AIPS HELP file for POSTSCRIPT in 31DEC24
As of Fri Apr 19 8:16:36 2024
HELP SECTION
POSTSCRIPT
Type: information
Use: AIPS converts printed and plotted output into PostScript files.
These are straightforward text files which can be modified with
an editor prior to printing or inclusion in some other document
(e.g. LaTeX papers). The explain section of this help file
describes the macros used by AIPS tasks to display plot data.
It also includes some macros that you could invoke inside your
plot file to add annotation such as arrows to point to and label
image features ("component A, B, C...") or to provide an
additional scale ("1 pc").
Tasks:
LWPLA.....Convert a plot file to PostScript with coloring options.
TVCPS.....Convert the current TV display to PostScript.
TVRGB.....Make TV image and output PostScript from true color (RGB)
images or from 3 images taken as RGB.
EXPLAIN SECTION
POSTSCRIPT: Information about AIPS' usage of PostScript
AIPS deliberately tries to keep its output PostScript files as simple
as possible. This allows the user to modify them without too much
difficulty. Note that PostScript is a programming language very
similar to FORTH and that PostScript files are simple text files which
may be edited by your favorite editor (emacs, vi, et al.). Some
graphics programs can read in PostScript, modify the picture, and then
write the result back out as PostScript (usually with much more
complicated forms).
PostScript is a full language and we cannot describe it in detail
here. References are given below. Critical things to know:
1. Comments are text following a percent sign in the line
2. Graphics commands
x y moveto moves attention to (x,y)
x y lineto draws line to (x,y)
x y r a1 a2 arc draws arc of radius r about (x,y) from angle
a1 to angle a2
3. Text written
/TextFont /Courier-Bold findfont 22 scalefont def
TextFont setfont
(TAN) show
Where the first line defines a symbol as a particular font
the second line sets the font to that symbol and the third line
draws a string ("TAN") in that font starting at the current
position.
4. Global things to do
You can rotate, shift, and scale the whole plot by the addition
of commands near the top:
Fx Fy scale
Dx Dy translate
a rotate
The "translate" will be illustrated in the example describing how
to handle outputs of HUINT at the end of this file.
5. Encapsulated PostScript requires the first line to declare the file
to be PostScript and EPSF and somewhere there must be a bounding box
command giving the plot coordinate range (in points):
percent!PS-Adobe-2.0 EPSF-2.0
percent percentBoundingBox: llx lly urx ury
Note that these are both "comments". Ghostview is useful in
determining the correct bounding box. Modern LWPLA outputs put the
BoundingBox information at the end by putting this line near the
start
percent percentBoundingBox:(atend)
and then the actual BoundingBox at the end
percent percentTrailer
percent percentPages: 1
percent percentBoundingBox: 36 178 576 613
userdict /end-hook known {end-hook} if
percent percentEOF
Text taken from a 2004 LWPLA output as a start of an AIPS PS file
(with added comments)
percent!PS-Adobe-3.0 EPSF-3.0
percent percentBoundingBox: 0 0 988 778
percent ....
percent etc
percent
percent percentEndComments
percent percentBeginProcSet: lwpla.pro
percent define symbols
percent 2 arguments moves current point
/m {moveto} def
percent 2 arguments actually draws line
percent (with stroke) starts new section
/v {lineto currentpoint stroke moveto} def
percent offsets and draws a character string
/c {rmoveto gsave currentpoint translate rotate
show grestore} def
percent Grey scale
/g {save hafpix hafpiy rmoveto currentpoint
translate pscalx pscaly scale
npix 1 8 [npix 0 0 1 0 0] {currentfile npix string
readhexstring pop} image restore} def
percent RGB scale
/G {save hafpix hafpiy rmoveto currentpoint
translate pscalx pscaly scale
npix 1 8 [npix 0 0 1 0 0] {currentfile 3 npix mul string
readhexstring pop} false 3 colorimage restore} def
percent CMYK scale
/H {save hafpix hafpiy rmoveto currentpoint
translate pscalx pscaly scale
npix 1 8 [npix 0 0 1 0 0] {currentfile 4 npix mul string
readhexstring pop} false 4 colorimage restore} def
percent percentEndProcSet
percent Dots BoundingBox
percent (1/300 inch) (1/72 inch)
percent percentEndProlog
percent usual start up stuff
userdict /start-hook known {start-hook} if
percent percentPage: 1 1
percent percentExtensions: CMYK
percent percentRequirements: color
userdict /bop-hook known {bop-hook} if
/vmsave save def
percent draws a box around the full area
