#!/usr/bin/env python
 
 
#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
##
## "Redistribution and use in source and binary forms, with or without
## modification, are permitted provided that the following conditions are
## met:
##   * Redistributions of source code must retain the above copyright
##     notice, this list of conditions and the following disclaimer.
##   * Redistributions in binary form must reproduce the above copyright
##     notice, this list of conditions and the following disclaimer in
##     the documentation and/or other materials provided with the
##     distribution.
##   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
##     the names of its contributors may be used to endorse or promote
##     products derived from this software without specific prior written
##     permission.
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## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
## $QT_END_LICENSE$
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#############################################################################
 
 
from PyQt5.QtCore import QRect, QRectF, QSize, Qt, QTimer
from PyQt5.QtGui import QColor, QPainter, QPalette, QPen
from PyQt5.QtWidgets import (QApplication, QFrame, QGridLayout, QLabel,
        QSizePolicy, QWidget)
 
 
class CircleWidget(QWidget):
    def __init__(self, parent=None):
        super(CircleWidget, self).__init__(parent)
 
        self.floatBased = False
        self.antialiased = False
        self.frameNo = 0
 
        self.setBackgroundRole(QPalette.Base)
        self.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
 
    def setFloatBased(self, floatBased):
        self.floatBased = floatBased
        self.update()
 
    def setAntialiased(self, antialiased):
        self.antialiased = antialiased
        self.update()
 
    def minimumSizeHint(self):
        return QSize(50, 50)
 
    def sizeHint(self):
        return QSize(180, 180)
 
    def nextAnimationFrame(self):
        self.frameNo += 1
        self.update()
 
    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing, self.antialiased)
        painter.translate(self.width() / 2, self.height() / 2)
 
        for diameter in range(0, 256, 9):
            delta = abs((self.frameNo % 128) - diameter / 2)
            alpha = 255 - (delta * delta) / 4 - diameter
            if alpha > 0:
                painter.setPen(QPen(QColor(0, diameter / 2, 127, alpha), 3))
 
                if self.floatBased:
                    painter.drawEllipse(QRectF(-diameter / 2.0,
                            -diameter / 2.0, diameter, diameter))
                else:
                    painter.drawEllipse(QRect(-diameter / 2,
                            -diameter / 2, diameter, diameter))
 
 
class Window(QWidget):
    def __init__(self):
        super(Window, self).__init__()
 
        aliasedLabel = self.createLabel("Aliased")
        antialiasedLabel = self.createLabel("Antialiased")
        intLabel = self.createLabel("Int")
        floatLabel = self.createLabel("Float")
 
        layout = QGridLayout()
        layout.addWidget(aliasedLabel, 0, 1)
        layout.addWidget(antialiasedLabel, 0, 2)
        layout.addWidget(intLabel, 1, 0)
        layout.addWidget(floatLabel, 2, 0)
 
        timer = QTimer(self)
 
        for i in range(2):
            for j in range(2):
                w = CircleWidget()
                w.setAntialiased(j != 0)
                w.setFloatBased(i != 0)
 
                timer.timeout.connect(w.nextAnimationFrame)
 
                layout.addWidget(w, i + 1, j + 1)
 
        timer.start(100)
        self.setLayout(layout)
 
        self.setWindowTitle("Concentric Circles")
 
    def createLabel(self, text):
        label = QLabel(text)
        label.setAlignment(Qt.AlignCenter)
        label.setMargin(2)
        label.setFrameStyle(QFrame.Box | QFrame.Sunken)
        return label
 
 
if __name__ == '__main__':
 
    import sys
 
    app = QApplication(sys.argv)
    window = Window()
    window.show()
    sys.exit(app.exec_())