The Problem:
I have a plot with controls for changing the scale (linear vs log) and for changing the min X and the max X values, then replot. But the code only works well on Mac OS, and not in Linux!

I start out with:
Qt Code: 
  1. calibPlot->setAxisScaleEngine(QwtPlot::xBottom, new QwtLinearScaleEngine () );
  2.     calibPlot->replot();
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Then I call the control buttons: using a function: setupGraphControls();
In the function I define the controls, and connect them to corresponding SLOTS:
Qt Code: 
  1. connect( axisXScale, SIGNAL( activated( const QString &)),
  2. this, SLOT(xAxisScaleChange( const QString &) ) );
  3. connect( axisXStart, SIGNAL( textChanged ( const QString & )),
  4. this, SLOT(xAxisScaleMin( const QString & ) ) );
  5. connect( axisXEnd, SIGNAL( textChanged( const QString &)),
  6. this, SLOT(xAxisScaleMax( const QString &) ) );
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The slots are coded as (one example):
Qt Code: 
  1. void CentralPage::xAxisScaleMin( const QString &xMinVal) 
  2. { 
  3.   bool ok; 
  4.   const bool doReplot = calibPlot->autoReplot(); 
  5.   calibPlot->setAxisScale(QwtPlot::xBottom, xMinVal.toInt(&ok,10),axisXEnd->text().toInt(&ok,10) );   
  6.   calibPlot->setAutoReplot( doReplot ); 
  7.   calibPlot->replot(); }
  8.   }
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In the connection statements, should I be using something else in place of "this" ? Has anyone else seen this issue, I use qwt-5.2.0.

Any more elegant ways of doing this?

// Sal Aguinaga
// Northwestern University