Qt 5.13 | Qt Charts | Qml Axes

Qt Charts | Commercial or GPLv3

# 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 }
          }
      }

Example project @ code.qt.io