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# Copyright (C) 2013 Riverbank Computing Limited.
# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
import math
import sys
from PySide6.QtCore import QPointF, QTimer, Qt
from PySide6.QtGui import (QBrush, QColor, QLinearGradient, QPainter, QPen,
QPixmap, QRadialGradient)
from PySide6.QtWidgets import (QApplication, QFrame, QGraphicsDropShadowEffect,
QGraphicsEllipseItem, QGraphicsRectItem,
QGraphicsScene, QGraphicsView, QWidget)
class Lighting(QGraphicsView):
def __init__(self, parent=None):
super().__init__(parent)
self.angle = 0.0
self.m_scene = QGraphicsScene()
self.m_lightSource = None
self.m_items = []
self.setScene(self.m_scene)
self.setup_scene()
timer = QTimer(self)
timer.timeout.connect(self.animate)
timer.setInterval(30)
timer.start()
self.setRenderHint(QPainter.Antialiasing)
self.setFrameStyle(QFrame.NoFrame)
def setup_scene(self):
self.m_scene.setSceneRect(-300, -200, 600, 460)
linear_grad = QLinearGradient(QPointF(-100, -100),
QPointF(100, 100))
linear_grad.setColorAt(0, QColor(255, 255, 255))
linear_grad.setColorAt(1, QColor(192, 192, 255))
self.setBackgroundBrush(linear_grad)
radial_grad = QRadialGradient(30, 30, 30)
radial_grad.setColorAt(0, Qt.yellow)
radial_grad.setColorAt(0.2, Qt.yellow)
radial_grad.setColorAt(1, Qt.transparent)
pixmap = QPixmap(60, 60)
pixmap.fill(Qt.transparent)
with QPainter(pixmap) as painter:
painter.setPen(Qt.NoPen)
painter.setBrush(radial_grad)
painter.drawEllipse(0, 0, 60, 60)
self.m_lightSource = self.m_scene.addPixmap(pixmap)
self.m_lightSource.setZValue(2)
for i in range(-2, 3):
for j in range(-2, 3):
if (i + j) & 1:
item = QGraphicsEllipseItem(0, 0, 50, 50)
else:
item = QGraphicsRectItem(0, 0, 50, 50)
item.setPen(QPen(Qt.black, 1))
item.setBrush(QBrush(Qt.white))
effect = QGraphicsDropShadowEffect(self)
effect.setBlurRadius(8)
item.setGraphicsEffect(effect)
item.setZValue(1)
item.setPos(i * 80, j * 80)
self.m_scene.addItem(item)
self.m_items.append(item)
def animate(self):
self.angle += (math.pi / 30)
xs = 200 * math.sin(self.angle) - 40 + 25
ys = 200 * math.cos(self.angle) - 40 + 25
self.m_lightSource.setPos(xs, ys)
for item in self.m_items:
effect = item.graphicsEffect()
delta = QPointF(item.x() - xs, item.y() - ys)
effect.setOffset(QPointF(delta.toPoint() / 30))
dd = math.hypot(delta.x(), delta.y())
color = effect.color()
color.setAlphaF(max(0.4, min(1 - dd / 200.0, 0.7)))
effect.setColor(color)
self.m_scene.update()
if __name__ == '__main__':
app = QApplication(sys.argv)
lighting = Lighting()
lighting.setWindowTitle("Lighting and Shadows")
lighting.resize(640, 480)
lighting.show()
sys.exit(app.exec())
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