- Qt 6.8
- Qt Charts
- Using Axes with QML
- Qt Charts | Commercial or GPLv3

# Using Axes with QML

Note: This is part of the Charts with QML Gallery example.

We begin with a chart that has a line series and a scatter series with random data. We then have a graph with two series that share a common axis.

     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());
             }
         }
     }

This chart shows some accurate historical data. It is created by the following snippet that makes use of a DateTimeAxis.

     ChartView {
         id: root
         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: root.toMsecsSinceEpoch(new Date(1950, 2, 15)); y: 5 }
             XYPoint { x: root.toMsecsSinceEpoch(new Date(1970, 0, 1)); y: 50 }
             XYPoint { x: root.toMsecsSinceEpoch(new Date(1987, 12, 31)); y: 102 }
             XYPoint { x: root.toMsecsSinceEpoch(new Date(1998, 7, 1)); y: 100 }
             XYPoint { x: root.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;
         }
     }

This following chart is created using 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 }
         }
     }