// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#ifndef RASTERWINDOW_H
#define RASTERWINDOW_H
//! [1]
#include <QtGui>
#include <QScopedPointer>
class RasterWindow : public QWindow
{
Q_OBJECT
public:
explicit RasterWindow(QWindow *parent = nullptr);
virtual void render(QPainter *painter);
public slots:
void renderLater();
void renderNow();
protected:
bool event(QEvent *event) override;
void resizeEvent(QResizeEvent *event) override;
void exposeEvent(QExposeEvent *event) override;
private:
QScopedPointer<QBackingStore> m_backingStore;
};
//! [1]
#endif // RASTERWINDOW_H
// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "rasterwindow.h"
//! [1]
RasterWindow::RasterWindow(QWindow *parent)
: QWindow(parent)
, m_backingStore(new QBackingStore(this))
{
setGeometry(100, 100, 300, 200);
}
//! [1]
//! [7]
bool RasterWindow::event(QEvent *event)
{
if (event->type() == QEvent::UpdateRequest) {
renderNow();
return true;
}
return QWindow::event(event);
}
//! [7]
//! [6]
void RasterWindow::renderLater()
{
requestUpdate();
}
//! [6]
//! [5]
void RasterWindow::resizeEvent(QResizeEvent *resizeEvent)
{
m_backingStore->resize(resizeEvent->size());
}
//! [5]
//! [2]
void RasterWindow::exposeEvent(QExposeEvent *)
{
if (isExposed())
renderNow();
}
//! [2]
//! [3]
void RasterWindow::renderNow()
{
if (!isExposed())
return;
QRect rect(0, 0, width(), height());
m_backingStore->beginPaint(rect);
QPaintDevice *device = m_backingStore->paintDevice();
QPainter painter(device);
painter.fillRect(0, 0, width(), height(), QGradient::NightFade);
render(&painter);
painter.end();
m_backingStore->endPaint();
m_backingStore->flush(rect);
}
//! [3]
//! [4]
void RasterWindow::render(QPainter *painter)
{
painter->drawText(QRectF(0, 0, width(), height()), Qt::AlignCenter, QStringLiteral("QWindow"));
}
//! [4]
