QtQuick 2.x Canvas textBaseline middle isn't working

import QtQuick 2.0

Rectangle {
    id: root
    width: 800
    height: 600

    Canvas {
        id: canvas
        anchors.fill: parent

        onPaint: {
            var ctx = canvas.getContext("2d");
            if (ctx === null) {
                console.log("ctx = null");
            }
            ctx.clearRect(0, 0, canvas.width, canvas.height);
            ctx.textBaseline = "middle";
            ctx.fillText("Hello Word", mouseArea.mouseX, mouseArea.mouseY);
            ctx.fill();
        }

        MouseArea {
            id: mouseArea
            anchors.fill: parent
            hoverEnabled: true
            onClicked: canvas.requestPaint();
        }
    }
}