QML Glow Inside a RowLayout - qt

Question

I am using Qt 5.15 Quick 2 QML to create a row of custom buttons in a window. When I have a standalone custom button things appear to work fine, but when I put them in a RowLayout there appears to be severe clipping and artifacting issues.
A minimum reproducible example might look like:
import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Layouts 1.15
import QtQuick.Controls 2.15
Window {
visible: true
width: 640
height: 480
title: qsTr("Hello World")
RowLayout
{
anchors.fill:parent
anchors.margins: 25
Button
{
text: "Click Me"
Layout.fillWidth: true
}
CustomButton
{
text: "That Boy Don't Glow Right"
}
Button
{
x: 100; y:100
text: "Click Me"
Layout.fillWidth: true
}
}
}
with the custom control
import QtQuick 2.0
import QtQuick.Controls 2.15
import QtGraphicalEffects 1.15
Button {
id: control
text: "Click Me"
Glow {
anchors.fill: control
radius: 64
spread: 0
samples: 128
color: "red"
source: control
visible: true
}
}
with example output:
One potential fix is to add change the Glow to
Glow {
anchors.fill: control
width: parent.width
height:parent.height
x:control.x
y:control.y
parent: control.parent
...
But this doesn't seem right. First, it's not obvious to me where parent.width and control.x and control.parent are bound from and what happens in single and multiple nesting. If a CustomButton is placed inside another control with id control, would it rebind the property? And it appears if a RowLayout is placed inside a RowLayout, then it would require parent: control.parent.parent. In my actual code there is some non-trivial positioning to allow margins for a drop shadow, too, and the CustomButton is in another container so the actual code that works is: x:control.x + parent.pad/2 and parent:control.parent.parent.parent which is, frankly, ridiculous and assumes that non-standard fields in the parent are always available.
Is there a better way? Was hoping I could keep the button's ability to glow itself.

Answer 1

According to the docs:
"Note: It is not supported to let the effect include itself, for instance by setting source to the effect's parent."
So it's fortunate that you were able to get your example to work at all. One way to avoid using the parent as a source is to point the Glow object at the Button's background object:
Button {
id: control
Glow {
source: control.background
}
}