#include "mplot.h"void frame(double xs, double ys, double xf, double yf){	register double	osidex, osidey;	osidex = e1->sidex;	osidey = e1->sidey;	e1->left = e0->left + xs * e0->sidex;	e1->bottom = e0->bottom + ys * e0->sidey;	e1->sidex = (xf-xs)*e0->sidex;	e1->sidey = (yf-ys)*e0->sidey;	e1->scalex *= (e1->sidex / osidex);	e1->scaley *= (e1->sidey / osidey);	e1->quantum=e0->quantum/sqrt(e1->scalex*e1->scalex +		e1->scaley*e1->scaley);	if(e1->quantum < .01)		e1->quantum = .01;}