Autosizing the pixel size of text based on text length or size using fontSizeMode

I am trying to use fontSizeMode in order to fix a large text in a rectangle.

import QtQuick 2.9import QtQuick.Window 2.2Window{    visible: true    width: 640    height: 480    title: qsTr("Hello World")    Rectangle    {        color: "Red"        height:50        width:50        Text        {            text: "Hello"            fontSizeMode: Text.Fit            minimumPixelSize: 5            font.pixelSize: 50         }    }}

My aim is to shrink the text size if the text is bigger than the rectangle, and a minimum pixel size is given as shown in the program. But the text is not shrinking.

How can I solve this problem?