Laser-Lovers-Request@WASHINGTON.ARPA (Moderator) (01/12/86)
Info-Postscript for Laser Lovers DigestSunday, January 12, 1986 11:34AM
Volume 1, Issue 5
Today's Topics:
Plot (3) filter to PostScript
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From: decvax!J.Rapaport@S.ARPA, decvax!Grouptheory.Systems.Inc.@seismo.CSS.GOV
Date: Thu Dec 5 11:17:09 EST 1985
Subject: Plot (3) filter to PostScript
--------------
Dear Richard: I am sending you a copy of the source for a bridge to
the apple LaserWriter (and any other PostScript engine) that will take
output from any C program using the plot(3) library. Full documentation
is included in the comments. If you think this might be of help to others
on the net, feel welcome to post it. It is called "tlw", to match the
naming convention of the other tplot filters.
In addition, I have included a small C program ("margtest.c") for testing tlw.
It draws a box around the page, near the margin that the LaserWriter
imposes. Since tlw likes to know the location of this margin, which differs
from machine to machine, "margtest" is an aid to determining the margin
on a given laserwriter (and perhaps, toner cartridge). There are
#define's in the source of tlw that can be altered to indicate the location
of your margins. See the comments in the source.
Thanks,
Steve Rapaport
{decvax, etc...} !utzoo!dciem!nrcaer!grpthry!rap
"Bottom-up Programming: If it was good enough for God..."
First, the test program, margtest.c:
------------------------- cut here ----------------------------------------
/* this is just a test program to find out where the margins are on your
* laserwriter. Run it and send the output through tlw to the laserwriter.
* it should draw a (perfectly) square box with dashed diagonals.
* Adjust MARGX and MARGY in tlw until the edges of the box are just visible.
*/
#include <stdio.h>
#define BLEFT 0, 0
#define TLEFT 0, 4096
#define BRIGHT 4096, 0
#define TRIGHT 4096, 4096
main ()
{
openpl ();
space (BLEFT, TRIGHT);
linemod ("longdashed");
line (BLEFT, TRIGHT);
linemod ("shortdashed");
line (BRIGHT, TLEFT);
linemod ("solid");
move (BLEFT);
cont (TLEFT);
cont (TRIGHT);
cont (BRIGHT);
cont (BLEFT);
closepl ();
}
------------------------- cut here ----------------------------------------
Then, the bridge (tlw.c):
------------------------- cut here ----------------------------------------
/* The following program may be used, copied, and modified by anyone at will,
* so long as this message is not removed or altered.
* 'tlw' was written by Steve Rapaport at grouptheory systems inc., October 85.
* {decvax, etc...}!utzoo!dciem!nrcaer!grpthry!rap
* Copyright 1985 grouptheory systems inc. Permission to reproduce & update
* granted.
*/
/*
*
* tlw -- a filter to turn output from plot(3) library routines into postscript
* instructions for the Apple LaserWriter. (or any PostScript device).
* Compatible with all Berkeley 4.2 PLOT(5) files. (I think!)
* To install, just compile it with the math library (-lm), and
* put it somewhere that everyone can get at. (e.g. /usr/bin/tlw).
*
* Bugs: until end of Dec '85, mail me at utzoo!dciem!nrcaer!grpthry!rap
* After that, you're on your own....
*
* Example of use: Let 'plotter' be a C program containing
* calls to plot(3) routines. The following command will
* put the output of 'plotter' on the laserwriter:
*
* plotter | tlw | <whatever you use to send PostScript to the lw>
*
* In addition, tlw may be added as a 'terminal' filter to the
* plot(1G) shell script (tplot(1G) in system 3)
* by adding the following line to plot (or tplot):
*
* -Tlw) exec /usr/bin/tlw $* ;;
*
* (or wherever you put this program) and using -Tlw as plot option.
*
* Portability: This program has only been tested on a Plexus P/60
* running System 3. It uses no fancies, though, and outputs plain
* ascii. The only problem I can foresee involves the input of
* plot(5) files.
*
* I am using (int) variables to hold the
* integer parameters; if your C thinks (int) is less than 16 bits,
* change that declaration to (long) in main() and readswpd().
*
* Customization: The program takes no options, but certain macros
* may be changed in the source to customize for your installation.
*
* DEFXSCALE, DEFYSCALE: These are the size of the laserwriter
* raster area, in points. Legal size paper will require
* DEFYSCALE to change to 14.0 * 72.0.
* to use another PostScript device (e.g., some Linotron typesetters)
* change these to match the raster area for your machine.
* *Note* that they are (float). (If these constants are defined
* without decimals, the program will behave *strangely*)
*
* MARGX, MARGY: compensate for the clipping boundaries of
* the laserwriter. They are measured in points, and their
* effect is to reduce the page size to fit within the lw's
* raster area. The numbers given here work okay on my machine,
* you may wish to change them to fit yours.
