Method paintEvent

src/3rdparty/Qt-Advanced-Docking-System/src/FloatingDragPreview.cpp:454–485

============================================================================

//============================================================================
void CFloatingDragPreview::paintEvent(QPaintEvent* event)
{
	Q_UNUSED(event);
	if (d->Hidden)
	{
		return;
	}

	QPainter painter(this);
	painter.setOpacity(0.6);
	if (CDockManager::testConfigFlag(CDockManager::DragPreviewShowsContentPixmap))
	{
		painter.drawPixmap(QPoint(0, 0), d->ContentPreviewPixmap);
	}

	// If we do not have a window frame then we paint a QRubberBand like
	// frameless window
	if (!CDockManager::testConfigFlag(CDockManager::DragPreviewHasWindowFrame))
	{
		QColor Color = palette().color(QPalette::Active, QPalette::Highlight);
		QPen Pen = painter.pen();
		Pen.setColor(Color.darker(120));
		Pen.setStyle(Qt::SolidLine);
		Pen.setWidth(1);
		Pen.setCosmetic(true);
		painter.setPen(Pen);
		Color = Color.lighter(130);
		Color.setAlpha(64);
		painter.setBrush(Color);
		painter.drawRect(rect().adjusted(0, 0, -1, -1));
	}
}

//============================================================================
void CFloatingDragPreview::onApplicationStateChanged(Qt::ApplicationState state)