QCharts automatic axes scaling problem

SebastianH

Dear all,

I want to plot data with QCharts. My idea is to create a chart and series in the constructor and add the series to the chart. Then I'd like like to add data to the series in a function and add axes to the chart that are scaled to the data points.

createDefaultAxes() seems to do just what I want, but the scaling only works if I add the series to the chart after adding the data points.

My code looks like so:

    QLineSeries *series = new QLineSeries();
    QChart *chart = new QChart();
    chart->setTitle("Simple line chart example");
    ui->chartView->setChart(chart);
    ui->chartView->setRenderHint(QPainter::Antialiasing);

    chart->addSeries(series); // <- axes _not_ scaled properly

    series->append(0, 0);
    series->append(2, 4);
    series->append(3, 8);
    series->append(7, 4);
    series->append(10, 5);

    // chart->addSeries(series); // <- axes scaled properly

    chart->createDefaultAxes();

I don't really understand why it makes a difference, where series is added to chart. In the end, it's just a pointer, right?

Does anyone have an idea how I can tell chart that its series has updated?

Any help is appreciated :-)

Best,
Sebastian

SebastianH

Can anyone just confirm that it at least should work? Or am I reading the documentation wrong? Otherwise I'd file a bug...

Best,
Sebastian

SGaist

Hi,

From a quick look at the documentation, I haven't see anything stating that adding points to a series after it has been added to a chart should trigger anything. The QAstractSeries class also doesn't seem to offer anything related to triggering an update.