JoystickViewer.qml Example File

quickGamepad/qml/JoystickViewer.qml
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 import QtQuick 2.0

 Item {
     width: 100
     height: 100

     property real xAxisValue: 0
     property real yAxisValue: 0

     onXAxisValueChanged: {
         joystickCanvas.requestPaint();
     }
     onYAxisValueChanged: {
         joystickCanvas.requestPaint()
     }

     Canvas {
         id: joystickCanvas
         anchors.fill: parent

         onPaint: {
             var context = joystickCanvas.getContext("2d")
             context.clearRect(0, 0, width, height);
             var targetX = (xAxisValue + 1) / 2 * width;
             var targetY = (yAxisValue + 1) / 2 * height;
             context.fillStyle = "red";
             context.beginPath();
             context.arc(targetX, targetY, 5, 0, 2 * Math.PI, false);
             context.closePath();
             context.fill();
         }
     }

 }