Rendering SVG inside QTableView

[krzysieklfc]

Hi,

I want to render animated SVG inside QTableView cell.

Basically something like this:

void TableViewDelegate::paint(QPainter* painter, const QStyleOptionViewItem& option,
const QModelIndex& index) const
{
	if (index.column() == 0) {
		if (condition) {
			auto svg = QSvgWidget();
			svg.load(QString{ ":/res/img/spinning_icon.svg" });
			svg.setBaseSize(QSize{ 28, 28 });
			svg.setAutoFillBackground(false);
			m_view->setIndexWidget(index, &svg);
		}
	}
	
	QStyledItemDelegate::paint(painter, option, index);
}

But this solution creates multiple widgets, and I only need one SVG instance so the animation is nicely synchronized.
Also QWidget::setAutoFillBackground(false) doesn't change the background transparency and the widgets are stretched.

I'm sure there's a better way of doing this.

[mrjj]

Hi
What about QSvgRenderer `?
It allows to paint to random Painter.
https://doc.qt.io/qt-5/qsvgrenderer.html#render
So you could have it as member of the delegate and use it to render
to the rows.
However, im not sure that works better in term of synchronization.

[JonB]

@krzysieklfc said in Rendering SVG inside QTableView:

But this solution creates multiple widgets

You are doing this for a whole column.

[krzysieklfc]

@mrjj I wasn't sure which API is the way to go, but I did the following and it works perfectly. Thanks!

	TableViewDelegate::TableViewDelegate(TableView* view, QObject* parent)
		: QStyledItemDelegate(parent), m_view(view)
	{
		svg_renderer = new QSvgRenderer(QString{ ":/res/img/spinning_icon.svg" }, m_view);

		connect(svg_renderer, &QSvgRenderer::repaintNeeded,
			[this] {
			m_view->viewport()->update();
		});
	}


	void TableViewDelegate::paint(QPainter* painter, const QStyleOptionViewItem& option,
		const QModelIndex& index) const
	{
		QStyleOptionViewItem opt{ option };
		initStyleOption(&opt, index);

		if (index.column() == 0) {
			if (condition)
			{
				// transform rect, otherwise renders in whole cell
				auto bounds = opt.rect;
				bounds.setWidth(28);
				bounds.moveTo(opt.rect.center().x() - bounds.width() / 2,
					opt.rect.center().y() - bounds.height() / 2);

				svg_renderer->render(painter, bounds);
				QStyledItemDelegate::paint(painter, opt, index);
			}
		}
	}

	TableView::TableView(QWidget* parent) : QTableView(parent)
	{
		m_delegate = new TableViewDelegate(this);
		setItemDelegate(m_delegate);
	}