Qt 5.13 | Qt Quick Extras | Qt Quick Extras - Dashboard

Qt 5.13.2 Reference Documentation

# Qt Quick Extras - Dashboard

A car dashboard created using several CircularGauge controls.

This example project demonstrates the use of CircularGauge to create a car dashboard.

The ValueSource type generates random data for testing the dashboard. The data is random but there is a logical link between some of them, for example, `kph` and `rpm`.

      Item {
          id: valueSource
          property real kph: 0
          property real rpm: 1
          property real fuel: 0.85
          property string gear: {
              var g;
              if (kph == 0) {
                  return "P";
              }
              if (kph < 30) {
                  return "1";
              }
              if (kph < 50) {
                  return "2";
              }
              if (kph < 80) {
                  return "3";
              }
              if (kph < 120) {
                  return "4";
              }
              if (kph < 160) {
                  return "5";
              }
          }
          property int turnSignal: gear == "P" && !start ? randomDirection() : -1
          property real temperature: 0.6
          property bool start: true

It runs a looping SequentialAnimation that sets the values of the properties over time.

The SequentialAnimation object consists of several ParallelAnimation objects, which in turn consist of two NumberAnimations, one for `kph` and one for `rpm`. Both let the value develop to a certain value over a specified `duration` with the Easing type `Easing.InOutSine`

                  ParallelAnimation {
                      NumberAnimation {
                          target: valueSource
                          property: "kph"
                          easing.type: Easing.InOutSine
                          from: 0
                          to: 30
                          duration: 3000
                      }
                      NumberAnimation {
                          target: valueSource
                          property: "rpm"
                          easing.type: Easing.InOutSine
                          from: 1
                          to: 6.1
                          duration: 3000
                      }
                  }

The flashTimer object switches the turn signals `on` or `off`.

          Timer {
              id: flashTimer
              interval: 500
              running: on
              repeat: true
              onTriggered: flashing = !flashing
          }

The `paintOutlinePath(ctx)` method does the actual painting of the arrow for the turn signal.

          function paintOutlinePath(ctx) {
              ctx.beginPath();
              ctx.moveTo(0, height * 0.5);
              ctx.lineTo(0.6 * width, 0);
              ctx.lineTo(0.6 * width, height * 0.28);
              ctx.lineTo(width, height * 0.28);
              ctx.lineTo(width, height * 0.72);
              ctx.lineTo(0.6 * width, height * 0.72);
              ctx.lineTo(0.6 * width, height);
              ctx.lineTo(0, height * 0.5);
          }

The screen consists of a `foregroundCanvas` and a `backgroundCanvas`. `foregroundCanvas` displays the green turn signal if the `on` and `flashing` booleans are `true`.

          Canvas {
              id: foregroundCanvas
              anchors.fill: parent
              visible: on && flashing

              onPaint: {
                  var ctx = getContext("2d");
                  ctx.reset();

                  paintOutlinePath(ctx);

                  ctx.fillStyle = "green";
                  ctx.fill();
              }
          }

Example project @ code.qt.io