ref: 00f7f2ceb6a1818e2975baf6f5c55c1d2d4ecb6e 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); }