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#############################################################################
##
## Copyright (C) 2021 The Qt Company Ltd.
## Contact: https://www.qt.io/licensing/
##
## This file is part of the Qt for Python examples of the Qt Toolkit.
##
## $QT_BEGIN_LICENSE:BSD$
## 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 The Qt Company Ltd nor the names of its
## contributors may be used to endorse or promote products derived
## from this software without specific prior written permission.
##
##
## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
##
## $QT_END_LICENSE$
##
#############################################################################
import math
import sys
from PySide6.QtWidgets import QWidget, QApplication
from PySide6.QtCore import QPoint, QRect, QTimer, Qt, Slot
from PySide6.QtGui import (QColor, QPainter, QPaintEvent, QPen, QPointList,
QTransform)
WIDTH = 680
HEIGHT = 480
class PlotWidget(QWidget):
"""Illustrates the use of opaque containers. QPointList
wraps a C++ QList<QPoint> directly, removing the need to convert
a Python list in each call to QPainter.drawPolyline()."""
def __init__(self, parent=None):
super().__init__(parent)
self._timer = QTimer(self)
self._timer.setInterval(20)
self._timer.timeout.connect(self.shift)
self._points = QPointList()
self._points.reserve(WIDTH)
self._x = 0
self._delta_x = 0.05
self._half_height = HEIGHT / 2
self._factor = 0.8 * self._half_height
for i in range(WIDTH):
self._points.append(QPoint(i, self.next_point()))
self.setFixedSize(WIDTH, HEIGHT)
self._timer.start()
def next_point(self):
result = self._half_height - self._factor * math.sin(self._x)
self._x += self._delta_x
return result
def shift(self):
last_x = self._points[WIDTH - 1].x()
self._points.pop_front()
self._points.append(QPoint(last_x + 1, self.next_point()))
self.update()
def paintEvent(self, event):
painter = QPainter()
painter.begin(self)
rect = QRect(QPoint(0, 0), self.size())
painter.fillRect(rect, Qt.white)
painter.translate(-self._points[0].x(), 0)
painter.drawPolyline(self._points)
painter.end()
if __name__ == "__main__":
app = QApplication(sys.argv)
w = PlotWidget()
w.show()
sys.exit(app.exec())
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