PySide6-examples: QML Plugins examples

- example that can be easily visualized using pyside6-qml tool

Task-number: PYSIDE-1878
Change-Id: Ibf909bbd9efa586ed05318c6b6402ff00a33848e
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

7 files changed, 148 insertions, 0 deletions

diff --git a/examples/declarative/extending/chapter6-plugins/Charts/piechart.py b/examples/declarative/extending/chapter6-plugins/Charts/piechart.py
new file mode 100644
index 000000000..b721a7130
--- /dev/null
+++ b/examples/declarative/extending/chapter6-plugins/Charts/piechart.py
@@ -0,0 +1,40 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+from PySide6.QtCore import Property
+from PySide6.QtQml import QmlElement, ListProperty
+from PySide6.QtQuick import QQuickItem
+
+from pieslice import PieSlice
+
+# To be used on the @QmlElement decorator
+# (QML_IMPORT_MINOR_VERSION is optional)
+QML_IMPORT_NAME = "Charts"
+QML_IMPORT_MAJOR_VERSION = 1
+
+@QmlElement
+class PieChart(QQuickItem):
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        self._slices = []
+        self._name = ''
+
+    @Property(str)
+    def name(self):
+        return self._name
+
+    @name.setter
+    def name(self, name):
+        self._name = name
+
+    def slice(self, n):
+        return self._slices[n]
+
+    def sliceCount(self):
+        return len(self._slices)
+
+    def append_and_setparent(self, slice):
+        self._slices.append(slice)
+        slice.setParentItem(self)
+
+    slices = ListProperty(PieSlice, append_and_setparent)
diff --git a/examples/declarative/extending/chapter6-plugins/Charts/pieslice.py b/examples/declarative/extending/chapter6-plugins/Charts/pieslice.py
new file mode 100644
index 000000000..7945eff12
--- /dev/null
+++ b/examples/declarative/extending/chapter6-plugins/Charts/pieslice.py
@@ -0,0 +1,52 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+from PySide6.QtCore import Property, QRectF
+from PySide6.QtGui import QColor, QPainter, QPen
+from PySide6.QtQuick import QQuickPaintedItem
+from PySide6.QtQml import QmlElement
+
+# To be used on the @QmlElement decorator
+# (QML_IMPORT_MINOR_VERSION is optional)
+QML_IMPORT_NAME = "Charts"
+QML_IMPORT_MAJOR_VERSION = 1
+
+@QmlElement
+class PieSlice(QQuickPaintedItem):
+    def __init__(self, parent=None):
+        super().__init__(parent)
+
+        self._color = QColor()
+        self._from_angle = 0
+        self._angle_span = 0
+
+    @Property(QColor)
+    def color(self):
+        return self._color
+
+    @color.setter
+    def color(self, color):
+        self._color = QColor(color)
+
+    @Property(int)
+    def fromAngle(self):
+        return self._from_angle
+
+    @fromAngle.setter
+    def fromAngle(self, fromAngle):
+        self._from_angle = fromAngle
+
+    @Property(int)
+    def angleSpan(self):
+        return self._angle_span
+
+    @angleSpan.setter
+    def angleSpan(self, angleSpan):
+        self._angle_span = angleSpan
+
+    def paint(self, painter):
+        painter.setPen(QPen(self._color, 2))
+        painter.setRenderHint(QPainter.RenderHint.Antialiasing, True)
+
+        rect = QRectF(0, 0, self.width(), self.height()).adjusted(1, 1, -1, -1)
+        painter.drawPie(rect, self._from_angle * 16, self._angle_span * 16)
diff --git a/examples/declarative/extending/chapter6-plugins/Charts/plugins.png b/examples/declarative/extending/chapter6-plugins/Charts/plugins.png
new file mode 100644
index 000000000..8992e89c0
--- /dev/null
+++ b/examples/declarative/extending/chapter6-plugins/Charts/plugins.png
diff --git a/examples/declarative/extending/chapter6-plugins/app.qml b/examples/declarative/extending/chapter6-plugins/app.qml
new file mode 100644
index 000000000..70761619f
--- /dev/null
+++ b/examples/declarative/extending/chapter6-plugins/app.qml
@@ -0,0 +1,32 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+import QtQuick 2.0
+import Charts 1.0
+
+Item {
+    width: 300; height: 200
+
+    PieChart {
+        anchors.centerIn: parent
+        width: 100; height: 100
+
+        slices: [
+            PieSlice {
+                anchors.fill: parent
+                color: "red"
+                fromAngle: 0; angleSpan: 110
+            },
+            PieSlice {
+                anchors.fill: parent
+                color: "black"
+                fromAngle: 110; angleSpan: 50
+            },
+            PieSlice {
+                anchors.fill: parent
+                color: "blue"
+                fromAngle: 160; angleSpan: 100
+            }
+        ]
+    }
+}
diff --git a/examples/declarative/extending/chapter6-plugins/chapter6-plugins.pyproject b/examples/declarative/extending/chapter6-plugins/chapter6-plugins.pyproject
new file mode 100644
index 000000000..8f6121b0c
--- /dev/null
+++ b/examples/declarative/extending/chapter6-plugins/chapter6-plugins.pyproject
@@ -0,0 +1,3 @@
+{
+    "files": ["app.qml", "/Charts/piechart.py", "/Charts/pieslice.py"]
+}
diff --git a/examples/declarative/extending/chapter6-plugins/doc/chapter6-plugins.rst b/examples/declarative/extending/chapter6-plugins/doc/chapter6-plugins.rst
new file mode 100644
index 000000000..10aba1e8f
--- /dev/null
+++ b/examples/declarative/extending/chapter6-plugins/doc/chapter6-plugins.rst
@@ -0,0 +1,21 @@
+.. _qml-chapter6-plugins-example:
+
+Extending QML - Plugins Example
+===============================
+
+This example refers to the Python version of using a QML plugin in Python. The idea of plugins in
+Python is non-existent because Python modules are dynamically loaded anyway. We use this idea and
+our QML type registration decorators - QmlELement/QmlNamedElement - to register the QML modules as
+they are imported. The pyside6-qml tool does this for you by simply pointing to the .qml file.
+
+.. image:: plugins.png
+   :width: 400
+   :alt: Plugins Example
+
+
+Running the Example
+-------------------
+
+.. code-block:: shell
+
+    pyside6-pyqml examples/declarative/extending/chapter6-plugins/app.qml -I examples/declarative/extending/chapter6-plugins/Charts
diff --git a/examples/declarative/extending/chapter6-plugins/doc/plugins.png b/examples/declarative/extending/chapter6-plugins/doc/plugins.png
new file mode 100644
index 000000000..8992e89c0
--- /dev/null
+++ b/examples/declarative/extending/chapter6-plugins/doc/plugins.png