PROCESSING(1) COMMAND REFERENCE PROCESSING(1)
NAME
processing - perform corrections and user-selected
alterations to a GRF screen_data file
SYNOPSIS
processing [ -h ] [ -o device ] [ -C local|none ] [ -B
local|none ] [ -G local|none ]
[ -I local|color1=color2|none ] [ -D
[rotate:]matrix_size[:local] ] [ -b border_color ]
[ -f forms ] [ -M colormap_file ] [ -d dither_file ] [ -g
gamma_file ]
DESCRIPTION
The processing command does picture image processing on
Generic Raster Format (GRF) files; it takes a GRF
screen_data file, makes it suitable for color printing, and
produces a GRF copy_data file.
The processing command performs both required and optional
functions, including dithering, intensity and color
corrections, and adding picture borders; it adds or modifies
some GRF tags to reflect data changes it makes. Other
options are turned into printer commands by the GRF protocol
drivers (tcprdrv_Tek.4692(8mdqs), tcprdrv_Tek4693D(8mdqs),
and tcprdrv_Tek.4696(8mdqs)) that send output to a color
printer.
The functions of this program are largely under user
control. Vital file information such as the scan size,
color map, color units and field widths are obtained from
the GRF header, normally written by the screencopy command
(see screencopy(1)). Optional and user-alterable parameters
are specified on the command line.
The GRF screen_data input file is read from standard input.
The GRF copy_data output file is written to standard output.
The processing command acts as a filter by reading in the
GRF header from the image file and adding or changing GRF
tags based on user-supplied command line arguments. The
resulting set of GRF tags are interpreted to process the
image file. GRF tags that result in processing are deleted
from the header when the image file is written out. GRF tag
parameter values not recognized by the processing command
are not interpreted and passed on in the header. For more
information on GRF headers and tags, see grf(5).
The following set of GRF tags and parameters process the
image file:
color_correction {local}
Performs built-in color correction. A color_correction
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PROCESSING(1) COMMAND REFERENCE PROCESSING(1)
tag value other than local passes on in the GRF header of
the copy_data output file for interpretation by a GRF
protocol driver. Color correction matches the screen
colors to the ink colors of the printer.
black_correction {local}
Performs built-in black correction. A black_correction
tag value other than local is passed on in the GRF header
of the copy_data output file for interpretation by a GRF
protocol driver. Black correction matches gray levels of
the screen to the grays of the printer.
gamma_correction {local|[d,256]|[d,3,256]}
Performs built-in gamma correction using a table of 256
gamma intensity values. A gamma_correction tag value of
local uses a table of default gamma intensity values
found in the default file /usr/lib/tcpr/tcprgamma or
specified by the -g command line option. A table of
gamma intensity values can also be included by a GRF tag
gamma_correction [d,256] followed by a 256 entry table of
gamma intensity values or a gamma_correction [d,3,256]
followed by three 256 entry tables, one for each primary.
Any other tag value for gamma_correction is passed on in
the GRF header of the copy_data output file. Gamma
correction matches the intensity of the screen to the
color printer.
dithering_matrix {[rotate90_]local_nxn|[rotate90][d,n,n]}
Performs built-in ordered dithering using the specified
matrix of size n. The dither matrix size n can be 2, 4,
8, or 16 which corresponds to a 2 by 2, 4 by 4, 8 by 8,
or 16 by 16 square matrix used in the dithering process.
The various matrix sizes allow for the tradeoff between
the truer colors obtained with a larger dither size and
the finer detail of a smaller dither size for an image.
The dither_matrix tag value local reads a matrix of size
n read from the default file /usr/lib/tcpr/tcprdither. A
dither matrix can also be included by using the GRF tag
dither_matrix [d,n,n]. Dither patterns can be rotated 90
degrees by prepending the GRF tag value with rotate90.
An alternate file of dithering matrices can be specified
by the -d command line option.
invert_bw {local|color1=color2}
Performs built-in inversion of any two color pixels.
The tag value local inverts black and white pixels. Text
is best reproduced on paper as black letters on a white
background, whereas it is frequently displayed on
terminal screens as white letters on a black background.
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PROCESSING(1) COMMAND REFERENCE PROCESSING(1)
Black and white pixel inversion prints white letters
displayed on the terminal screen as black letters on the
color printer.
Color values are swapped using the color1=color2 tag
value. The processing command recognizes, at a minimum,
the colors red, green, blue, cyan, magenta, yellow, white
and black. Additional colors can be defined in the header
of the image file.
An invert_bw tag value other than the two described is
passed on in the GRF header of the copy_data output file.
border_color {red|green|blue|cyan|magenta|yellow|
white|black|none}
Places a border of a specific color, or no border, around
the color image. The border_color GRF tag is interpreted
by the processing command only and has no meaning to the
GRF protocol drivers.
A white border places white pixels around the image,
making the edges white if on paper and clear if on a
transparency.
Other border color values create a border by filling all
unused image border with the specified color value. A
black border is best when making transparencies for an
overhead projector.
The default is none. It specifies no border. This is the
same as specifying white, except the image border is not
filled in.
OPTIONS
-h Generates a help message containing additional
information on the processing command line options and
their parameter values.
-o device
Overrides the destination_device GRF tag in the GRF
header of the screen_data image file. This tag specifies
the type of output device-dependent processing performed
on the GRF image file. Valid output devices are the
following Tektronix color printers: 4693d, 4692, and
4696.
-C local|none
Enables (local) or disables (none) the local built-in
color correction function. This overrides the GRF tag
color_correction found in the GRF header of the
screen_data input file. If this option is not used the
default is specified by the color_correction GRF tag
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PROCESSING(1) COMMAND REFERENCE PROCESSING(1)
entry in the input file. If no color_correction tag is
found the default is none.
