AIPS HELP file for TVCPS in 31DEC24
As of Thu Apr 25 2:49:34 2024
TVCPS: Task to copy a TV image to a PostScript file.
INPUTS
OUTFILE
Name of the output file.
blank -> place in printer
queue.
COPIES 0.0 50.0 Number of copies if going
directly to a printer
APARM Miscellaneous controls
Paper size:
(1) width
(2) height
(3) margin
(4) units: 0 = in, 1 = cm
2 = pt
Gamma correction (see help)
(5) red channel gamma
(6) green channel gamma
(7) blue channel gamma
Labeling
(9) > 0 -> use portrait
shape always
(10) > 0 -> Use CMYK color
rather than RGB.
OPCODE 'COL ' or ' ' - produce
color output
'GREY' or 'GRAY' or 'B/W ' -
produce grey-scale output
'COLB' - color with blanked
pixels white (DOINV <= 0)
ASPMM Scaling factor (arcsec/mm)
(<= 0) => fill page.
DOINVERS -1.0 1.0 > 0 invert grey scales
DOTV -2.0 1.0 = -2 to read image from disk
TBLC 0.0 4096.0 Bottom Left Corner of image
0=>entire image
TTRC 0.0 4096.0 Top Right Corner of image
0=>entire image
TXINC -100.0 256.0 Load every TXINC'th column
TYINC -100.0 256.0 Load every TYINC'th row
REASON String added at bottom
HELP SECTION
TVCPS
Type: task.
Use: TVCPS reads the current contents of an AIPS TV screen and creates
a PostScript file that will produce a hard copy of the image on
the TV screen. Only visible grey-scale and graphics channels
will be used.
Adverbs:
OUTFILE....The name of the PostScript file. If this is left blank
then the it is automatically placed in the current AIPS
printer queue. If a name is provided, the PostScript image
file will be saved under this name and will not be placed
in the printer queue.
COPIES.....Number of copies to print (0 => 1). Set to 1 when OUTFILE
is specified.
APARM......Miscellaneous controls
Page size.
(1) - width. Default = 8.5 in.
(2) - height. Default = 11 in.
(3) - minimum margin to leave on each side. Default 0.5 in
(4) - units for width and height.
0 - inches
1 - cm
2 - points
(5,6,7) Gamma correction to use (red,green,blue)
< 0 => remove the TV gamma correction, but add none.
>= 0 & < 0.1 => use TV gamma correction in the color
PostScript
>= 0.1 & < 10 => remove TV gamma correction and apply
APARM(5) to red, APARM(6) to green, and APARM(7) to
blue instead. If APARM(6) and/or APARM(7) are zero,
APARM(5) is used for them.
The color values (0 <= v <= 1) are adjusted by
v' = v ** (1/gamma). This is done to the graphics as
well as the black-and-white or color grey-scales.
(8) Not currently used.
(9) TVCPS will use landscape mode (x-axis along height)
whenever that produces a better fit to the paper. To
force it to use portrait mode at all times, set
APARM(9) to a positive number.
(10) > 0 => write the PostScript in the CMYK (cyan,
magenta, yellow, black) color scheme used by
printers. Journals prefer this despite the fact that
it makes the PostScript files 1/3 bigger. <= 0 => use
the traditional RGB (red, green, blue) color scheme.
TVCPS will convert the RGB of the TV to CMYK using
the simple formulae (C=1-R, M=1-G, Y=1-B, K=0 except
for nearly pure blacks). Note that the two color
schemes are not identical. The default gamma
corrections (APARM(5)-APARM(7) = 2.2 = XAS default
gamma value) are often okay for RGB print outs, but
values much closer to 1.0 seem better for CMYK print
outs. If using, CMYK, be sure to experiment and test
the results by actual printing.
OPCODE.....Color or grey-scale output: 'GREY', 'GRAY' or 'B/W ' ->
grey-scale output, otherwise color. Pure zero pixels
(blanked or edge) are black unless OPCODE = 'COLB' where
they are made white. The latter is transparent on some
color printers. 'COLB' does nothing when DOINV > 0.
