Problem with scale ticks

[gd]

Hi all,

I want to display a plot with a fixed number of major and minor ticks and I don't want to display for each major tick the corresponding label.

This is my code:

void Form1::init()
{
 
    qwtPlot1->setCanvasBackground(Qt::blue);
    QwtPlotGrid *grid=new QwtPlotGrid();
    grid->setPen(QPen(Qt::white,0,DotLine));
    grid->attach(qwtPlot1);
 
 
    QwtValueList xytick[QwtScaleDiv::NTickTypes];
    for (int i=0;i<11;i++)
        xytick[QwtScaleDiv::MajorTick]<<i/10.0;
    for (int i=0;i<61;i++)
        xytick[QwtScaleDiv::MinorTick]<<i/60.0;
 
 
    qwtPlot1->enableAxis(QwtPlot::xTop,true);
    qwtPlot1->enableAxis(QwtPlot::yRight,true);
 
 
    qwtPlot1->setAxisScaleDiv(QwtPlot::xBottom,QwtScaleDiv(0.0,1.0,xytick));
    qwtPlot1->setAxisScaleDiv(QwtPlot::xTop,QwtScaleDiv(0.0,1.0,xytick));
    qwtPlot1->setAxisScaleDiv(QwtPlot::yLeft,QwtScaleDiv(0.0,1.0,xytick));
    qwtPlot1->setAxisScaleDiv(QwtPlot::yRight,QwtScaleDiv(0.0,1.0,xytick));
 
    qwtPlot1->setAxisScaleDraw(QwtPlot::xBottom,new NullScaleDraw());
    qwtPlot1->setAxisScaleDraw(QwtPlot::xTop,new NullScaleDraw());
    qwtPlot1->setAxisScaleDraw(QwtPlot::yLeft,new NullScaleDraw());
    qwtPlot1->setAxisScaleDraw(QwtPlot::yRight,new NullScaleDraw());
}

void Form1::init()
{

    qwtPlot1->setCanvasBackground(Qt::blue);
    QwtPlotGrid *grid=new QwtPlotGrid();
    grid->setPen(QPen(Qt::white,0,DotLine));
    grid->attach(qwtPlot1);


    QwtValueList xytick[QwtScaleDiv::NTickTypes];
    for (int i=0;i<11;i++)
        xytick[QwtScaleDiv::MajorTick]<<i/10.0;
    for (int i=0;i<61;i++)
        xytick[QwtScaleDiv::MinorTick]<<i/60.0;


    qwtPlot1->enableAxis(QwtPlot::xTop,true);
    qwtPlot1->enableAxis(QwtPlot::yRight,true);


    qwtPlot1->setAxisScaleDiv(QwtPlot::xBottom,QwtScaleDiv(0.0,1.0,xytick));
    qwtPlot1->setAxisScaleDiv(QwtPlot::xTop,QwtScaleDiv(0.0,1.0,xytick));
    qwtPlot1->setAxisScaleDiv(QwtPlot::yLeft,QwtScaleDiv(0.0,1.0,xytick));
    qwtPlot1->setAxisScaleDiv(QwtPlot::yRight,QwtScaleDiv(0.0,1.0,xytick));

    qwtPlot1->setAxisScaleDraw(QwtPlot::xBottom,new NullScaleDraw());
    qwtPlot1->setAxisScaleDraw(QwtPlot::xTop,new NullScaleDraw());
    qwtPlot1->setAxisScaleDraw(QwtPlot::yLeft,new NullScaleDraw());
    qwtPlot1->setAxisScaleDraw(QwtPlot::yRight,new NullScaleDraw());
}

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and

class NullScaleDraw: public QwtScaleDraw
{
public:
  NullScaleDraw()
  {
  }
  virtual QwtText label(double v) const
  {
      return QString("");
  }
};

class NullScaleDraw: public QwtScaleDraw
{
public:
  NullScaleDraw()
  {
  }
  virtual QwtText label(double v) const
  {
      return QString("");
  }
};

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This gives me the output displayed in the attached file qwtplot.jpg.

My question is why the last major ticks of both xBottom and xTop and the first major ticks of both yLeft and yRight axis disappear when I call qwtPlot1->setAxisScaleDraw(...,new NullScaleDraw)?

Is it possible to avoid the displaying of the tick labels in an easier way?

Thanks a lot for you help.

Best regards