axislayout.h

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#ifndef axislayout_h
#define axislayout_h

/*+
________________________________________________________________________

 (C) dGB Beheer B.V.; (LICENSE) http://opendtect.org/OpendTect_license.txt
 Author:        A.H.Bril
 Date:          Jan 2005 / Dec 2009
 RCS:           $Id$
________________________________________________________________________

-*/

#include "algomod.h"
#include "ranges.h"
#include "samplingdata.h"

#include <math.h>


template <class T>
mClass(Algo) AxisLayout
{
public:
                        // Have layout calculated
                        AxisLayout( const Interval<T>& dr, bool asint=false,
                                    bool inside=false )
                            : annotinint_(asint)
                            , annotinsiderg_(inside)
                        { setDataRange( dr ); }

    void                setDataRange(const Interval<T>&);
    StepInterval<T>     getSampling() const;

    SamplingData<T>     sd_;
    T                   stop_;
    bool                annotinint_;
    bool                annotinsiderg_;

                        // Init with explicit layout
                        AxisLayout( T start=0, T st_op=1,
                                    T step=1 )
                            : sd_(start,step), stop_(st_op)
                            , annotinsiderg_(false)
                            , annotinint_(false)        {}

                        AxisLayout( const StepInterval<T>& rg )
                            : sd_(rg.start,rg.step)
                            , stop_(rg.stop)
                            , annotinsiderg_(false)
                            , annotinint_(false)    {}

                        // Returns 'modulo' end with this sd_ and stop_
    T                   findEnd(T datastop) const;
};


template <class T> inline
StepInterval<T> AxisLayout<T>::getSampling() const
{ return StepInterval<T>( sd_.start, stop_, sd_.step ); }


template <class T> inline
void AxisLayout<T>::setDataRange( const Interval<T>& dr )
{
    Interval<T> intv = dr;
    sd_.start = intv.start;
    const bool rev = intv.start > intv.stop;
    if ( rev ) Swap( intv.start, intv.stop );
    T wdth = intv.width();


    // guard against zero interval
    T indic = intv.start + wdth;
    T indic_start = intv.start;
    if ( mIsZero(indic,mDefEps) ) { indic_start += 1; indic += 1; }
    indic = 1 - indic_start / indic;
    if ( mIsZero(indic,mDefEps) )
    {
        sd_.start = intv.start - 1;
        sd_.step = 1;
        stop_ = intv.start + 1;
        return;
    }

    double scwdth = wdth < 1e-30 ? -30 : log10( (double)wdth );
    int tenpow = 1 - (int)scwdth; if ( scwdth < 0 ) tenpow++;
    double stepfac = Math::IntPowerOf( ((double)10), tenpow );
    scwdth = wdth * stepfac;

    double scstep;
    if ( scwdth < 15 )          scstep = annotinint_ ? 2. : 2.5;
    else if ( scwdth < 30 )     scstep = 5;
    else if ( scwdth < 50 )     scstep = 10;
    else                        scstep = 20;

    sd_.step = (T) ( scstep / stepfac );
    if ( annotinint_ )
    {
        int istep = mNINT32( sd_.step );
        if ( istep == 0 )
            istep = 1;
        sd_.step = (T)istep;
    }

    if ( mIsZero(sd_.step,mDefEps) )
        sd_.step = 1;

    if ( wdth > 1e-30 )
    {
        double idx0 = 0;
        if ( annotinsiderg_ )
        {
            idx0 = rev ? Math::Floor(intv.stop / sd_.step + 1e-6)
                       : Math::Ceil(intv.start / sd_.step + 1e-6);
        }
        else
        {
            idx0 = rev ? Math::Ceil(intv.stop / sd_.step + 1e-6)
                       : Math::Floor(intv.start / sd_.step + 1e-6);
        }

        sd_.start = mNINT32( idx0 ) * sd_.step;
    }
    if ( rev ) sd_.step = -sd_.step;

    stop_ = findEnd( rev ? intv.start : intv.stop );
}


template <class T> inline
T AxisLayout<T>::findEnd( T datastop ) const
{
    SamplingData<T> worksd = sd_;
    const bool rev = worksd.step < 0;
    if ( rev )
    {
        worksd.start = -worksd.start;
        worksd.step = -worksd.step;
        datastop = -datastop;
    }

    if ( worksd.start + 10000 * worksd.step < datastop )
        return datastop;

    const double dnrsteps = double(datastop-worksd.start)/worksd.step - 1e-6;
    int nrsteps =
        mNINT32( (annotinsiderg_ ? Math::Floor(dnrsteps)
                                 : Math::Ceil(dnrsteps)) );
    if ( nrsteps < 1 ) nrsteps = 1;
    T wdth = nrsteps * worksd.step;
    return sd_.start + (rev ? -wdth : wdth);
}

#endif