1 files changed, 66 insertions, 0 deletions
diff --git a/examples/widgets/painting/plot/plot.py b/examples/widgets/painting/plot/plot.py
new file mode 100644
index 000000000..fd7ff9937
--- /dev/null
+++ b/examples/widgets/painting/plot/plot.py
@@ -0,0 +1,66 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+import math
+import sys
+
+from PySide6.QtWidgets import QWidget, QApplication
+from PySide6.QtCore import QPoint, QRect, QTimer, Qt
+from PySide6.QtGui import QPainter, QPointList
+
+
+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):
+        with QPainter(self) as painter:
+            rect = QRect(QPoint(0, 0), self.size())
+            painter.fillRect(rect, Qt.white)
+            painter.translate(-self._points[0].x(), 0)
+            painter.drawPolyline(self._points)
+
+
+if __name__ == "__main__":
+
+    app = QApplication(sys.argv)
+
+    w = PlotWidget()
+    w.show()
+    sys.exit(app.exec())