cameo: added KiCad Gerber input and path merging

- Makefile (OBJS): added gerber.o
- cameo.c (usage, main): new option -g to process input a KiCad Gerber
- gerber.h, gerber.c (gerber_read): parse Gerber files as generated by KiCad
- path.h, path.c (path_reverse_inplace, points_eq, attr_eq, path_connect):
  merge sets of paths with equal endpoints into single paths

cameo/Makefile

@@ -15,7 +15,7 @@ PREFIX ?= /usr/local
 SHELL=/bin/bash
 
 MAIN=cameo
-OBJS=cameo.o gnuplot.o path.o
+OBJS=cameo.o gerber.o gnuplot.o path.o
 
 CFLAGS_WARN=-Wall -Wshadow -Wmissing-prototypes \
             -Wmissing-declarations -Wno-format-zero-length

cameo/cameo.c

@@ -17,6 +17,7 @@
 
 #include "path.h"
 #include "gnuplot.h"
+#include "gerber.h"
 
 
 static int dog_bone = 0;
@@ -65,9 +66,11 @@ static void process_paths(struct path *paths)
 static void usage(const char *name)
 {
 	fprintf(stderr,
-"usage: %s [-d] r_mm [in.gnuplot [out.gnuplot]]\n\n"
+"usage: %s [-d] r_mm [in.gnuplot [out.gnuplot]]\n"
+"       %s -g [-d] r_mm [in.gerber [out.gnuplot]]\n\n"
 "  -d  put a dog-bone notch in each concave external corner\n"
-    , name);
+"  -g  input format is KiCad Gerber, not gnuplot\n"
+    , name, name);
 	exit(1);
 }
 
@@ -75,15 +78,19 @@ static void usage(const char *name)
 int main(int argc, char **argv)
 {
 	char *in = NULL, *out = NULL;
+	int gerber = 0;
 	double r;
 	struct path *paths;
 	int c;
 
-	while ((c = getopt(argc, argv, "d")) != EOF)
+	while ((c = getopt(argc, argv, "dg")) != EOF)
 		switch (c) {
 		case 'd':
 			dog_bone = 1;
 			break;
+		case 'g':
+			gerber = 1;
+			break;
 		default:
 			usage(*argv);
 		}
@@ -102,7 +109,10 @@ int main(int argc, char **argv)
 		usage(*argv);
 	}
 
-	paths = gnuplot_read(in, r);
+	if (gerber)
+		paths = gerber_read(in, r);
+	else
+		paths = gnuplot_read(in, r);
 	process_paths(paths);
 	gnuplot_write(out, paths);
 

cameo/gerber.c

@@ -0,0 +1,93 @@
+/*
+ * gerber.c - Gerber file input
+ *
+ * Written 2010 by Werner Almesberger
+ * Copyright 2010 Werner Almesberger
+ *
+ * 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.
+ */
+
+/*
+ * Note: this is limited to the Gerber produced by KiCad for the PCB Edge
+ * layer. Furthermore, we ignore the tool diameter for now.
+ *
+ * The relevant details are nicely explained at
+ * http://www.pcbmilling.com/Examples of Gerber and Excellon Data Files.htm
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "path.h"
+#include "gerber.h"
+
+
+/* KiCad Gerber uses 0.1 mil units */
+
+#define	KU2MM(in)	((in)/10000.0*25.4)
+
+
+struct path *gerber_read(const char *name, double r_tool_default)
+{
+	FILE *file;
+	int lineno = 0;
+	char buf[1024];
+	struct path *paths = NULL, **anchor = &paths, *path = NULL;
+	int start_x = 0, start_y = 0;
+	int x, y, d;
+
+	file = name ? fopen(name, "r") : stdin;
+	if (!file) {
+		perror(name);
+		exit(1);
+	}
+
+	while (fgets(buf, sizeof(buf), file)) {
+		lineno++;
+		if (!strncmp(buf, "%FS", 3)) {
+			if (strcmp(buf, "%FSLAX34Y34*%\n")) {
+				fprintf(stderr,
+				    "unrecognized format %s\n", buf);
+				exit(1);
+			}
+			continue;
+		}
+		if (!strncmp(buf, "%MO", 3)) {
+			if (strcmp(buf, "%MOIN*%\n")) {
+				fprintf(stderr,
+				    "unrecognized mode %s\n", buf);
+				exit(1);
+			}
+			continue;
+		}
+		if (sscanf(buf, "X%dY%dD%d*\n", &x, &y, &d) != 3)
+			continue;
+		x = KU2MM(x);
+		y = KU2MM(y);
+		switch (d) {
+		case 1:
+			if (!path) {
+				path = path_new(r_tool_default);
+				*anchor = path;
+				anchor = &path->next;
+				path_add(path, start_x, start_y, 0);
+			}
+			path_add(path, x, y, 0);
+			break;
+		case 2:
+			path = NULL;
+			start_x = x;
+			start_y = y;
+			break;
+		default:
+			fprintf(stderr, "don't recognize D%d\n", d);
+			exit(1);
+		}
+	}
+	fclose(file);
+	return path_connect(paths);
+}

