axis.c

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/*****************************************************************************/
#include "libtpcsvg.h"
/*****************************************************************************/
 
/*****************************************************************************/
int axis_tick_positions(
  const double begin,
  const double end,
  double *ticks,
  int *tick_nr,
  double *scale_factor,
  int *tick_decimals,
  int verbose
) {
  int ti;
  double step, scale;
 
  if(verbose>0)
    printf("axis_tick_positions(%.10E, %.10E, ticks, %d, sf, td, %d)\n", 
      begin, end, *tick_nr, verbose);
 
  /* Check input */
  if(ticks==NULL || *tick_nr<1) return(1);
  //if(verbose>1) printf("  begin:=%.10E\n  end:=%.10E\n", begin, end);
  if(end<=begin) {
    *tick_nr=0;
    if(scale_factor!=NULL) *scale_factor=1.0;
    if(tick_decimals!=NULL) *tick_decimals=0;
    return(0);
  }
  /* Calculate the initial tick step size */
  step=(end-begin)/(double)(*tick_nr);
  if(verbose>1) printf("  tick_nr:=%d\n  step:=%20.10E\n", *tick_nr, step);
 
  /* Calculate a feasible step size and scale */
  scale=1.0;
  while(step<=0.5) {step*=10.0; scale/=10.0;}
  while(step>5.0) {step/=10.0; scale*=10.0;}
  if(verbose>1) printf("  scaled_step:=%.10E\n  scale:=%E\n", step, scale);
  if     (step<1.0) {step=1.0;}
  else if(step<2.0) {step=2.0;}
  else              {step=5.0;}
  if(verbose>1) {
    printf("  feasible step:=%g\n", step);
  }
  ti=0; ticks[ti]=step*scale*ceil(begin/(step*scale));
  while(ticks[ti]<=(end+(end-begin)*0.00001) && ti<*tick_nr) {
    ti++; ticks[ti]=ticks[0]+step*scale*(double)ti;
  }
  *tick_nr=ti;
 
  if(verbose>1) {
    printf("   final tick_nr := %d\n", *tick_nr);
    printf("    ticks: %.10E", ticks[0]);
    for(ti=1; ti<*tick_nr; ti++) printf(", %.10E", ticks[ti]);
    printf("\n");
  }
 
  /* Quit, if user did not like scales etc */
  if(scale_factor==NULL && tick_decimals==NULL) return(0);
 
  /* Calculate step scale */
  double step_scale=log10(scale);
  if(verbose>1) printf("  step_scale=%g\n", step_scale);
 
  /* Find the highest tick label */
  double tick_high;
  int tick_scale, scale_dif;
  if(fabs(ticks[0])>fabs(ticks[*tick_nr-1])) tick_high=ticks[0];
  else tick_high=ticks[*tick_nr-1];
  if(verbose>1) printf("  tick_high := %.10E\n", tick_high);
  tick_scale=0;
  while(fabs(tick_high)<1.0) {tick_high*=10.0; tick_scale--;}
  while(fabs(tick_high)>=10.0) {tick_high/=10.0; tick_scale++;}
  if(verbose>1) printf("  scaled_tick_high := %g\n  tick_scale := %d\n", tick_high, tick_scale);
 
  /* Calculate the difference between tick and step scales */
  scale_dif=tick_scale-step_scale;
  if(verbose>1) printf("  scale_dif := %d\n", scale_dif);
  /* That determines the tick number precision */
  if(tick_decimals!=NULL) {
    *tick_decimals=1+scale_dif;
    if(verbose>1) printf("  tick_decimals := %d\n", *tick_decimals);
  }
 
  /* Calculate the preferred tick scale factor, or quit, if it is not needed */
  if(scale_factor==NULL) return(0);
  *scale_factor=tick_scale;
  if(verbose>1) printf("  scale_factor := %g\n", *scale_factor);
 
  return(0);
}
/*****************************************************************************/
 
/*****************************************************************************/
void axis_check_range(
  double *begin,
  double *end,
  int verbose
) {
  double temp;
 
  if(verbose>0) printf("axis_check_range(%g, %g, %d)\n", *begin, *end, verbose);
 
  if(*begin<*end) {
    // fine now
  } else if(*begin>*end) {
    temp=*end; *end=*begin; *begin=temp;
  } else { // this means that begin==end
    if(*begin==0.0) {
      *begin=-1.0; *end=1.0;
    } else if(*begin<0.0) {
      *begin*=2.0; *end=0.0;
    } else {
      *begin=0.0; *end*=2.0;
    }
    if(verbose>2) {
      printf("  new begin := %g\n", *begin);
      printf("  new end := %g\n", *end);
    }
    return;
  }
  /* If range is very small */
  if((*end-*begin)<1.0e-98) {
    if(*begin>=1.0e-98 || *begin<0.0) *begin-=1.0e-98;
    else if(*begin>=0.0) *begin=0.0;
    if(*end<=-1.0e-98 || *end>0.0) *end+=1.0e-98;
    else if(*end<0.0) *end=0.0;
    if(verbose>2) {
      printf("   new begin := %g\n", *begin);
      printf("   new end := %g\n", *end);
    }
    return;
  }
  /* If range is relatively large */
  if(*begin>0.0 && *end>0.0) {
    if((*end-*begin)>3.3*(*begin)) *begin=0.0;
  } else if(*begin<0.0 && *end<0.0) {
    if((*end-*begin)>3.3*(-*end)) *end=0.0;
  }
  /* If data range is relatively small (compared to level) */
  temp=(*end-*begin)*2.0/(fabs(*end)+fabs(*begin));
  if(temp<0.01) {
    temp=0.5*(*end-*begin)*0.01/temp;
    if(*begin<0.0 || *begin>temp) *begin-=temp; else *begin=0.0;
    if(*end>0.0 || *end<-temp) *end+=temp; else *end=0.0;
  }
 
  return;
}
/*****************************************************************************/
 
/*****************************************************************************/
void strRmExpZeroes(char *str)
{
  char *p, *r;
  int i, n;
  
  if(str==NULL || strlen(str)<3) return;
  // search the exp E
  p=strrchr(str, 'E'); if(p==NULL) p=strrchr(str, 'e'); if(p==NULL) return;
  // if only +,- and 0 after it, then remove also E
  r=p+1; if(strspn(r, "0+-")==strlen(r)) {*p=(char)0; return;}
  // remove next '+' or jump over '-'
  p++;
  if(*p=='+') {r=p; while(1) {*r=*(r+1); if(*r==(char)0) break; r++;}}
  else if(*p=='-') p++;
  // count initial zeroes
  n=strspn(p, "0"); if(n==0) return;
  // copy the rest of the string over zeroes
  r=p+n; n=strlen(r);
  for(i=0; i<=n; i++) {*p=*r; p++; r++;}
  return;
}
/*****************************************************************************/
 
/*****************************************************************************/