app.qml

//![0]
import Charts 1.0
import QtQuick 2.0

Item {
    width: 300; height: 200

    PieChart {
        id: chart
        anchors.centerIn: parent
        width: 100; height: 100

        pieSlice: PieSlice {
            anchors.fill: parent
            color: "red"
        }
    }

    Component.onCompleted: console.log("The pie is colored " + chart.pieSlice.color)
}
//![0]

customPropertyTypes.py

"""PySide6 port of the qml/tutorials/extending-qml/chapter4-customPropertyTypes example from Qt v5.x"""

import os
import sys

from PySide6.QtCore import Property, QUrl
from PySide6.QtGui import QGuiApplication, QPen, QPainter, QColor
from PySide6.QtQml import qmlRegisterType
from PySide6.QtQuick import QQuickPaintedItem, QQuickView, QQuickItem

class PieSlice (QQuickPaintedItem):

    def __init__(self, parent = None):
        QQuickPaintedItem.__init__(self, parent)
        self._color = QColor()

    def getColor(self):
        return self._color

    def setColor(self, value):
        self._color = value

    color = Property(QColor, getColor, setColor)

    def paint(self, painter):
        pen = QPen(self._color, 2)
        painter.setPen(pen)
        painter.setRenderHints(QPainter.Antialiasing, True)
        painter.drawPie(self.boundingRect().adjusted(1,1,-1,-1), 90 * 16, 290 * 16)

class PieChart (QQuickItem):
    def __init__(self, parent = None):
        QQuickItem.__init__(self, parent)
        self._name = None
        self._pieSlice = None

    def getName(self):
        return self._name

    def setName(self, value):
        self._name = value

    name = Property(str, getName, setName)

    def getPieSlice(self):
        return self._pieSlice

    def setPieSlice(self, value):
        self._pieSlice = value
        self._pieSlice.setParentItem(self)

    pieSlice = Property(PieSlice, getPieSlice, setPieSlice)

if __name__ == '__main__':
    app = QGuiApplication(sys.argv)

    qmlRegisterType(PieChart, 'Charts', 1, 0, 'PieChart')
    qmlRegisterType(PieSlice, "Charts", 1, 0, "PieSlice")

    view = QQuickView()
    view.setResizeMode(QQuickView.SizeRootObjectToView)
    qmlFile = os.path.join(os.path.dirname(__file__), 'app.qml')
    view.setSource(QUrl.fromLocalFile(os.path.abspath(qmlFile)))
    if view.status() == QQuickView.Error:
        sys.exit(-1)
    view.show()
    res = app.exec_()
    # Deleting the view before it goes out of scope is required to make sure all child QML instances
    # are destroyed in the correct order.
    del view
    sys.exit(res)