cameo/gerber.h

@@ -0,0 +1,22 @@
+/*
+ * gerber.h - Gerber file input
+ *
+ * Written 2010 by Werner Almesberger
+ * Copyright 2010 Werner Almesberger
+ *
+ * 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.
+ */
+
+#ifndef GERBER_H
+#define GERBER_H
+
+#include "path.h"
+
+
+struct path *gerber_read(const char *name, double r_tool_default);
+
+#endif /* !GERBER_H */
+

cameo/path.c

@@ -147,6 +147,20 @@ struct path *path_reverse(const struct path *path)
 }
 
 
+static void path_reverse_inplace(struct path *path)
+{
+	struct point *points = NULL, *p, *next;
+
+	path->last = path->first;
+	for (p = path->first; p; p = next) {
+		next = p->next;
+		p->next = points;
+		points = p;
+	}
+	path->first = points;
+}
+
+
 static struct point *offset_point(const struct point *a, const struct point *b,
     const struct point *c, double off, int left)
 {
@@ -331,3 +345,54 @@ struct path *path_find_leftmost(struct path *path)
 	}
 	return best;
 }
+
+
+static int points_eq(const struct point *a, const struct point *b)
+{
+	return a->x == b->x && a->y == b->y && a->z == b->z;
+}
+
+
+static int attr_eq(const struct path *a, const struct path *b)
+{
+	return a->r_tool == b->r_tool && a->outside == b->outside &&
+	    a->notch == b->notch;
+}
+
+
+struct path *path_connect(struct path *path)
+{
+	struct path **a, **b;
+	struct path *tmp;
+
+again:
+	for (a = &path; *a; a = &(*a)->next)
+		for (b = &(*a)->next; *b; b = &(*b)->next) {
+			if (!attr_eq(*a, *b))
+				continue;
+			if (points_eq((*a)->last, (*b)->last))
+				path_reverse_inplace(*b);
+			if (points_eq((*a)->last, (*b)->first)) {
+				(*a)->last->next = (*b)->first->next;
+				(*a)->last = (*b)->last;
+				free((*b)->first);
+				tmp = *b;
+				*b = tmp->next;
+				free(tmp);
+				goto again;
+			}
+			if (points_eq((*a)->first, (*b)->first))
+				path_reverse_inplace(*b);
+			if (points_eq((*a)->first, (*b)->last)) {
+				(*b)->last->next = (*a)->first->next;
+				(*b)->last = (*a)->last;
+				free((*a)->first);
+				tmp = *a;
+				*a = *b;
+				free(tmp);
+				*b = (*b)->next;
+				goto again;
+			}
+		}
+	return path;
+}

cameo/path.h

@@ -37,5 +37,6 @@ int path_tool_is_left(const struct path *path);
 struct path *path_offset(const struct path *path, int left, int notch);
 struct path *path_find_leftmost(struct path *path);
 void path_free(struct path *path);
+struct path *path_connect(struct path *path);
 
 #endif /* !PATH_H */