ref: 7bffa51339030289a8d88d5171f3774d75cb31a0
dir: /sys/src/cmd/plot/libplot/disk.c/
#include "mplot.h"
void plotdisc(double xc, double yc, double r){
Point p;
int rad;
p.x=SCX(xc);
p.y=SCY(yc);
if (r < 0)
rad=SCR(-r);
else
rad=SCR(r);
m_disc(p, rad, e1->foregr);
}