-B local|none
Enables (local) or disables (none) the local built-in
black correction function. This overrides the GRF tag
black_correction in the GRF header of the screen_data
input file. If this option is not used the default is
specified by the black_correction GRF tag entry in the
input file. If no black_correction tag is found the
default is none.
-G local|none
Enables (local) or disables (none) the local built-in
gamma correction function. This overrides the GRF tag
gamma_correction found in the GRF header of the
screen_data input file. If this option is not used the
default is specified by the gamma_correction GRF tag
entry in the input file. If no gamma_correction tag is
found it defaults to none.
-I local|color1=color2|none
Enables or disables color pixel inversion, excluding the
image border. This overrides the GRF tag invert_bw in the
GRF header of the screen_data input file.
The local option enables black and white pixel inversion.
The color1=color2 option enables color pixel inversion.
Valid colors are red, green, blue, cyan, magenta, yellow,
white, and black.
If this option is not used the default is specified by
the invert_bw GRF tag entry in the input file. If no
invert_bw tag is found it defaults to none.
-D [rotate:]matrix_size[:local]
Specifies the size of the n by n matrix to use in the
local ordered dithering. This overrides the GRF tag
dithering_matrix found in the GRF header of the
screen_data input file. The dither matrix_size parameter
can be 2, 4, 8, or 16 which corresponds to a 2 by 2, 4 by
4, 8 by 8, or 16 by 16 matrix. A dither matrix_size of 0
disables all dithering. If this option is not used the
default is specified by the dithering_matrix GRF tag
entry in the input file. If no dithering_matrix tag is
found it defaults to no dithering.
-b border_color
Specifies the border color, or no border, to place around
the image. Overrides the GRF tag border_color found in
the GRF header of the screen_data input file;
border_color values are red, green, blue, cyan, magenta,
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PROCESSING(1) COMMAND REFERENCE PROCESSING(1)
yellow, white, black, or none.
If this option is not used the default is specified by
the border_color GRF tag entry in the input file. If no
border_color tag is found it defaults to none.
-f forms
Specifies the media forms for the GRF image file. The
forms type is needed to place the border around the
image. Valid forms must correspond to the printer type
the image is processed for and is found in the tcprforms
file (see tcprforms(5)).
-M colormap_file
Specifies an alternate file to read in the color map for
the GRF image; it replaces the existing color map. The
colormap_file must be a GRF file containing the colormap
and color_units GRF tags to describe the color map.
-d dither_file
Specifies an alternate file of ordered dithering
matrices. This file replaces the default file used by
the processing command. The dither_file must be a GRF
file containing a set of dithering_matrix GRF tags to
describe a set of 2 by 2, 4 by 4, 8 by 8, or 16 by 16
ordered matrices.
-g gamma_file
Specifies an alternate file of gamma intensity
correction. This file replaces the default file used by
the processing command. The gamma_file must be a GRF
file containing the GRF tag entry gamma_correction
[d,256] followed by a table of 256 gamma intensity values
or a gamma_correction [d,3,256] tag followed by three 256
entry tables, one for each primary.
EXAMPLES
The following example reads the GRF screen_data file file1
from standard input, processes it based on the GRF tags
found in the input stream, and writes the processed GRF
copy_data file to file2 using standard output.
processing <file1 >file2
The following example does local color and gamma correction
on the GRF screen_data input file file1 and places a black
border around the image; the resulting copy_data output file
is spooled to the color printer using the tcpr command.
These options override the GRF tags found in the input file.
processing -C local -G local -b black <file1 | tcpr
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PROCESSING(1) COMMAND REFERENCE PROCESSING(1)
The following example processes the screen_data input file
file1 with a 16 by 16 ordered dithering matrix read from the
file /usr/johns/ditherfile, instead of from the default
file, /usr/lib/tcpr/tcprdither.
processing -D 16 -d /usr/johns/ditherfile <file1 >file2
FILES
/usr/lib/tcpr/tcprdither
Contains the processing command's default
set of ordered dithering matrices. The
file contains entries for 16 by 16, 8 by 8,
4 by 4, and 2 by 2 ordered matrices. The
matrices in this file give good results on
Tektronix color printers.
/usr/lib/tcpr/tcprgamma
Contains the processing command's default
gamma intensity correction values. The
gamma intensity values in this file give
good results when doing gamma correction
for Tektronix 410X series color terminals.
/usr/lib/tcpr/tcprforms
Contains the valid set of tcpr media forms
for all valid Tektronix color printers.
stdin Image input is a GRF screen_data file.
stdout Image output is a GRF copy_data file.
RETURN VALUE
[NO_ERRS] Command completed without error.
[USAGE] Incorrect command line syntax. Execution
terminated.
[NP_WARN] An error warranting a warning message
occurred. Execution continues.
[NP_ERR] An error occurred that was not a system
error. Execution terminated.
[P_WARN] A system error occurred. Execution continues.
See intro(2) for more information on system
errors.
[P_ERR] A system error occurred. Execution
terminated. See intro(2) for more
information on system errors.
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PROCESSING(1) COMMAND REFERENCE PROCESSING(1)
DIAGNOSTICS
The processing command can issue more than 50 different
error messages, mostly for bad parameter syntax and
erroneous input values.
SEE ALSO
grf_compress(1), grf_expand(1), screencopy(1), st_grf(1),
x_grf(1), tcpr(1mdqs), tchc(4), grf(5), tcprdither(5),
tcprforms(5), tcprgamma(5), mdqsd(8mdqs),
tcprdrv_Tek4692(8mdqs), tcprdrv_Tek4693D(8mdqs),
tcprdrv_Tek4696(8mdqs), and tcprserver(8mdqs).
REFERENCES
For more information, consult the Users Manual for your
system.
Printed 4/6/89 7
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