Example of having rounded image corners in Qt6 (Alternative to Qt5's OpacityMask)

roundedImage.qml

import QtQuick
import QtQuick.Effects

Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    Image {
        id: sourceItem
        source: "https://fastly.picsum.photos/id/727/300/300.jpg?hmac=kPiO13OlbcnHcQFJ0pIJpQhUZYUMz358Vvt0P-voCO4"
        anchors.centerIn: parent
        width: 300
        height: 300
        visible: false
    }

    MultiEffect {
        source: sourceItem
        anchors.fill: sourceItem
        maskEnabled: true
        maskSource: mask
        maskThresholdMin: 0.5
        maskSpreadAtMin: 1.0
    }

    Item {
        id: mask
        width: sourceItem.width
        height: sourceItem.height
        layer.enabled: true
        visible: false
        layer.smooth: true

        Rectangle {
            width: sourceItem.width
            height: sourceItem.height
            radius: 20
            color: "black"
        }
    }
}