ctrans(1NCARG)
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.
FILES
$NCARG_ROOT/lib/ncarg/graphcaps/*
The binary NCAR Graphcap files
$NCARG_ROOT/lib/ncarg/fontcaps/*
The binary NCAR Fontcap files
SEE ALSO
fcaps(1NCARG), fontcap(5NCARG), gcaps(1NCARG), graphcap(5NCARG), idt(1NCARG), ras_palette(5NCARG), med(1NCARG), ictrans(1NCARG) Hardcopy: NCAR Graphics Fundamentals, UNIX Version
CAVEATS
Running in "movie" mode may give surprising results on slower devices, such as dumb terminals. If too short a time interval is specified slow devices may not have finished rendering before the movie timer expires. This results in no pause between frames. Metafiles which reference color table indices that were not previously defined may have varying results from one device to the next. Using the -wid option to have ctrans display its output in a window created by another X application may produce unexpected results, particularly with regard to color. At ctrans' current level of implementation, the subset of CGM elements supported is closely approximated by the list provided in NCAR's Graphics Installer's Guide, Version 2.00 (August 1987). However, the best way to determine whether a particular CGM element is supported by the translator is feed a metafile containing the element in question to ctrans. Consult the aforementioned publication for a discussion of Graphcaps and Fontcaps as well.
COPYRIGHT
Copyright (C) 1987-2009 University Corporation for Atmospheric Research The use of this Software is governed by a License Agreement.
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