 0 then this option is overridden.

-foreground color
Specifies the default foreground color for color devices. If the metafile
explicitly sets color index 1 then this option is overridden.

-geometry geometry
Specify the size and/or position of the graphics window in the format of an X11
Window System geometry string.

-ignorebg
Ignore requests to change the background color. This option may be useful when
ctrans renders into a X window created by an application other than ctrans. As a
side effect of this option the rendering window is not cleared between frames.

-reverse
On monochrome devices reverse video is simulated by swapping the foreground and
background colors.

-wid window_id
Render into the previously created X window specified by window_id. Normally
ctrans creates its own window for plotting. The window specified by window_id must
be of type InputOutput. The window must also have inherited its color map, depth
and visual class from the root window.

Note also that when this option is used ctrans cannot receive X events from the
drawing window. Hence, ctrans cannot use "mouse clicks" as a signal to advance
frames. For this reason the -pause option is useful to prevent ctrans from
processing the entire metafile without pausing between frames.

window_id may be specified as a decimal or hexidecimal integer.

The following options apply to the X11 color map management of ctrans when device is X11:

ctrans supports three different methods of X11 color map management.

If the user specifies a shared color map (using the -scmap option), then ctrans
will use the default X color map for the screen, that is shared by all
applications. If the metafile contains more colors than there are available in the
default X color map, then a color matching algorithm is employed. The idea of the
algorithm is that the color in the current color table that is closest to the
requested color will be selected. Closest is defined in terms of the normal
distance metric on the RGB cube. If the closest color is equal to or farther away
than the percentage error allowed ( -colerr ), then a warning message will be
printed. The closest color is still used.

If the user specifies a private color map (using the -pcmap option), then ctrans
will create a private color map for the graphics window. This will guarantee that
256 distinct colors are available to the window. This means that the X window
will have a different color map than all the other windows on the screen.
Therefore, you usually have to have the mouse pointer in the window for the correct
color table to be installed. One disadvantage to this option is that there is
usually a color flashing effect on the screen since the wrong color table will be
installed for the other windows on the screen.

The default color map management scheme attempts to take the best of the two
previous models. It starts out behaving like the shared model, in that it uses the
default color map for the screen. It differs in that, once it can't allocate any
more colors from the default color map, in allocates its own private color table
and starts using it. This way, the color flashing is only present if it absolutely
needs to be so that ctrans can display the correct color.

-scmap Ask ctrans to use the shared default X color map only.

This is the option used if -wid is specified.

-colerr n
Specifies the percentage color error that is acceptable if the -scmap option is
being used. If the color being used is n percentage or more different from the
color requested, a warning will be reported by ctrans.

-pcmap Ask ctrans to create its own X color map and use it exclusively.

This option is ignored if the -wid option is present.

The following options are available when device is a60, avs, hdf, hppcl, nrif, sun, or
xwd:

-dpi dpi
Specify the number of dots per inch. This option is only meaningful for the HP
LaserJet, hppcl, which ignores the -resolution option. dpi may be one of 75, 100,
150, or 300. The default is 150.

-direct
By default ctrans outputs raster imagery with 8-bit-indexed encoding. When this
option is used, if the raster file format supports it, raster imagery is output in
a 24-bit-direct encoding scheme. Be warned: the resultant file is three times the
size of its 8-bit-indexed counterpart.

-landscape
Generate the image in landscape mode. This option is ignored by all raster devices
except the HP LaserJet, hppcl. By default the LaserJet uses portrait mode.

-resolution widthxheight
width and height specify the spatial resolution in pixels of the raster file to be
created. The default is 512x512.

EXAMPLES

To process a metafile named gmeta and display its contents on the TEKTRONIX 4107 terminal,
use the following call:

% ctrans -d t4107 gmeta

If this device is already defined by the GRAPHCAP environment variable, simply call:

% ctrans gmeta

If you wish to display only the first frame starting in the third record, call:

% ctrans -record 3 -d t4107 gmeta

To examine the metafile gmeta's contents without CGM element data being displayed:

% ctrans -d CTXT -Data -Para gmeta

To render the metafile gmeta (under X Windows) in a window that is 512x512 pixels in
dimension in the lower right corner of your screen

% ctrans -d X11 -geometry 512x512-0-0 gmeta

To rasterize the contents of the metafile gmeta at a resolution of 1024x1024 pixels, call:

% ctrans -d xwd -res 1024x1024 > raster.xwd

The raster output is in X11 "xwd" format and is sent to the file raster.xwd.

To zoom in on the upper right quarter of the metafile gmeta and display it in an X window,
call:

% ctrans -d X11 -window 0.5:0.5:1.0:1.0

ENVIRONMENT

FONTCAP
Default fontcap specifier.

GRAPHCAP
Default output device specifier.

NCARG_ROOT
Path to root of NCAR Graphics installation.

NCARG_LIB
If set this variable contains the path to the installed NCAR Graphics libraries.
NCARG_LIB overrides NCARG_ROOT.

NCARG_TMP
If set, this environment variable contains a directory path to be used for
temporary files. On most systems the default is /tmp. On some systems the default
is /usr/tmp.

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