1#!/usr/bin/env python
2
3
4#############################################################################
5##
6## Copyright (C) 2013 Riverbank Computing Limited.
7## Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
8##
9## This file is part of the examples of PyQt.
10##
11## $QT_BEGIN_LICENSE:BSD$
12## You may use this file under the terms of the BSD license as follows:
13##
14## "Redistribution and use in source and binary forms, with or without
15## modification, are permitted provided that the following conditions are
16## met:
17##   * Redistributions of source code must retain the above copyright
18##     notice, this list of conditions and the following disclaimer.
19##   * Redistributions in binary form must reproduce the above copyright
20##     notice, this list of conditions and the following disclaimer in
21##     the documentation and/or other materials provided with the
22##     distribution.
23##   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
24##     of its contributors may be used to endorse or promote products derived
25##     from this software without specific prior written permission.
26##
27##
28## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
39## $QT_END_LICENSE$
40##
41#############################################################################
42
43
44from PyQt5.QtCore import pyqtProperty, pyqtSignal, QPointF, QUrl
45from PyQt5.QtGui import QColor, QGuiApplication
46from PyQt5.QtQml import qmlRegisterType
47from PyQt5.QtQuick import (QQuickItem, QQuickView, QSGFlatColorMaterial,
48        QSGGeometry, QSGGeometryNode, QSGNode)
49
50import customgeometry_rc
51
52
53class BezierCurve(QQuickItem):
54
55    p1Changed = pyqtSignal(QPointF)
56
57    @pyqtProperty(QPointF, notify=p1Changed)
58    def p1(self):
59        return self._p1
60
61    @p1.setter
62    def p1(self, p):
63        if self._p1 != p:
64            self._p1 = QPointF(p)
65            self.p1Changed.emit(p)
66            self.update()
67
68    p2Changed = pyqtSignal(QPointF)
69
70    @pyqtProperty(QPointF, notify=p2Changed)
71    def p2(self):
72        return self._p2
73
74    @p2.setter
75    def p2(self, p):
76        if self._p2 != p:
77            self._p2 = QPointF(p)
78            self.p2Changed.emit(p)
79            self.update()
80
81    p3Changed = pyqtSignal(QPointF)
82
83    @pyqtProperty(QPointF, notify=p3Changed)
84    def p3(self):
85        return self._p3
86
87    @p3.setter
88    def p3(self, p):
89        if self._p3 != p:
90            self._p3 = QPointF(p)
91            self.p3Changed.emit(p)
92            self.update()
93
94    p4Changed = pyqtSignal(QPointF)
95
96    @pyqtProperty(QPointF, notify=p4Changed)
97    def p4(self):
98        return self._p4
99
100    @p4.setter
101    def p4(self, p):
102        if self._p4 != p:
103            self._p4 = QPointF(p)
104            self.p4Changed.emit(p)
105            self.update()
106
107    segmentCountChanged = pyqtSignal(int)
108
109    @pyqtProperty(int, notify=segmentCountChanged)
110    def segmentCount(self):
111        return self._segmentCount
112
113    @segmentCount.setter
114    def segmentCount(self, count):
115        if self._segmentCount != count:
116            self._segmentCount = count
117            self.segmentCountChanged.emit(count)
118            self.update()
119
120    def __init__(self, parent=None):
121        super(BezierCurve, self).__init__(parent)
122
123        self._p1 = QPointF(0, 0)
124        self._p2 = QPointF(1, 0)
125        self._p3 = QPointF(0, 1)
126        self._p4 = QPointF(1, 1)
127
128        self._segmentCount = 32
129
130        self._root_node = None
131
132        self.setFlag(QQuickItem.ItemHasContents, True)
133
134    def updatePaintNode(self, oldNode, nodeData):
135        if self._root_node is None:
136            self._root_node = QSGGeometryNode()
137
138            geometry = QSGGeometry(QSGGeometry.defaultAttributes_Point2D(),
139                    self._segmentCount)
140            geometry.setLineWidth(2)
141            geometry.setDrawingMode(QSGGeometry.GL_LINE_STRIP)
142            self._root_node.setGeometry(geometry)
143            self._root_node.setFlag(QSGNode.OwnsGeometry)
144
145            material = QSGFlatColorMaterial()
146            material.setColor(QColor(255, 0, 0))
147            self._root_node.setMaterial(material)
148            self._root_node.setFlag(QSGNode.OwnsMaterial)
149        else:
150            geometry = self._root_node.geometry()
151            geometry.allocate(self._segmentCount)
152
153        w = self.width()
154        h = self.height()
155        vertices = geometry.vertexDataAsPoint2D()
156
157        for i in range(self._segmentCount):
158            t = i / float(self._segmentCount - 1)
159            invt = 1 - t
160
161            pos = invt * invt * invt * self._p1 \
162                    + 3 * invt * invt * t * self._p2 \
163                    + 3 * invt * t * t * self._p3 \
164                    + t * t * t * self._p4
165
166            vertices[i].set(pos.x() * w, pos.y() * h)
167
168        self._root_node.markDirty(QSGNode.DirtyGeometry)
169
170        return self._root_node
171
172
173if __name__ == '__main__':
174    import sys
175
176    app = QGuiApplication(sys.argv)
177
178    qmlRegisterType(BezierCurve, "CustomGeometry", 1, 0, "BezierCurve")
179
180    view = QQuickView()
181    format = view.format()
182    format.setSamples(16)
183    view.setFormat(format)
184
185    view.setSource(QUrl('qrc:///scenegraph/customgeometry/main.qml'))
186    view.show()
187
188    sys.exit(app.exec_())
189