rasterwindow.cpp Example File

rasterwindow/rasterwindow.cpp
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#include "rasterwindow.h" RasterWindow::RasterWindow(QWindow *parent) : QWindow(parent) , m_backingStore(new QBackingStore(this)) { setGeometry(100, 100, 300, 200); } bool RasterWindow::event(QEvent *event) { if (event->type() == QEvent::UpdateRequest) { renderNow(); return true; } return QWindow::event(event); } void RasterWindow::renderLater() { requestUpdate(); } void RasterWindow::resizeEvent(QResizeEvent *resizeEvent) { m_backingStore->resize(resizeEvent->size()); } void RasterWindow::exposeEvent(QExposeEvent *) { if (isExposed()) renderNow(); } 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); } void RasterWindow::render(QPainter *painter) { painter->drawText(QRectF(0, 0, width(), height()), Qt::AlignCenter, QStringLiteral("QWindow")); }