percent and fills it with a background
percent color - black
percent these were edited to correct for
percent the hand shifting and scaling
0 0 moveto 988 0 lineto 988 778 lineto 0 778 lineto
0 0 lineto fill stroke
percent scales to make larger for
percent conversion to jpg
percent these were added by hand
1.54 1.54 scale
-76 -54 translate
percent PostScript plots in "points"
percent 72 per inch. rescale so that
percent all AIPS plots are in dots for a
percent 300 dots/inch printer
72 300 div dup scale
percent sample rotation commented out
percent percent 2550 0 translate 90 rotate
1 setlinejoin 1 setlinecap
3 setlinewidth
/Helvetica-Bold findfont 54 scalefont setfont
newpath gsave
percent following vectors are of type labeling
0.850 0.850 0.900 setrgbcolor
681 2244 m
percent the arguments to c are
percent (str) rotate Dx Dy
(CENTAUR IPOL 4635.100 MHZ CENTAU-C1BC.ICLN.1) 0 0 21 c
percent thus
681 1386 m
(Declination \(J2000\)) 90 -297 -257 c
percent standard ending
stroke
vmsave restore
showpage
userdict /eop-hook known {eop-hook} if
percent percentTrailer
percent percentPages: 1
userdict /end-hook known {end-hook} if
percent percentEOF
percent sample of color image
percent one row of step wedge (mostly red)
609 1836 m
/hafpix -5 def
/hafpiy -5 def
/pscalx 2492 def
/pscaly 10 def
/npix 250 def
G
0000000525E30091C000D27900EF2A27FF008FFF00F7FF00FFFF00FFF600FFCE00FFAA00
FF8100FF6100FF3C00FF1C00FF0000FF0000FF0000FF0000FF0000FF0000FF0000FF0000
FF0000FF0000FF0000FF0000FF0000FF0000FF0000FF0000FF0000FF0000FF0000FF0000
percent which goes on a longgggg ways
==============================
Useful macros
1. Bar
/Bar {
percent args
/drop exch def
/endheight exch 2 div def
/length exch 2 div def
/ypos exch def /xpos exch def
percent draw
xpos ypos moveto
length endheight rmoveto
0 -2 endheight mul rlineto
0 endheight rmoveto
-2 length mul 0 rlineto
0 endheight rlineto
0 -2 endheight mul rlineto
percent label
xpos ypos moveto
dup stringwidth pop
2 div neg drop rmoveto
show stroke
} def
Takes a string, bar x and y center coordinate, bar full length,
end-bar full length and character y offset as its arguments. You are
responsible for setlinewidth, setrgbcolor/setgray, and setfont in
advance of this command as well. Thus
newpath
/Helvetica-Bold findfont 33 scalefont setfont
4 setlinewidth 0 2.8 0.8 setrgbcolor
(1 pc) 950 2100 173.4 30 14 Bar
Copy the /Bar definition to the definition section of your AIPS plot,
copy some text such as the example above to just before the end of
your AIPS plot (just ahead of "vmsave restore showpage") and then look
at it with gv. Adjust the parameters to make the most pleasing (and
correct) display. It looks more complicated than it is.
2. Arrow
/arrowdict 14 dict def
arrowdict begin
/mtrx matrix def
end
/arrow
{arrowdict begin
percent pick args off stack
/headlength exch def
/halfheadthick exch 2 div def
/halfthick exch 2 div def
/tipy exch def /tipx exch def
/taily exch def /tailx exch def
percent internal parms
/dx tipx tailx sub def
/dy tipy taily sub def
/arrowlength dx dx mul dy dy mul add sqrt def
/angle dy dx atan def
/base arrowlength headlength sub def
percent save state
/savematrix mtrx currentmatrix def
percent set local coords
tailx taily translate angle rotate
percent draw arrow
0 halfthick neg moveto
base halfthick neg lineto
base halfheadthick neg lineto
arrowlength 0 lineto
base halfheadthick lineto
base halfthick lineto
0 halfthick lineto
closepath
percent restore state
savematrix setmatrix
end
} def
Useage:
7 Arguments are
x y of center of tail
x y of arrow tip
tail thickness
max arrow head thickness
length of arrowhead
Examples:
percent black arrow to left
newpath
318 340 72 340 10 30 72 arrow
0 setgray fill
percent outline arrow to upper right
newpath
382 400 542 560 72 232 116 arrow
3 setlinewidth stroke
percent grey and outline arrow down
newpath
400 300 400 90 90 200 200 3 sqrt mul 2 div arrow
gsave .65 setgray fill grestore
5 setlinewdith stroke
percent Example from aips plot file
newpath
900 1700 1100 1700 9 17 30 arrow
1 setgray fill
newpath
902 1700 1098 1700 3 11 28 arrow
0 setgray fill
stroke
newpath
860 1690 moveto 1 .5 0 setrgbcolor
(a) show stroke
COMBINING TWO POSTSCRIPT FILES
Sometimes, one would like to combine two independent plots in AIPS
into one PostScript file for inclusion in a talk or paper. In
particular, task HUINT can make a "true-color" image plus a
two-dimensional true-color step wedge. KNTR or GREYS (with LTYPE=7
to reduce the extraneous text lines) plus LWPLA can then make two
PostScript files which one would like to combine into a single file.
