QwtPolarPlot radius scale

[brutus35]

Hello,
I'm looking for how to create my own major and minor ticks on the scaleId
QwtPolar::Radius.
I tried :

if (!d_prefDlg->get_pasZ_Auto()) {
         /* Récupération du pas choisi
         ****************************/
         double pasz = d_prefDlg->get_pasZ();
 
         /* Ajustement des extrema
         ************************/
         nivmax = pasz*ceil(nivmax/pasz);
         nivmin = pasz*floor(nivmin/pasz);
 
         /* Nombre de pas
         ***************/
         double nbPas = ((int)(((nivmax-nivmin)/pasz)));
 
         /* Recherche du meilleur pas principal
         *************************************/
         double major;
         for(int ii=8; ii>1; ii--) {
                 major = floor(nbPas/ii);
                 if (major > 5)
                         break;
         }
         double pasMajor = major*pasz;
         int nbPasminor = floor(pasMajor/pasz);
         d_polarplot->setScale(QwtPolar::Radius,nivmin, nivmax, pasMajor);
         d_polarplot->setScaleMaxMajor(QwtPolar::Radius, major);
         d_polarplot->setScaleMaxMinor(QwtPolar::Radius, nbPasminor);
 
 
         /* Création des pas principaux et secondaires
         ********************************************/
         QList<double> ticksR[QwtScaleDiv::NTickTypes];
         QList<double> &majorTicksR = ticksR[QwtScaleDiv::MajorTick];
         QList<double> &minorTicksR = ticksR[QwtScaleDiv::MinorTick];
         for (double niveau=nivmin; niveau <= nivmax; niveau=niveau+pasz) {
             if (fmod((niveau-nivmin),major*pasz) == 0) {
                 majorTicksR.append(niveau);
             } else {
                 minorTicksR.append(niveau);
             }
         }
 
         QwtScaleDiv myScaleDivR = QwtScaleDiv(majorTicksR.first(),
 majorTicksR.last(), ticksR);
         d_polarplot->setScaleDiv(QwtPolar::Radius, myScaleDivR);
         if (d_polarplot->scaleDiv(QwtPolar::Radius)->isValid() == false)
             Message("Invalide", false);
 
         } else
             d_polarplot->setScale(QwtPolar::Radius,nivmin, nivmax);

if (!d_prefDlg->get_pasZ_Auto()) {
         /* Récupération du pas choisi
         ****************************/
         double pasz = d_prefDlg->get_pasZ();
 
         /* Ajustement des extrema
         ************************/
         nivmax = pasz*ceil(nivmax/pasz);
         nivmin = pasz*floor(nivmin/pasz);
 
         /* Nombre de pas
         ***************/
         double nbPas = ((int)(((nivmax-nivmin)/pasz)));
 
         /* Recherche du meilleur pas principal
         *************************************/
         double major;
         for(int ii=8; ii>1; ii--) {
                 major = floor(nbPas/ii);
                 if (major > 5)
                         break;
         }
         double pasMajor = major*pasz;
         int nbPasminor = floor(pasMajor/pasz);
         d_polarplot->setScale(QwtPolar::Radius,nivmin, nivmax, pasMajor);
         d_polarplot->setScaleMaxMajor(QwtPolar::Radius, major);
         d_polarplot->setScaleMaxMinor(QwtPolar::Radius, nbPasminor);
 
 
         /* Création des pas principaux et secondaires
         ********************************************/
         QList<double> ticksR[QwtScaleDiv::NTickTypes];
         QList<double> &majorTicksR = ticksR[QwtScaleDiv::MajorTick];
         QList<double> &minorTicksR = ticksR[QwtScaleDiv::MinorTick];
         for (double niveau=nivmin; niveau <= nivmax; niveau=niveau+pasz) {
             if (fmod((niveau-nivmin),major*pasz) == 0) {
                 majorTicksR.append(niveau);
             } else {
                 minorTicksR.append(niveau);
             }
         }
 
         QwtScaleDiv myScaleDivR = QwtScaleDiv(majorTicksR.first(),
 majorTicksR.last(), ticksR);
         d_polarplot->setScaleDiv(QwtPolar::Radius, myScaleDivR);
         if (d_polarplot->scaleDiv(QwtPolar::Radius)->isValid() == false)
             Message("Invalide", false);
 
         } else
             d_polarplot->setScale(QwtPolar::Radius,nivmin, nivmax);

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With nivmin = -93, nivmax=-39 and pasz=3, I should get the following major
ticks :-93,-75,-57 and -39, with 6 minor ticks between 2 major ticks.

But that did'nt work (see attach file).

Thanks for your help