Why not?

src/cmd/map/symbol.c

@@ -0,0 +1,192 @@
+#include <u.h>
+#include <libc.h>
+#include <stdio.h>
+#include "map.h"
+#include "iplot.h"
+
+#define NSYMBOL 20
+
+enum flag { POINT,ENDSEG,ENDSYM };
+struct symb {
+	double x, y;
+	char name[10+1];
+	enum flag flag;
+} *symbol[NSYMBOL];
+
+static int nsymbol;
+static double halfrange = 1;
+extern int halfwidth;
+extern int vflag;
+
+static int	getrange(FILE *);
+static int	getsymbol(FILE *, int);
+static void	setrot(struct place *, double, int);
+static void	dorot(struct symb *, double *, double *);
+
+
+void
+getsyms(char *file)
+{
+	FILE *sf = fopen(file,"r");
+	if(sf==0)
+		filerror("cannot open", file);
+	while(nsymbol<NSYMBOL-1 && getsymbol(sf,nsymbol))
+		nsymbol++;
+	fclose(sf);
+}
+
+static int
+getsymbol(FILE *sf, int n)
+{
+	double x,y;
+	char s[2];
+	int i;
+	struct symb *sp;
+	for(;;) {
+		if(fscanf(sf,"%1s",s)==EOF)
+			return 0;
+		switch(s[0]) {
+		case ':':
+			break;
+		case 'o':
+		case 'c':	/* cl */
+			fscanf(sf,"%*[^\n]");
+			continue;
+		case 'r':
+			if(getrange(sf))
+				continue;
+		default:
+			error("-y file syntax error");
+		}
+		break;
+	}
+	sp = (struct symb*)malloc(sizeof(struct symb));
+	symbol[n] = sp;
+	if(fscanf(sf,"%10s",sp->name)!=1)
+		return 0;
+	i = 0;
+	while(fscanf(sf,"%1s",s)!=EOF) {
+		switch(s[0]) {
+		case 'r':
+			if(!getrange(sf))
+				break;
+			continue;
+		case 'm':
+			if(i>0)
+				symbol[n][i-1].flag = ENDSEG;
+			continue;
+		case ':':
+			ungetc(s[0],sf);
+			break;
+		default:
+			ungetc(s[0],sf);
+		case 'v':
+			if(fscanf(sf,"%lf %lf",&x,&y)!=2)
+				break;
+			sp[i].x = x*halfwidth/halfrange;
+			sp[i].y = y*halfwidth/halfrange;
+			sp[i].flag = POINT;
+			i++;
+			sp = symbol[n] = (struct symb*)realloc(symbol[n],
+					(i+1)*sizeof(struct symb));
+			continue;
+		}
+		break;
+	}
+	if(i>0)
+		symbol[n][i-1].flag = ENDSYM;
+	else
+		symbol[n] = 0;
+	return 1;
+}
+
+static int
+getrange(FILE *sf)
+{
+	double x,y,xmin,ymin;
+	if(fscanf(sf,"%*s %lf %lf %lf %lf",
+		&xmin,&ymin,&x,&y)!=4)
+		return 0;
+	x -= xmin;
+	y -= ymin;
+	halfrange = (x>y? x: y)/2;
+	if(halfrange<=0)
+		error("bad ra command in -y file");
+	return 1;
+}
+
+/* r=0 upright;=1 normal;=-1 reverse*/
+int
+putsym(struct place *p, char *name, double s, int r)
+{
+	int x,y,n;
+	struct symb *sp;
+	double dx,dy;
+	int conn = 0;
+	for(n=0; symbol[n]; n++)
+		if(strcmp(name,symbol[n]->name)==0)
+			break;
+	sp = symbol[n];
+	if(sp==0)
+		return 0;
+	if(doproj(p,&x,&y)*vflag <= 0)
+		return 1;
+	setrot(p,s,r);
+	for(;;) {
+		dorot(sp,&dx,&dy);
+		conn = cpoint(x+(int)dx,y+(int)dy,conn);
+		switch(sp->flag) {
+		case ENDSEG:
+			conn = 0;
+		case POINT:
+			sp++;
+			continue;
+		case ENDSYM:
+			break;
+		}
+		break;
+	}
+	return 1;
+}
+
+static double rot[2][2];
+
+static void
+setrot(struct place *p, double s, int r)
+{
+	double x0,y0,x1,y1;
+	struct place up;
+	up = *p;
+	up.nlat.l += .5*RAD;
+	sincos(&up.nlat);
+	if(r&&(*projection)(p,&x0,&y0)) {
+		if((*projection)(&up,&x1,&y1)<=0) {
+			up.nlat.l -= RAD;
+			sincos(&up.nlat);
+			if((*projection)(&up,&x1,&y1)<=0)
+				goto unit;
+			x1 = x0 - x1;
+			y1 = y0 - y1;
+		} else {
+			x1 -= x0;
+			y1 -= y0;
+		}
+		x1 = r*x1;
+		s /= hypot(x1,y1);
+		rot[0][0] = y1*s;
+		rot[0][1] = x1*s;
+		rot[1][0] = -x1*s;
+		rot[1][1] = y1*s;
+	} else {
+unit:
+		rot[0][0] = rot[1][1] = s;
+		rot[0][1] = rot[1][0] = 0;
+	}
+}
+
+static void
+dorot(struct symb *sp, double *px, double *py)
+{
+	*px = rot[0][0]*sp->x + rot[0][1]*sp->y;
+	*py = rot[1][0]*sp->x + rot[1][1]*sp->y;
+}