先看一下做的Demo效果：

代码：

import QtQuick 2.3
import QtQuick.Window 2.2
import QtGraphicalEffects 1.0

Window {
    visible: true
    Item {
        width: parent.width
        height: parent.height
        Image {
            id: person
            source: "qrc:/psb.jpg"
            anchors.fill: parent
            visible: false
        }
        Image {
            id: mask
            source: "qrc:/butterfly_transparent.png"
            anchors.fill: parent
            visible: false
        }
        OpacityMask {
            id:om
            anchors.fill: person
            source: person
            maskSource: mask
        }
    }
}