#define MINSTEPS 100		/* min for locus graph	*/
#define MAXSTEPS 100000		/* max for locus graph	*/
#define FRSTEPS	 100		/* for freq response	*/

#define XYPIXELS 400
#define BORDER	 40
#define TICKLEN	 5
#define PHEPS	 1e-20

union word	/* for error msgs */
{
	int i; void *p;
	word(int ix)   { i = ix; }
	word(void *px) { p = px; }
};

global char *progname;

enum { unknown, locus, phmag, impulse, step } gtype;    /* type of graph */
char *outfn;
double alpha1, alpha2, logmin;
bool logopt, dflag;
double xcoeffs[MAXPZ+1], ycoeffs[MAXPZ+1];
int npoles, nzeros, nirsteps;

void readcmdline(char*[]);
double getfarg(char*);
int getiarg(char*);
void usage();
void drawgraph();
void computefr(complex[], int);
void computeir(double[], int, bool);
void locusgraph(char*, complex[], int, double&);
int xmap_lc(double), ymap_lc(double);
void frgraph(char*, complex[], int);
void irgraph(char*, double[], int);
void pgraph(gdImagePtr, double[], int, int, bool);
void draw_xtick(gdImagePtr, double, double, int, int, char*, double = 0.0);
void draw_ytick(gdImagePtr, double, double, int, int, char*, double = 0.0);
int xmap_pm(double);
int ymap_pm(double);
char *choosefmt(double, double);
int newhandler(size_t size);
void giveup(char*, word = 0);