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Subclassing WAbstractTableModel for WCartesianChart

Added by Neel Basu about 8 years ago

I have a Chart Model that subclasses from WAbstractTableModel

ChartModel::ChartModel(unsigned int history, Wt::WObject* parent):Wt::WAbstractTableModel(parent), _history(history){

}
int ChartModel::columnCount(const Wt::WModelIndex& parent) const{
    if(parent.isValid())
        return 0;
    std::cout << "columnCount" << std::endl;
    return 2;
}
int ChartModel::rowCount(const Wt::WModelIndex& parent) const{
    if(parent.isValid())
        return 0;
    std::cout << "rowCount" << " " << parent.row() << " " << parent.column() << " " << _history << std::endl;
    return _history;
}
boost::any ChartModel::data(const Wt::WModelIndex& index, int role) const{
    std::cout << "data: " << index.row() << " " << index.column() << " " << role << std::endl;
    switch(role){
        case Wt::DisplayRole:
        case Wt::ToolTipRole:{
            pair_type point = _elements.at(index.row());
            if(index.column() == 0) return point.first;
            else                                        return point.second;
        }
        default:
            return boost::any();
    }   
}

When I run this application I see nothing on the chart, only rowCount() is called repeatedly with ModelIndex(0,0) but columnCount is not being called at all.


Replies (2)

RE: Subclassing WAbstractTableModel for WCartesianChart - Added by Neel Basu about 8 years ago

This is how I am passing the model to WCartesianChart

    chart = new Wt::Chart::WCartesianChart(Wt::Chart::ChartType::ScatterPlot, parent);
    model = new ChartModel(history, chart);
    series = new Wt::Chart::WDataSeries(1, Wt::Chart::SeriesType::LineSeries);
    chart->addSeries(*series);
    series->bindToAxis(Wt::Chart::Axis::YAxis);
    series->setModelColumn(1);
    chart->setRubberBandEffectEnabled(false);   
    chart->resize(600, 200);

    chart->setStyleClass("col-sm-6 chart");
    chart->setTitle(name);
    chart->setTextPen(Wt::WColor(255, 255, 255));
    chart->setModel(model);
    chart->setXSeriesColumn(0);
    chart->setType(Wt::Chart::ScatterPlot);     
    chart->setBackground(Wt::WColor(0, 0, 0));
    chart->axis(Wt::Chart::Axis::XAxis).setScale(Wt::Chart::DateTimeScale);
    chart->axis(Wt::Chart::Axis::XAxis).setPen(Wt::WColor(255, 255, 255));
    chart->axis(Wt::Chart::Axis::YAxis).setPen(Wt::WColor(255, 255, 255));

    for(int i = 0; i < history; i++){
        model->append(1);
    }

RE: Subclassing WAbstractTableModel for WCartesianChart - Added by Aaron Wright about 8 years ago

For both rowCount() and columnCount() you return 0 when the index is valid. Isn't that logic backwards?

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