Qml Axes#

This is a demonstration of how to use axes in your QML application.

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.

Using Axes in Qt Quick Applications#

We begin with a chart that has a line series and a scatter series with random data. Both series use the same axes.

../_images/examples_qmlaxes1.png
ChartView {
    title: "Two Series, Common Axes"
    anchors.fill: parent
    legend.visible: false
    antialiasing: true

    ValueAxis {
        id: axisX
        min: 0
        max: 10
        tickCount: 5
    }

    ValueAxis {
        id: axisY
        min: -0.5
        max: 1.5
    }

    LineSeries {
        id: series1
        axisX: axisX
        axisY: axisY
    }

    ScatterSeries {
        id: series2
        axisX: axisX
        axisY: axisY
    }
}

// Add data dynamically to the series
Component.onCompleted: {
    for (var i = 0; i <= 10; i++) {
        series1.append(i, Math.random());
        series2.append(i, Math.random());
    }
}

The next example shows a chart with some accurate historical data that makes us to use a DateTimeAxis .

../_images/examples_qmlaxes2.png
ChartView {
    title: "Accurate Historical Data"
    anchors.fill: parent
    legend.visible: false
    antialiasing: true

    LineSeries {
        axisX: DateTimeAxis {
            format: "yyyy MMM"
            tickCount: 5
        }
        axisY: ValueAxis {
            min: 0
            max: 150
        }

        // Please note that month in JavaScript months are zero based, so 2 means March
        XYPoint { x: toMsecsSinceEpoch(new Date(1950, 2, 15)); y: 5 }
        XYPoint { x: toMsecsSinceEpoch(new Date(1970, 0, 1)); y: 50 }
        XYPoint { x: toMsecsSinceEpoch(new Date(1987, 12, 31)); y: 102 }
        XYPoint { x: toMsecsSinceEpoch(new Date(1998, 7, 1)); y: 100 }
        XYPoint { x: toMsecsSinceEpoch(new Date(2012, 8, 2)); y: 110 }
    }
}

// DateTimeAxis is based on QDateTimes so we must convert our JavaScript dates to
// milliseconds since epoch to make them match the DateTimeAxis values
function toMsecsSinceEpoch(date) {
    var msecs = date.getTime();
    return msecs;
}

And the final example with a chart that uses a CategoryAxis to make the data easier to understand.

../_images/examples_qmlaxes3.png
ChartView {
    title: "Numerical Data for Dummies"
    anchors.fill: parent
    legend.visible: false
    antialiasing: true

    LineSeries {
        axisY: CategoryAxis {
            min: 0
            max: 30
            CategoryRange {
                label: "critical"
                endValue: 2
            }
            CategoryRange {
                label: "low"
                endValue: 4
            }
            CategoryRange {
                label: "normal"
                endValue: 7
            }
            CategoryRange {
                label: "high"
                endValue: 15
            }
            CategoryRange {
                label: "extremely high"
                endValue: 30
            }
        }

        XYPoint { x: 0; y: 4.3 }
        XYPoint { x: 1; y: 4.1 }
        XYPoint { x: 2; y: 4.7 }
        XYPoint { x: 3; y: 3.9 }
        XYPoint { x: 4; y: 5.2 }
    }
}

Example project @ code.qt.io