To draw a graph with real time input using QTWidgets for Technical(QWT)



  • hi,

    I am very new to this topic. I am installed QWT from Ubuntu software centre. In .ui file I drag n drop the QwtPlot widget and I selected the slot as

    bq. void qwt::on_qwtPlot_legendChecked(QwtPlotItem *plotItem, bool on)

    then I run the code, It giving an error QwtPlotItem is not declared. then I am try to include "#include <qwt_plot.h>" but it is also giving same error. What is my problem I am not getting anything.
    If I want to include src n lib file of qwt-6.1.0 in qwt.pro file but I am not having this files because I am Installed directly from Ubuntu software centre. Where can I have this folders ?
    please reply me It's urgent
    Can any one guide me



  • In my .pro file I am including the path of the qwt so it will run with out any errors but after compilation it displaying

    bq. QMetaObject::connectSlotsByName: No matching signal for on_qwtPlot_legendChecked(QwtPlotItem*,bool)

    Why I am getting this one and how can I take the real values and plot that values in graph?

    please any body help me



  • please any body help me from this problem--



  • No one have the idea about this?


  • Moderators

    I can give two advises.
    Firstly a bit more patience you have started the thread 8 hours ago.
    Secondly a bit more information to give others a chance to help.

    I recap:
    You use ubuntu and installed stuff included in this distro. At least you should tell which version.
    You use Qt of some version.
    You use QWT of unknown version, but it is not compatible with QWT version 6.1.0.



  • Actually they gave me this yesterday only and they want today itself so I post 3times. my ubuntu version is 12.04 and qt is 2.7.1 and qwt is 6.1.0.


  • Moderators

    You are trying to use the automatic connect by slot name. The slot does not satisfy the rules.
    If you like to connect to the checked signal it is more likely "on_qwtPlot_legend_checked" instead of "on_qwtPlot_legendChecked". Note: the name of your instance I cannot check.


  • Moderators

    "Here is the proper description":http://qt-project.org/doc/qt-4.8/qmetaobject.html#connectSlotsByName form the documentation a bit hidden away :-(



  • I have to check this one,

    Sir is there any possible to use only libraries to draw a graph? Is it required qwt widgets?

    If it is please explain me.

    and I have main question is my data is coming from a background C program. this data will be used to draw plot sir to show the changes in data


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