* MARGX refers to the amount that the short dimension differs
* from 8.5 inches (612 points), and MARGY refers to the
* analagous difference from 11 inches (792 points).
* Note that these constants are (float).
*
* FLIP: For the sake of most graphs, defining FLIP
* flips the x and y axes to make the page wider than it is tall.
* To reverse this effect, undefine FLIP (comment out the #define).
* You may want to keep two versions of the filter in your library,
* named, say, tlwh and tlwv, one with FLIP defined, one not.
*
* FONT, PITCH: These are the parameters that postscript takes.
* 10 point letters seem to fit well with what the standard
* programs expect. You may wish to change them, though. If
* you prefer, say, Helvetica to Times Roman, you might change FONT
* to "/Helvetica". PITCH is assumed integer.
*
* LINEWIDTH : This linewidth (.2 of a point) suits my taste.
* You may have your own opinions. Note that the width is
* independent of the scale of the space. Assumed (float).
*
*/
/*
installation-dependent constants:
(change these at will)
*/
/* if you want plots to come out vertical on the page, comment out next line: */
#define FLIP
#define DEFXSCALE 612.0
#define DEFYSCALE 792.0
#define MARGX 39.0
#define MARGY 20.0
#define FONT "/Times-Roman"
#define PITCH 10
#define LINEWIDTH .2
/*
* change the following at your own peril:
*/
#include <stdio.h>
#include <math.h>
#define FOREVER 1
#define DEGREES * 180.0 / 3.141592654
#define DOTS / scale
#define min(a,b) ( (a < b) ? a : b )
#define MARGSCALE min(( DEFXSCALE - MARGX )/DEFXSCALE, \
( DEFYSCALE - MARGY )/DEFYSCALE)
main()
/* hacker's notes: (if you're reading this far, you are probably one such.)
*
* Program assumes you may use the 'space' scaling function once, many times,
* or not at all. This creates some extra (dumb-looking) PostScript output.
* If you try to optimize, keep this assumption in mind.
*
* Upon finding errors in the input, my version skips up to the next newline
* and continues reading. This is good if you want to put comments into your
* plot (5) files. If not, just making the default case in the switch a
* null switch (comment out the one executable statement in it) will
* ignore each invalid character.
*
* You may notice a strange moveto in the label section. This is my
* (trial-and-error determined) kludge to make the first letter of the
* label come out CENTERED on the current point. Plot seems to expect that.
*
* Erase just erases the current page without printing. I think that's how
* it's supposed to work. If you want it to flush instead, change the
* printf("erasepage\n") to printf("showpage\n");
*
*/
{
int x, y, x2, y2, xc, yc; /* or whatever 16 bits is in your C */
/* if a short int is less than 16 bits */
/* this program won't work unless you */
/* change this declaration. */
float r, ang1, ang2;
float xscale, yscale;
float scale = 1.0;
float newpitch = (float) PITCH;
float newlinew = LINEWIDTH;
char command;
char *dashstyle;
char string [257];
printf ("%% -------------------------------------------------- %%\n");
printf ("%% This is a PostScript (TM) program produced by tlw,\n");
printf ("%% from standard plot(5) output. \n");
printf ("%% (S.J. Rapaport, grouptheory systems, 1985)\n");
printf ("\n\n");
printf ("/tlwcontext save def\n");
printf ("%f setlinewidth\n", LINEWIDTH);
printf ("%s findfont %d scalefont setfont\n",FONT, PITCH);
initcoords ();
do {
command = getchar();
switch (command)
{
default: /* if invalid command char, skip rest of line */
/* This is good if you want to put comments into your
plot (5) files. If not, just commenting out the
next line will ignore each invalid character.
