ref: 3e9ae26c2ea9c1b0c1bfcc0ad02c58bc65cb5294 dir: /sys/src/cmd/plot/libplot/rvec.c/
#include "mplot.h" void rvec(double xx, double yy){ e1->copyx += xx; e1->copyy += yy; vec(e1->copyx, e1->copyy); }