关于qt：如何在QML Shapes上启用抗锯齿？

How do I enable antialiasing on QML Shapes?

这是一个具有Dial控件和自定义形状并排的QML文件：

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import QtQuick 2.9
import QtQuick.Layouts 1.3
import QtQuick.Controls 2.3
import QtQuick.Window 2.2
import QtQuick.Shapes 1.0

Window {
id: window
visible: true
width: 400
height: 200

RowLayout {
anchors.horizontalCenter: parent.horizontalCenter
anchors.verticalCenter: parent.verticalCenter
spacing: 5

Dial {
id: dial1
}

Control {
id: dial2

implicitWidth: dial1.width
implicitHeight: dial1.height

antialiasing: true

Shape {
anchors.fill: parent

antialiasing: true

ShapePath {
strokeWidth: 1
strokeColor: dial2.visualFocus ? dial2.palette.highlight : dial2.palette.dark

startX: dial2.width/2
startY: 0

PathArc {
x: dial2.width/2
y: dial2.height
radiusX: dial2.width/2
radiusY: dial2.height/2
direction: PathArc.Clockwise
}

PathArc {
x: dial2.width/2
y: 0
radiusX: dial2.width/2
radiusY: dial2.height/2
direction: PathArc.Clockwise
}

}
}
}
}
}

由于在控件和图形上均设置了antialiasing: true，所以我希望路径看起来很平滑。但是，它看起来参差不齐：

Dial

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int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);

QSurfaceFormat format;
format.setSamples(8);
QSurfaceFormat::setDefaultFormat(format);

QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
if (engine.rootObjects().isEmpty())
return -1;

return app.exec();
}

或者，如果您希望将此设置限制为单个QtQuick层，则还可以设置以下样本数量：

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import QtQuick 2.8
import QtQuick.Window 2.2
import QtQuick.Shapes 1.0

Window {
visible: true
width: 640
height: 480

Item {
id: root
anchors.fill: parent
layer.enabled: true
layer.samples: 4
// your shapes here ...
}
}

将其设置在图层上似乎对Shape的vendorExtensionsEnabled: true无效，这是默认设置。将其设置为false似乎可以使用。