remotelaboratory/lib/tqwtplot3d/src/qwt3d_scale.cpp

#include "qwt3d_scale.h"

using namespace Qwt3D;

Scale::Scale() 
: start_p(0.), stop_p(0.), 
  majorintervals_p(0), minorintervals_p(0),
  mstart_p(0.), mstop_p(0.) 
{
}

/*! The function maps the double value at tic-position idx to a final
representation. The default return value is simply the tic values QString 
representation. Overwrite this function, if you plan to transform the value 
in some way. See e.g. LogScale::ticLabel.
\param idx the current major tic index
\return The QString representation for the value corresponding to a valid index, 
an empty QString else.
*/
QString Scale::ticLabel(unsigned int idx) const
{
  if (idx<majors_p.size())
  {
    return QString::number(majors_p[idx]);
  }
  return QString("");
}

//! Sets start and stop value for the scale;
void Scale::setLimits(double start, double stop) 
{
  if (start < stop)
  {
    start_p = start;
    stop_p = stop;
    return;
  }
  start_p = stop;
  stop_p = start;
}

//! Sets value of first major tic
void Scale::setMajorLimits(double start, double stop) 
{
  if (start < stop)
  {
    mstart_p = start;
    mstop_p = stop;
    return;
  }
  mstart_p = stop;
  mstop_p = start;
} 

/*!
  \param a First major tic after applying autoscaling
  \param b Last major tic after applying autoscaling
  \param start Scale begin
  \param stop Scale end
  \param ivals Requested number of major intervals
  \return Number of major intervals after autoscaling\n
  
  The default implementation sets a=start, b=stop and returns ivals.
*/
int Scale::autoscale(double& a, double& b, double start, double stop, int ivals)
{
  a = start;
  b = stop;
  return ivals;
}

/***************************
*
* linear scales
*
***************************/


//! Applies LinearAutoScaler::execute()
int LinearScale::autoscale(double& a, double& b, double start, double stop, int ivals)
{
  return autoscaler_p.execute(a, b, start, stop, ivals);
}

//! Creates the major and minor vector for the scale
void LinearScale::calculate()
{		
  majors_p.clear();
	minors_p.clear();
  
  double interval = mstop_p-mstart_p;

	double runningval;
  int i=0;

  // majors

  // first tic
//  if (mstart_p<start_p || mstop_p>stop_p)
//    return;  
    
  majors_p.push_back(mstart_p);
  
  // remaining tics
  for (i = 1; i <= majorintervals_p; ++i) 
	{
		double t = double(i) / majorintervals_p;
		runningval = mstart_p + t * interval;
    if (runningval>stop_p)
      break;
    if (isPracticallyZero(mstart_p, -t*interval)) // prevent rounding errors near 0
      runningval = 0.0;
    majors_p.push_back(runningval);
	}
  majorintervals_p = majors_p.size();
  if (majorintervals_p)
    --majorintervals_p;


	// minors

  if (!majorintervals_p || !minorintervals_p) // no valid interval
  {
    minorintervals_p = 0;
    return;
  }
  
  // start_p      mstart_p
  //  |_____________|_____ _ _ _

  double step = (majors_p[1]-majors_p[0]) / minorintervals_p;
  if (isPracticallyZero(step))
    return;

  runningval = mstart_p-step;
	while (runningval>start_p)
	{
		minors_p.push_back(runningval);								
		runningval -= step;
	}

  //       mstart_p            mstop_p
  //  ________|_____ _ _ _ _ _ ___|__________

  for (i=0; i!=majorintervals_p; ++i)
  {
    runningval = majors_p[i] + step;
    for (int j=0; j!=minorintervals_p; ++j)
    {
		  minors_p.push_back(runningval);								
		  runningval += step;
	  }
  }
  
  //    mstop_p       stop_p
  // _ _ _|_____________|

  runningval = mstop_p + step;
  while (runningval<stop_p)
  {
	  minors_p.push_back(runningval);								
	  runningval += step;
  }
}

void LogScale::setupCounter(double& k, int& step)
{
  switch(minorintervals_p) 
  {
  case 9:
  	k=9;
    step=1;
    break;
  case 5:
    k=8;
    step=2;
  	break;
  case 3:
    k=5;
    step=3;
  	break;
  case 2:
    k=5;
    step=5;
  	break;
  default:
    k=9;
    step=1;
  }
}

/*! Creates major and minor vectors for the scale.
\warning If the interval is too small, the scale becomes empty
or will contain only a single major tic. There is no automatism 
(also not planned for now) for an 'intelligent' guess, what to do. 
Better switch manually to linear to scales in such cases.
*/
void LogScale::calculate()
{
  majors_p.clear();
	minors_p.clear();

  if (start_p < DBL_MIN_10_EXP)
    start_p = DBL_MIN_10_EXP;
  if (stop_p > DBL_MAX_10_EXP)
    stop_p = DBL_MAX_10_EXP;

  double interval = stop_p-start_p;
  if (interval<=0)
    return;
  
  double runningval = floor(start_p);
  while(runningval<=stop_p) 
	{
    if (runningval>=start_p)
      majors_p.push_back(runningval);
    ++runningval;
	}
  majorintervals_p = majors_p.size();
  if (majorintervals_p)
    --majorintervals_p;

  if (majors_p.size()<1) // not even a single major tic
  {
    return;
  }
  
  
  // minors

  // start_p      mstart_p
  //  |_____________|_____ _ _ _

  double k;
  int step;
  setupCounter(k,step);
	runningval = log10(k)+(majors_p[0]-1);
  while (runningval>start_p && k>1)
	{
		minors_p.push_back(runningval);								
    k -=step;
    runningval = log10(k)+(majors_p[0]-1);
	}

  //       mstart_p            mstop_p
  //  ________|_____ _ _ _ _ _ ___|__________

  for (int i=0; i!=majorintervals_p; ++i)
  {
    setupCounter(k,step);
    runningval = log10(k)+(majors_p[i]);
    while (k>1)
	  {
		  minors_p.push_back(runningval);
      k-=step;
      runningval = log10(k)+(majors_p[i]);
	  }
  }

  //    mstop_p       stop_p
  // _ _ _|_____________|

  setupCounter(k,step);
	runningval = log10(k)+(majors_p.back());
  do 
  {
    k-=step; 
    runningval = log10(k)+(majors_p.back());
  } 
  while(runningval>=stop_p);
  while (k>1)
	{
		minors_p.push_back(runningval);								
    k-=step;
    runningval = log10(k)+(majors_p.back());
	}
}

/*!
Sets the minor intervals for the logarithmic scale. Only values of 9,5,3 or 2 
are accepted as arguments. They will produce mantissa sets of {2,3,4,5,6,7,8,9}, 
{2,4,6,8}, {2,5} or {5} respectively.
*/
void LogScale::setMinors(int val)
{
  if ((val == 2) || (val == 3) || (val == 5) || (val == 9))
    minorintervals_p = val;
}

LogScale::LogScale()
{
  minorintervals_p = 9;
}

//! Returns a power of 10 associated to the major value at index idx.
QString LogScale::ticLabel(unsigned int idx) const
{
  if (idx<majors_p.size())
  {
    double val = majors_p[idx];
    return QString::number(pow(double(10), val));
  }
  return QString("");
}