Exactly what one does to do this will depend on what one wants to get
in the end, so keep looking at the plot in ghostview at every step in
the process.
1. Simply append the wedge PostScript file at the end of the image
file to start with.
2. At the beginning is a set of commands, 1 "moveto", 4 "lineto"'s,
followed by a "fill stroke". This sets the background color which you
may wish to change from black by putting a
r g b setrgbcolor
command ahead of the moveto - e.g.
1.000 1.000 1.000 setrgbcolor
150 742 moveto 2400 742 lineto 2400 2554 lineto
150 2554 lineto 150 742 lineto fill stroke
for a white background.
3. With color and grey-scale images, AIPS first draws the multi-bit
image and then paints the labeling (so that the tick marks will be on
top of the image and hence visible.) Thus, the (large) image
grey-scale section of the file may be skipped over in the editor by
searching for, e.g., the string "Declination". The string Declination
will get you to the axis labeling. You may wish to add more
setrgbcolor commands here - e.g. 1 1 1 setrgbcolor ahead of the "v"
commands drawing tics inside the plot followed by 0 0 0 setrgbcolor
ahead of the commands writing text outside the image:
570 944 m 1.000 1.000 1.000 setrgbcolor 569 900 v
569 900 m 0.000 0.000 0.000 setrgbcolor
(17 52) 0 -113 -62 c
4. Working through the concatenated file, following the image
labeling, you will encounter the trailing comments from the image
PostScript file and preliminary somments from the wedge file. Delete
these. Thus the end of the image plot - start of the wedge plot will
look something like:
2306 2013 m 2350 2014 v
2306 1705 m 2350 1706 v
2306 1397 m 2350 1397 v
2306 1089 m 2350 1089 v
stroke
percent step wedge addition
0 1000 translate
percent Start grey-scale at plane 1
1 4 m 413 1547 m
/hafpix -2 def
/hafpiy -2 def
/pscalx 1937 def
/pscaly 4 def
/npix 620 def
G
00020A00061600071C000820000923000A26000A29000B2B000C2D000C2F000D31000D33
where the first four lines are right hand tick marks, "stroke"
completes the image section, the "0 x translate" is added to move the
wedge above the image, and the remainder shows the first lines of the
wedge file retained in the combined file.
The translate means that we do not have to change other Y position
values, they are now wrt that translation point (which may need
adjusting).
5. The wedge labeling comes at the end of the wedge grey-scale values
- i.e. almost at the end of your combined PostScript file. You will
probably want to change the axis label strings. The "c" command has 4
arguments - the string in parentheses, the angle, an X, and a Y
offset. To change the vertical label, change the string and the Y
offset (to center it again). The horizontal tick labels and axis
label may well want to move to the top of the wedge from the bottom.
Thus:
(Kilo JY/B INT) 0 -158 -116 c
413 1544 m
413 1572 m 1.000 1.000 1.000 setrgbcolor 413 1544 v
413 1544 m 0.000 0.000 0.000 setrgbcolor
(0.0) 0 -59 -62 c
became, in the final file,
(Kilo Jy/Beam Intensity) 0 -258 72 c
413 1544 m
413 1572 m 1.000 1.000 1.000 setrgbcolor 413 1544 v
413 1860 m 0.000 0.000 0.000 setrgbcolor
(0.0) 0 -59 12 c
Note that we leave the "m" commands alone and just change the offset
(in the "c" command) from those reference positions.
7. Finally at the end of the file, the upper Y value (4'th value) of
the " percent percentBoundingBox:" command will need to be increased to include the
full size of the image and wedge.
8. Keep checking your changes with gv (ghostview) to make sure they
are what you want. Re-set BoundingBox to include everything but
without too much white around the edges.
9. If you choose to change the font size or type, you will probably
want to change the offsets. LWPLA chooses offsets based on the font
type and size it uses, so they are in general not correct for some
significantly different font size.
REFERENCES
PostScript Language Reference Manual, Second Edition
Adobe Systems Incorporated
Addison-Wesley, 1990
ISBN 0-201-18127-4
Arrow above from
PostScript Language Tutorial and Cookbook
Adobe Systems Incorporated
Addison-Wesley, 1986
ISBN 0-201-10179-3
STUFF TO KEEP LAWYERS HAPPY
PostScript is a registered trademark of Adobe Systems Incorporated.