1#!/usr/bin/env python
2
3
4#############################################################################
5##
6## Copyright (C) 2013 Riverbank Computing Limited.
7## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
8## All rights reserved.
9##
10## This file is part of the examples of PyQt.
11##
12## $QT_BEGIN_LICENSE:BSD$
13## You may use this file under the terms of the BSD license as follows:
14##
15## "Redistribution and use in source and binary forms, with or without
16## modification, are permitted provided that the following conditions are
17## met:
18##   * Redistributions of source code must retain the above copyright
19##     notice, this list of conditions and the following disclaimer.
20##   * Redistributions in binary form must reproduce the above copyright
21##     notice, this list of conditions and the following disclaimer in
22##     the documentation and/or other materials provided with the
23##     distribution.
24##   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
25##     the names of its contributors may be used to endorse or promote
26##     products derived from this software without specific prior written
27##     permission.
28##
29## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
40## $QT_END_LICENSE$
41##
42#############################################################################
43
44
45import math
46
47from PyQt5.QtCore import QPointF, Qt, QTimer
48from PyQt5.QtGui import (QBrush, QColor, QLinearGradient, QPen, QPainter,
49        QPixmap, QRadialGradient)
50from PyQt5.QtWidgets import (QApplication, QFrame, QGraphicsDropShadowEffect,
51        QGraphicsEllipseItem, QGraphicsRectItem, QGraphicsScene, QGraphicsView)
52
53
54class Lighting(QGraphicsView):
55    def __init__(self, parent=None):
56        super(Lighting, self).__init__(parent)
57
58        self.angle = 0.0
59        self.m_scene = QGraphicsScene()
60        self.m_lightSource = None
61        self.m_items = []
62
63        self.setScene(self.m_scene)
64
65        self.setupScene()
66
67        timer = QTimer(self)
68        timer.timeout.connect(self.animate)
69        timer.setInterval(30)
70        timer.start()
71
72        self.setRenderHint(QPainter.Antialiasing)
73        self.setFrameStyle(QFrame.NoFrame)
74
75    def setupScene(self):
76        self.m_scene.setSceneRect(-300, -200, 600, 460)
77
78        linearGrad = QLinearGradient(QPointF(-100, -100), QPointF(100, 100))
79        linearGrad.setColorAt(0, QColor(255, 255, 255))
80        linearGrad.setColorAt(1, QColor(192, 192, 255))
81        self.setBackgroundBrush(linearGrad)
82
83        radialGrad = QRadialGradient(30, 30, 30)
84        radialGrad.setColorAt(0, Qt.yellow)
85        radialGrad.setColorAt(0.2, Qt.yellow)
86        radialGrad.setColorAt(1, Qt.transparent)
87
88        pixmap = QPixmap(60, 60)
89        pixmap.fill(Qt.transparent)
90
91        painter = QPainter(pixmap)
92        painter.setPen(Qt.NoPen)
93        painter.setBrush(radialGrad)
94        painter.drawEllipse(0, 0, 60, 60)
95        painter.end()
96
97        self.m_lightSource = self.m_scene.addPixmap(pixmap)
98        self.m_lightSource.setZValue(2)
99
100        for i in range(-2, 3):
101            for j in range(-2, 3):
102                if (i + j) & 1:
103                    item = QGraphicsEllipseItem(0, 0, 50, 50)
104                else:
105                    item = QGraphicsRectItem(0, 0, 50, 50)
106
107                item.setPen(QPen(Qt.black, 1))
108                item.setBrush(QBrush(Qt.white))
109
110                effect = QGraphicsDropShadowEffect(self)
111                effect.setBlurRadius(8)
112                item.setGraphicsEffect(effect)
113                item.setZValue(1)
114                item.setPos(i * 80, j * 80)
115                self.m_scene.addItem(item)
116                self.m_items.append(item)
117
118    def animate(self):
119        self.angle += (math.pi / 30)
120        xs = 200 * math.sin(self.angle) - 40 + 25
121        ys = 200 * math.cos(self.angle) - 40 + 25
122        self.m_lightSource.setPos(xs, ys)
123
124        for item in self.m_items:
125            effect = item.graphicsEffect()
126
127            delta = QPointF(item.x() - xs, item.y() - ys)
128            effect.setOffset(QPointF(delta.toPoint() / 30))
129
130            dd = math.hypot(delta.x(), delta.y())
131            color = effect.color()
132            color.setAlphaF(max(0.4, min(1 - dd / 200.0, 0.7)))
133            effect.setColor(color)
134
135        self.m_scene.update()
136
137
138if __name__ == '__main__':
139
140    import sys
141
142    app = QApplication(sys.argv)
143
144    lighting = Lighting()
145    lighting.setWindowTitle("Lighting and Shadows")
146    lighting.resize(640, 480)
147    lighting.show()
148
149    sys.exit(app.exec_())
150