svgpic: new program to convert pic to svg

This is an experiment.
Like tpic it's a copy-and-paste fork of pic.

Change-Id: Ia22772bd5881c7904a6d8f8e0b46fde8cea89cbd
Reviewed-on: https://plan9port-review.googlesource.com/2920
Reviewed-by: Russ Cox <rsc@swtch.com>

1 files changed, 182 insertions, 0 deletions

diff --git a/src/cmd/svgpic/print.c b/src/cmd/svgpic/print.c
new file mode 100644
index 00000000..1be73867
--- /dev/null
+++ b/src/cmd/svgpic/print.c
@@ -0,0 +1,182 @@
+#include <stdio.h>
+#include <math.h>
+#include "pic.h"
+#include "y.tab.h"
+
+void dotext(obj *);
+void ellipse(double, double, double, double);
+void circle(double, double, double);
+void arc(double, double, double, double, double, double, double);
+void arrow(double, double, double, double, double, double, double, int);
+void line(double, double, double, double, int, double);
+void box(double, double, double, double, int, double);
+void spline(double x, double y, double n, ofloat *p, int dashed, double ddval);
+void move(double, double);
+void troff(char *);
+void dot(void);
+void fillstart(double, int, int), fillend(void);
+
+void print(void)
+{
+	obj *p;
+	int i, j, k, m;
+	int fill, vis, invis;
+	double x0, y0, x1, y1, ox, oy, dx, dy, ndx, ndy;
+
+	x1 = y1 = 0.0; /* Botch? (gcc) */
+
+	for (i = 0; i < nobj; i++) {
+		p = objlist[i];
+		ox = p->o_x;
+		oy = p->o_y;
+		if (p->o_count >= 1)
+			x1 = p->o_val[0];
+		if (p->o_count >= 2)
+			y1 = p->o_val[1];
+		m = p->o_mode;
+		fill = p->o_attr & FILLBIT;
+		invis = p->o_attr & INVIS;
+		vis = !invis;
+		switch (p->o_type) {
+		case TROFF:
+			troff(text[p->o_nt1].t_val);
+			break;
+		case BOX:
+		case BLOCK:
+			x0 = ox - x1 / 2;
+			y0 = oy - y1 / 2;
+			x1 = ox + x1 / 2;
+			y1 = oy + y1 / 2;
+			if (fill) {
+				move(x0, y0);
+				fillstart(p->o_fillval, vis, fill);
+			}
+			if (p->o_type == BLOCK)
+				;	/* nothing at all */
+			else if (invis && !fill)
+				;	/* nothing at all */
+			else
+				box(x0, y0, x1, y1, p->o_attr & (DOTBIT|DASHBIT), p->o_ddval);
+			if (fill)
+				fillend();
+			move(ox, oy);
+			dotext(p);	/* if there are any text strings */
+			if (ishor(m))
+				move(isright(m) ? x1 : x0, oy);	/* right side */
+			else
+				move(ox, isdown(m) ? y0 : y1);	/* bottom */
+			break;
+		case BLOCKEND:
+			break;
+		case CIRCLE:
+			if (fill)
+				fillstart(p->o_fillval, vis, fill);
+			if (vis || fill)
+				circle(ox, oy, x1);
+			if (fill)
+				fillend();
+			move(ox, oy);
+			dotext(p);
+			if (ishor(m))
+				move(ox + isright(m) ? x1 : -x1, oy);
+			else
+				move(ox, oy + isup(m) ? x1 : -x1);
+			break;
+		case ELLIPSE:
+			if (fill)
+				fillstart(p->o_fillval, vis, fill);
+			if (vis || fill)
+				ellipse(ox, oy, x1, y1);
+			if (fill)
+				fillend();
+			move(ox, oy);
+			dotext(p);
+			if (ishor(m))
+				move(ox + isright(m) ? x1 : -x1, oy);
+			else
+				move(ox, oy - isdown(m) ? y1 : -y1);
+			break;
+		case ARC:
+			if (fill) {
+				move(ox, oy);
+				fillstart(p->o_fillval, vis, fill);
+			}
+			if (p->o_attr & HEAD1)
+				arrow(x1 - (y1 - oy), y1 + (x1 - ox),
+				      x1, y1, p->o_val[4], p->o_val[5], p->o_val[5]/p->o_val[6]/2, p->o_nhead);
+			if (invis && !fill)
+				/* probably wrong when it's cw */
+				move(x1, y1);
+			else
+				arc(ox, oy, x1, y1, p->o_val[2], p->o_val[3], p->o_val[6]);
+			if (p->o_attr & HEAD2)
+				arrow(p->o_val[2] + p->o_val[3] - oy, p->o_val[3] - (p->o_val[2] - ox),
+				      p->o_val[2], p->o_val[3], p->o_val[4], p->o_val[5], -p->o_val[5]/p->o_val[6]/2, p->o_nhead);
+			if (fill)
+				fillend();
+			if (p->o_attr & CW_ARC)
+				move(x1, y1);	/* because drawn backwards */
+			move(ox, oy);
+			dotext(p);
+			break;
+		case LINE:
+		case ARROW:
+		case SPLINE:
+			if (fill) {
+				move(ox, oy);
+				fillstart(p->o_fillval, vis, fill);
+			}
+			if (vis && p->o_attr & HEAD1)
+				arrow(ox + p->o_val[5], oy + p->o_val[6], ox, oy, p->o_val[2], p->o_val[3], 0.0, p->o_nhead);
+			if (invis && !fill)
+				move(x1, y1);
+			else if (p->o_type == SPLINE)
+				spline(ox, oy, p->o_val[4], &p->o_val[5], p->o_attr & (DOTBIT|DASHBIT), p->o_ddval);
+			else {
+				dx = ox;
+				dy = oy;
+				for (k=0, j=5; k < p->o_val[4]; k++, j += 2) {
+					ndx = dx + p->o_val[j];
+					ndy = dy + p->o_val[j+1];
+					line(dx, dy, ndx, ndy, p->o_attr & (DOTBIT|DASHBIT), p->o_ddval);
+					dx = ndx;
+					dy = ndy;
+				}
+			}
+			if (vis && p->o_attr & HEAD2) {
+				dx = ox;
+				dy = oy;
+				for (k = 0, j = 5; k < p->o_val[4] - 1; k++, j += 2) {
+					dx += p->o_val[j];
+					dy += p->o_val[j+1];
+				}
+				arrow(dx, dy, x1, y1, p->o_val[2], p->o_val[3], 0.0, p->o_nhead);
+			}
+			if (fill)
+				fillend();
+			move((ox + x1)/2, (oy + y1)/2);	/* center */
+			dotext(p);
+			break;
+		case MOVE:
+			move(ox, oy);
+			break;
+		case TEXT:
+			move(ox, oy);
+                        if (vis)
+				dotext(p);
+			break;
+		}
+	}
+}
+
+void dotext(obj *p)	/* print text strings of p in proper vertical spacing */
+{
+	int i, nhalf;
+	void label(char *, int, int);
+
+	nhalf = p->o_nt2 - p->o_nt1 - 1;
+	for (i = p->o_nt1; i < p->o_nt2; i++) {
+		label(text[i].t_val, text[i].t_type, nhalf);
+		nhalf -= 2;
+	}
+}