QML内阴影效果(QML Inner Shadow effect)

 我想用QML创建一个内部阴影的矩形，类似于Photoshop作用： 
 
 
 QML有InnerShadow但我无法达到这个效果。 我得到的最接近的是这个 
 
import QtQuick 2.0
import QtGraphicalEffects 1.0

Item {
    id: root
    width: 300
    height: 300

    Rectangle {
        id: myRectangle
        anchors.centerIn: parent
        width: 100
        height: 100
        color: "grey"
    }

    InnerShadow {
        anchors.fill: root
        cached: true
        horizontalOffset: 0
        verticalOffset: 0
        radius: 16
        samples: 32
        color: "#b0000000"
        smooth: true
        source: root
    }
}
 
 这是我从这篇文章得到的一个想法。 但是这个例子只有在root大小比myRectangle ，我不想这样做。 我需要例如200x10正方形，其中阴影均匀地分布在矩形的边缘上。 我为InnerShadow属性尝试了各种值，但我无法接近我想要的效果。 
 
 这可以使用QML实现吗？ 

I want to create a rectangle with inner shadow in QML, something similar with what Photoshop does:
 
 
QML has InnerShadow but I'm unable to achieve this effect. The closest I got was this
 
import QtQuick 2.0
import QtGraphicalEffects 1.0

Item {
    id: root
    width: 300
    height: 300

    Rectangle {
        id: myRectangle
        anchors.centerIn: parent
        width: 100
        height: 100
        color: "grey"
    }

    InnerShadow {
        anchors.fill: root
        cached: true
        horizontalOffset: 0
        verticalOffset: 0
        radius: 16
        samples: 32
        color: "#b0000000"
        smooth: true
        source: root
    }
}
 
which is an idea I got from this post. However this example only works if root has a significantly bigger size than myRectangle and I don't want that. I need e.g. a 200x10 square in which shadow is uniformly spread across the edges of the rectangle. I tried all kinds of values for the InnerShadow properties but I couldn't get even close to the effect I want.
 
Can this be achieved using QML?

原文：https://stackoverflow.com/questions/29517596