/* Color mapping appropriate for two-sided data. 
   Zero corresponds to blue.
 */
#include <math.h>

void cmap2(float *h,float *s,float *v,float xpnt) {
  if (xpnt > 0.8) {
    *h = 330. + 30*(1.0-xpnt)/0.2;
    *s = (1.0-xpnt)/0.2;
    *v = 1.0;
  } else {
    if (xpnt < 0.) xpnt = 1.5*xpnt;
    *h = (240.0 + 120.*xpnt);
    *s = 1.0;
    *v = 1.0;
  }
  return;
}