ASPMM......If positive, the scale of the output image in arcseconds
per millimeter. If this is negative or zero the image
will be scaled to fit the paper. If ASPMM is positive
and more than one image is displayed on the screen then
you will be asked to select the image to which the
scaling will be applied.
DOINVERS...Normally areas that are dark on the TV screen are shown as
dark on the output PostScript printer. To reverse this,
set DOINVERS > 0. One might wish to do this in some cases,
because printers do not show large areas of black well.
DOTV.......If DOTV < -1, then the TV is used to set the intensity
range, function type, and enhancements, but the image data
are read from disk and the plot size is set by the size of
the image read. If DOTV >= -1 (its normal range of
values), then the TV provides the data and the size of the
visible screen (not the area actually used) sets the plot
size. If DOTV < -1, the graphics planes are ignored.
NOTE: This option only works when the image on the TV was
loaded from the current AIPS session (or at least an AIPS
session with the same disk assignments). If more than
one image is visible (i.e. with TVHUEINT or TV3COLOR),
then each image will be read from disk, but all of the
images must have the same image size and coordinates.
TBLC.......The Bottom Left-hand pixel of the sub-array of the map to
be displayed when DOTV < -1. 0 => 1 in each axis.
TTRC.......The Top Right-hand pixel of the sub-array of the map to be
displayed when DOTV < -1. TTRC(3-7) are ignored and 0 =>
the full image on that axis.
TXINC......Use every TXINC'th column beginning at TBLC when DOTV < -1.
0 => 1
TYINC......Use every TYINC'th row beginning at TBLC when DOTV < -1.
0 => 1
REASON.....User text to add at bottom of plot along with (optionally)
the AOC management user number string.
EXPLAIN SECTION
TVCPS: Task which copies the contents of an AIPS TV screen to a
PostScript file.
DOCUMENTER: Chris Flatters, NRAO
PURPOSE
TVCPS is used to make a hard copy of the contents of an AIPS TV display.
The contents of all enabled grey-scale planes and all graphics planes
specified in GRCHAN are read from the TV device and written to a
PostScript file. This file is either placed in the current AIPS printer
queue or saved under a name specified by the user. The file is always
encapsulated.
LIMITATIONS
TVCPS will not provide a perfect reproduction of the TV display.
1) AIPS TV images are gamma corrected (gamma correction takes account of
the fact that color intensity is not linearly related to the voltage
fed to each of the color guns). Gamma correction is applied to the
output image by APARM(5), APARM(6), and APARM(7). The higher the
gamma correction the brighter are the low levels.
2) Grey-scale images use the image intensities from the red channel and
assume that overlay planes 1 to NGRAPH-1 are pure white and overlay
plane NGRAPH (now 8 with XAS) is black.
HINT: Do not make black and white hard-copy of pseudocolour images.
3) Further hints: turn off the grey channels you do not want. Channels
which are merely cleared are read and computed upon, even if they are
all zero. Select only those graphics channels you want with GRCHAN.
All selected graphics channels are read and computed even if they are
all zero or if they are not currently visible.
TVCPS does honor zoom and scroll, giving as faithful a representation of
what you see on the TV screen as possible.
NOTES ON THE POSTSCRIPT OUTPUT
Color images from TVCPS can only be handled by Level 1 PostScript
interpreters that support the CMYK operators or by Level 2 PostScript
interpreters. In general this includes color printers and film
recorders but not some ordinary laser printers. Don't try sending a
color image to any device unless you are sure that it can handle it.
AIPS will detect the presence of color in your file and send it to a
color printer if there is one defined for your site (if INFILE was not
specified).
Grey-scale images can be handled by any PostScript interpreter.
Encapsulated PostScript files contain information that allows images
defined in them to be included in other documents.
TVCPS output conforms to version 3.0 of the Document Structuring
Conventions including version 3.0 of the Encapsulated PostScript File
Format.
REFERENCES
PostScript Language Reference Manual, Second Edition
Adobe Systems Incorporated
Addison-Wesley, 1990
ISBN 0-201-18127-4
STUFF TO KEEP LAWYERS HAPPY
PostScript is a registered trademark of Adobe Systems Incorporated.