SplineChart Example#
The example shows how to create a simple spline chart.
Running the Example#
To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example.
Creating Spline Charts#
To create spline charts we need to put our data into QSplineSeries . QSplineSeries automatically calculates spline segment control points that are needed to properly draw the spline.
series = QSplineSeries() series.setName("spline")
Now let’s add some data points to the series.
series.append(0, 6) series.append(2, 4) series.append(3, 8) series.append(7, 4) series.append(10, 5) series << QPointF(11, 1) << QPointF(13, 3) << QPointF(17, 6) << QPointF(18, 3) << QPointF(20, 2)
The data series has been populated. To display it on a chart we create a QChart object and add the data series to it. We also set the title and the values range on the y-axis, so that our chart’s visibility is better.
chart = QChart() chart.legend().hide() chart.addSeries(series) chart.setTitle("Simple spline chart example") chart.createDefaultAxes() chart.axes(Qt.Vertical).first().setRange(0, 10)
Then we create a QChartView object with QChart as a parameter. This way we don’t need to create a QGraphicsView scene ourselves. We also set the Antialiasing on to have the rendered lines look nicer.
chartView = QChartView(chart) chartView.setRenderHint(QPainter.Antialiasing)
Finally, we set the QChartView as the windows’s central widget.
window = QMainWindow() window.setCentralWidget(chartView) window.resize(400, 300) window.show()