*/
if (! gets(string)) fin (0);
break;
case 'm': /* move (x, y) */
readswpd (&x, stdin);
readswpd (&y, stdin);
printf ("%d %d moveto\n",x, y);
break;
case 'n': /* cont (x, y) */
readswpd (&x, stdin);
readswpd (&y, stdin);
printf ("%d %d lineto\n", x, y);
printf ("currentpoint stroke moveto\n");
break;
case 'p': /* point (x, y) */
readswpd (&x, stdin);
readswpd (&y, stdin);
printf ("gsave \n");
printf ("1 setlinecap\n");
printf ("currentlinewidth 2 mul setlinewidth\n");
printf ("%d %d moveto\n", x, y);
printf ("0 0 rlineto\n");
printf ("stroke\n");
printf ("grestore\n");
break;
case 'a': /* arc (xc, yc, x, y, x2, y2) */
readswpd (&xc, stdin);
readswpd (&yc, stdin);
readswpd (&x, stdin);
readswpd (&y, stdin);
readswpd (&x2, stdin);
readswpd (&y2, stdin);
r = sqrt ((float) ((x-xc) * (x-xc) + (y-yc) * (y-yc)));
ang1 = atan ( (float) (y-yc) / (float) (x-xc) ) DEGREES;
ang2 = atan ( (float) (y2-yc) / (float) (x2-xc) ) DEGREES;
if ((x - xc) < 0) ang1 = 180.0 + ang1;
if ((x2 - xc) < 0) ang2 = 180.0 + ang2;
printf ("newpath \n");
printf ("%d %d %6.3f %6.3f %6.3f arc\n", xc, yc, r, ang1, ang2);
printf ("currentpoint stroke moveto\n");
break;
case 'c': /* circle (xc, yc, r) */
readswpd (&xc, stdin);
readswpd (&yc, stdin);
readswpd (&x, stdin);
printf ("newpath \n");
printf ("%d %d %d 0 360 arc\n", xc, yc, x);
printf ("currentpoint stroke moveto\n");
break;
case 'l': /* line (x, y, x2, y2) */
readswpd (&x, stdin);
readswpd (&y, stdin);
readswpd (&x2, stdin);
readswpd (&y2, stdin);
printf ("%d %d moveto\n", x, y);
printf ("%d %d lineto\n", x2, y2);
printf ("currentpoint stroke moveto\n");
break;
case 't': /* label ( string ) */
if (! gets(string) ) fin (0);
printf ("%6.3f %6.3f rmoveto\n", -newpitch/4, -newpitch/4);
printf ("\t(%s) show\n", string);
printf ("%6.3f %6.3f rmoveto\n", newpitch/4, newpitch/4);
break;
case 'e': /* erase () */
printf ("erasepage\n"); /* just erase current page */
break;
case 'f': /* linemod(dashstyle) */
if (! gets(string) ) fin (0);
dashstyle = string;
if (strcmp (dashstyle, "dotted") == 0) {
printf("[%6.3f %6.3f] 0 setdash\n", 1 DOTS, 4 DOTS);
}
else if (strcmp (dashstyle, "solid") == 0) {
printf("[] 0 setdash\n");
}
else if (strcmp (dashstyle, "longdashed") == 0) {
printf("[%6.3f %6.3f] 0 setdash\n", 4 DOTS, 1 DOTS);
}
else if (strcmp (dashstyle, "shortdashed") == 0) {
printf("[%6.3f %6.3f] 0 setdash\n", 2 DOTS, 3 DOTS);
}
else if (strcmp (dashstyle, "dotdashed") == 0) {
printf("[%6.3f %6.3f %6.3f %6.3f] 0 setdash\n",5 DOTS, 2 DOTS, 1 DOTS, 2 DOTS);
}
else break; /* ignore any other styles */
break;
case 's': /* space (x, y, x2, y2) */
readswpd (&x, stdin);
readswpd (&y, stdin);
readswpd (&x2, stdin);
readswpd (&y2, stdin);
xscale = DEFXSCALE / (float) (x2 - x);
yscale = DEFYSCALE / (float) (y2 - y);
scale = (xscale < yscale) ? xscale : yscale; /* min */
newlinew = LINEWIDTH / scale;
newpitch = PITCH / scale;
initcoords();
printf ("%d %d translate\n", -x, -y);
printf ("%6.3f %6.3f scale\n", scale, scale);
printf ("%6.3f setlinewidth\n", newlinew);
printf ("%s findfont ", FONT);
printf ("%6.3f scalefont ", newpitch);
printf ("setfont\n");
break;
} /* end of switch */
} while (FOREVER);
}
initcoords () /* set up coordinate system default (before scaling) */
{
#ifdef FLIP
printf("initmatrix\n");
printf("90 rotate\n");
printf("0 %f translate \n", -DEFXSCALE);
printf("%4.1f %4.1f translate \n", MARGY / 2, MARGX / 2);
printf("%f %f scale \n", MARGSCALE, MARGSCALE);
#else
printf("initmatrix\n");
printf("%4.1f %4.1f translate \n", MARGX / 2, MARGY / 2);
printf("%f %f scale \n", MARGSCALE, MARGSCALE);
#endif
}
readswpd (location, stream)
int *location;
FILE *stream;
{
int nextch;
nextch = getc(stream);
*location = getc(stream);
*location = ((0377 & (*location)) << 8) + (0377 & nextch);
}
fin (error) /* end of input file */
int error;
{
if (! error) /* flush output at end of file */ {
printf ("\nshowpage\n");
printf ("\ntlwcontext restore\n");
}
else /* fatal error (none provided in original source) */
printf ("%% fatal error in input file: no page produced.\n");
exit (error);
}
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End of Info-Postscript for Laser Lovers Digest
**********************************************