// Copyright (C) 2016 The Qt Company Ltd. // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause #include class MyWidget : public QWidget { public: MyWidget(); protected: void paintEvent(QPaintEvent *); }; MyWidget::MyWidget() { QPalette palette(MyWidget::palette()); palette.setColor(backgroundRole(), Qt::white); setPalette(palette); } void MyWidget::paintEvent(QPaintEvent *) { QPainter painter(this); painter.setRenderHint(QPainter::Antialiasing); painter.setPen(Qt::darkGreen); painter.drawRect(1, 2, 6, 4); //painter.setPen(Qt::darkGray); //painter.drawLine(2, 8, 6, 2); } int main(int argc, char *argv[]) { QApplication app(argc, argv); MyWidget widget; widget.show(); return app.exec(); }