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# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
"""PySide6 port of the Qt Quick customgeometry example from Qt v6.x"""
import sys
from pathlib import Path
from PySide6.QtQuick import (QQuickView, QQuickItem, QSGNode, QSGGeometryNode,
QSGGeometry, QSGFlatColorMaterial)
from PySide6.QtQml import QmlElement
from PySide6.QtGui import QGuiApplication, QColor
from PySide6.QtCore import (QPointF, QUrl, Property, Signal, Slot)
# To be used on the @QmlElement decorator
# (QML_IMPORT_MINOR_VERSION is optional)
QML_IMPORT_NAME = "CustomGeometry"
QML_IMPORT_MAJOR_VERSION = 1
@QmlElement
class BezierCurve(QQuickItem):
p1Changed = Signal()
p2Changed = Signal()
p3Changed = Signal()
p4Changed = Signal()
segmentCountChanged = Signal()
def __init__(self, parent=None):
super().__init__(parent)
self._p1 = QPointF(0, 0)
self._p2 = QPointF(1, 0)
self._p3 = QPointF(0, 1)
self._p4 = QPointF(1, 1)
self._segmentCount = 32
self._node = None
self._geometry = None
self.setFlag(QQuickItem.Flags.ItemHasContents, True)
def p1(self):
return self._p1
def p2(self):
return self._p2
def p3(self):
return self._p3
def p4(self):
return self._p4
def segmentCount(self):
return self._segmentCount
@Slot(QPointF)
def setP1(self, p):
if p != self._p1:
self._p1 = p
self.p1Changed.emit()
self.update()
@Slot(QPointF)
def setP2(self, p):
if p != self._p2:
self._p2 = p
self.p2Changed.emit()
self.update()
@Slot(QPointF)
def setP3(self, p):
if p != self._p3:
self._p3 = p
self.p3Changed.emit()
self.update()
@Slot(QPointF)
def setP4(self, p):
if p != self._p4:
self._p4 = p
self.p4Changed.emit()
self.update()
@Slot(int)
def setSegmentCount(self, p):
if p != self._segmentCount:
self._segmentCount = p
self.segmentCountChanged.emit()
self.update()
def updatePaintNode(self, oldNode, updatePaintNodeData):
self._node = oldNode
if not self._node:
self._default_attributes = QSGGeometry.defaultAttributes_Point2D()
self._geometry = QSGGeometry(self._default_attributes, self._segmentCount)
self._geometry.setLineWidth(2)
self._geometry.setDrawingMode(QSGGeometry.DrawingMode.DrawLineStrip)
self._node = QSGGeometryNode()
self._node.setGeometry(self._geometry)
self._node.setFlag(QSGNode.Flags.OwnsGeometry)
self._material = QSGFlatColorMaterial()
self._material.setColor(QColor(255, 0, 0))
self._node.setMaterial(self._material)
self._node.setFlag(QSGNode.Flags.OwnsMaterial)
else:
self._geometry = self._node.geometry()
self._geometry.allocate(self._segmentCount)
item_size = self.size()
item_width = float(item_size.width())
item_height = float(item_size.height())
vertices = self._geometry.vertexDataAsPoint2D()
for i in range(self._segmentCount):
t = float(i) / float(self._segmentCount - 1)
inv_t = 1 - t
pos = ((inv_t * inv_t * inv_t * self._p1)
+ (3 * inv_t * inv_t * t * self._p2)
+ (3 * inv_t * t * t * self._p3)
+ (t * t * t * self._p4))
vertices[i].set(pos.x() * item_width, pos.y() * item_height)
self._geometry.setVertexDataAsPoint2D(vertices)
self._node.markDirty(QSGNode.DirtyGeometry)
return self._node
p1 = Property(QPointF, p1, setP1, notify=p1Changed)
p2 = Property(QPointF, p2, setP2, notify=p2Changed)
p3 = Property(QPointF, p3, setP3, notify=p3Changed)
p4 = Property(QPointF, p4, setP4, notify=p4Changed)
segmentCount = Property(int, segmentCount, setSegmentCount,
notify=segmentCountChanged)
if __name__ == "__main__":
app = QGuiApplication([])
view = QQuickView()
format = view.format()
format.setSamples(16)
view.setFormat(format)
qml_file = Path(__file__).parent / "main.qml"
view.setSource(QUrl.fromLocalFile(qml_file))
if not view.rootObject():
sys.exit(-1)
view.show()
ex = app.exec()
del view
sys.exit(ex)
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