axis.c File Reference

Axis for XY plots. More...

#include "libtpcsvg.h"

Go to the source code of this file.

Functions
int	axis_tick_positions (const double begin, const double end, double *ticks, int *tick_nr, double *scale_factor, int *tick_decimals, int verbose)
void	axis_check_range (double *begin, double *end, int verbose)
void	strRmExpZeroes (char *str)

Detailed Description

Axis for XY plots.

Author

Vesa Oikonen

Definition in file axis.c.

Function Documentation

axis_check_range()

void axis_check_range	(	double *	begin,
		double *	end,
		int	verbose )

Check and if necessary correct axis range: min must be smaller than max. Also, if the range is close to zero, then make it larger. Also, if the range is relatively large, then change it to start from zero.

See also

axis_tick_positions, svg_calculate_axes

Parameters

begin	axis range minimum
end	axis range maximum
verbose	Verbose level; if zero, then nothing is printed to stderr or stdout

Definition at line 116 of file axis.c.

  {
  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;
}

Referenced by svg_calculate_axes().

axis_tick_positions()

int axis_tick_positions	(	const double	begin,
		const double	end,
		double *	ticks,
		int *	tick_nr,
		double *	scale_factor,
		int *	tick_decimals,
		int	verbose )

Define suitable tick positions for XY plot.

Returns

Returns 0 if successful, <>0 in case of error.

See also

axis_check_range, svg_calculate_axes

Parameters

begin	axis range minimum.
end	axis range maximum.
ticks	Pointer to array where tick values will be written. Length must be at least tick_nr.
tick_nr	Input: Max allowed nr of ticks; Output: actual nr of ticks.
scale_factor	Output: Suggested scale factor (x10^sf). NULL, if not needed.
tick_decimals	Output: tick value precision (nr of decimals). NULL, if not needed.
verbose	Verbose level; if zero, then nothing is printed to stderr or stdout.

Definition at line 14 of file axis.c.

  {
  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);
}

Referenced by svg_calculate_axes().

strRmExpZeroes()

void strRmExpZeroes

(

char *

str

)

Remove initial exponential zeroes from the exponential part of string representation of values, for example, '1.01E-010' -> '1.01E-10'.

Definition at line 179 of file axis.c.

{
  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;
}

Referenced by svg_calculate_axes().