void z2rho(float, float, float*, float*), y2rho(float, float, float*, float*),
  rho2z(float, float, float*, float*),  rho2y(float, float, float*, float*),
  rhoz1z2(float *, float *, float, float);
void rect2polar(float *, float *), polar2rect(float *, float *);
void recalc(void);

float thetaonR(float, float, float), thetaonX(float, float, float), 
  thetaonG(float, float, float), thetaonB(float, float, float);

void float2prefs(float, char *, int);