adding plotmarkers for two different axises scales

[cooper]

Hi,

I created a plot which got two y-axises in different scale. as you see in the picture:



I have added a marker y=0.5 referring to yLeft axis.

QwtPlotMarker *markerX = new QwtPlotMarker();
    markerX->setLabelAlignment(Qt::AlignRight|Qt::AlignTop);
    markerX->setLineStyle(QwtPlotMarker::HLine);
    markerX->setLinePen(Qt::DotLine);
    markerX->setYValue(0.5);
    markerX->attach(ui->qwtPlot);

QwtPlotMarker *markerX = new QwtPlotMarker();
    markerX->setLabelAlignment(Qt::AlignRight|Qt::AlignTop);
    markerX->setLineStyle(QwtPlotMarker::HLine);
    markerX->setLinePen(Qt::DotLine);
    markerX->setYValue(0.5);
    markerX->attach(ui->qwtPlot);

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Now, I want to add a second marker y=50 referring to yRight axis.

can anyone give me a hint, please?
Thanks in advance.

[Uwe]

marker->setYAxis(QwtPlotItem::yRight);

Uwe

[cooper]

Hi Uwe,

Thanks for your reply.
I got an error message after I edited my program

error: ‘yRight’ is not a member of ‘QwtPlotItem’

Here is my code:

QwtPlotMarker *markerX = new QwtPlotMarker();
    markerX->setLabelAlignment(Qt::AlignRight|Qt::AlignTop);
    markerX->setLineStyle(QwtPlotMarker::HLine);
    markerX->setLinePen(Qt::DotLine);
    markerX->setYValue(50);
    markerX->setYAxis(QwtPlotItem::yRight);
    markerX->attach(ui->qwtPlot);

QwtPlotMarker *markerX = new QwtPlotMarker();
    markerX->setLabelAlignment(Qt::AlignRight|Qt::AlignTop);
    markerX->setLineStyle(QwtPlotMarker::HLine);
    markerX->setLinePen(Qt::DotLine);
    markerX->setYValue(50);
    markerX->setYAxis(QwtPlotItem::yRight);
    markerX->attach(ui->qwtPlot);

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I am using qwt-5.2.1.
I read the following documentation:
http://qwt.sourceforge.net/class_qwt_plot_marker.html

It looks like QwtPlotMarker class does not have a "setYAxis" member.

Can you tell where does the "setYAxis" come from, please?

Thanks again

[davey]

use QwtPlot::yRight instead of QwtPlotItem::yRight.

QwtPlotMarker does not have setYAxis(), but its parent QwtPlotItem has.
http://qwt.sourceforge.net/class_qwt...25d5ae8f01db9a

[cooper]

Thanks "davey". solved it : )