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 和 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();
        }
    }
					

范例工程 @ code.qt.io