Qt Documentation

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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.

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.

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.

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 }
    }
}

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