Convert a Calcomp plot file to SVG.

Author: larsbrinkhoff

.gitignore

@@ -2,6 +2,7 @@
 *.o
 *.dSYM
 acct
+calcomp
 cat36
 check
 classify-tape

Makefile

@@ -11,10 +11,10 @@ LIBWORD = libword/libword.a
 OBJS =	pdp10-opc.o info.o dis.o symbols.o \
 	timing.o timing_ka10.o timing_ki10.o memory.o weenix.o
 
-UTILS = acct cat36 classify-tape constantinople cross dart dskdmp	\
-        dump dumper harscntopbm ipak itsarc kldcp klfedr linum macdmp	\
-        macro-tapes magdmp magfrm mini-dumper od10 old-cpio palx plt	\
-        scrmbl tape-dir tendmp tito tvpic unscr
+UTILS = acct calcomp cat36 classify-tape constantinople cross dart	\
+        dskdmp dump dumper harscntopbm ipak itsarc kldcp klfedr linum	\
+        macdmp macro-tapes magdmp magfrm mini-dumper od10 old-cpio	\
+        palx plt scrmbl tape-dir tendmp tito tvpic unscr
 
 all: dis10 $(UTILS) check
 
@@ -83,6 +83,9 @@ tito: tito.o $(OBJS) $(LIBWORD)
 plt: plt.o svg.o $(OBJS) $(LIBWORD)
 	$(CC) $(CFLAGS) $^ -o $@
 
+calcomp: calcomp.o svg.o $(OBJS) $(LIBWORD)
+	$(CC) $(CFLAGS) $^ -o $@
+
 dart: dart.o dec.o $(OBJS) $(LIBWORD)
 	$(CC) $(CFLAGS) $^ -o $@
 

README.md

@@ -28,6 +28,7 @@ is elsewhere: http://github.com/larsbrinkhoff/mldev
 - Extract files from a DECtape image in TENDMP/DTBOOT format.
 - Create a TENDMP/DTBOOT image.
 - Print entried in a WAITS accounting file.
+- Convert a Calcomp plot file to SVG.
 
 ## File formats supported.
 

calcomp.c

@@ -0,0 +1,86 @@
+/* Copyright (C) 2025 Lars Brinkhoff <lars@nocrew.org>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+//#include <unistd.h>
+#include "dis.h"
+#include "svg.h"
+
+static int x, y;
+static void (*plot)(FILE *f, int x, int y);
+
+static void fatal(const char *message)
+{
+  fputs(message, stderr);
+  exit(1);
+}
+
+static void just_move(FILE *f, int x, int y)
+{
+  (void)f;
+  (void)x;
+  (void)y;
+}
+
+static void process(int data)
+{
+  if ((data & 060) == 060)
+    fatal ("Pen both up and down.");
+  if (data & 040) {
+    if (plot != just_move)
+      svg_polyline_end(stdout);
+    plot = just_move;
+  }
+  if (data & 020) {
+    if (plot == just_move)
+      plot = svg_polyline_begin;
+  }
+  if (data & 010)
+    y--;
+  if (data & 004)
+    y++;
+  if (data & 002)
+    x--;
+  if (data & 001)
+    x++;
+  plot (stdout, x, y);
+  if (plot == svg_polyline_begin)
+    plot = svg_polyline_point;
+}
+
+static void calcomp(FILE *f)
+{
+  word_t data;
+  int i;
+
+  for (;;) {
+    data = get_word(f);
+    if (data == -1)
+      return;
+    for (i = 0; i < 6; i++, data <<= 6)
+      process((data >> 30) & 077);
+  }
+}
+
+int main(void)
+{
+  input_word_format = &aa_word_format;
+  x = y = 0;
+  plot = just_move;
+  svg_file_begin(stdout);
+  calcomp(stdin);
+  svg_file_end(stdout);
+  return 0;
+}