Edit: /usr/share/graphviz/gvpr/rotate (1194B)
/* Given node name and angle, rotate a layout using the given
* node as origin.
*/
BEGIN {
double x,y;
double x0,y0;
double x1,y1;
double angle, cosa, sina;
int cnt, sz;
void rotate (double a, double b) {
a -= x0;
b -= y0;
x1 = a*cosa - b*sina;
y1 = a*sina + b*cosa;
}
char* rotateE (char* p) {
char* newpos = "";
cnt = sscanf (p, "e,%lf,%lf%n", &x, &y, &sz);
if (cnt == 2) {
rotate (x,y);
newpos = newpos + sprintf ("e%lf,%lf ", x1, y1);
p = substr(p, sz);
}
cnt = sscanf (p, "s,%lf,%lf%n", &x, &y, &sz);
if (cnt == 2) {
rotate (x,y);
newpos = newpos + sprintf ("s%lf,%lf ", x1, y1);
p = substr(p, sz);
}
while (sscanf (p, "%lf,%lf%n", &x, &y, &sz) == 2) {
rotate (x,y);
newpos = newpos + sprintf ("%lf,%lf ", x1, y1);
p = substr(p, sz);
}
return newpos;
}
}
BEG_G {
node_t ctr = node ($, ARGV[0]);
sscanf (ARGV[1], "%f", &angle);
cosa = cos(angle);
sina = sin(angle);
sscanf (ctr.pos, "%f,%f", &x0, &y0);
$.bb ="";
}
N {
sscanf ($.pos, "%f,%f", &x, &y);
rotate (x,y);
$.pos = sprintf ("%f,%f", x1, y1);
}
E {
$.pos = rotateE($.pos);
}