Method add_vline

src/plot_widget.rs:239–242

Add a vertical reference line to the plot. If there exists a line with the same `vline.id` ([ShapeId]), the old one will be replaced.

(&mut self, vline: VLine)

    ) -> Result<(), SeriesError> {
        if let Some(series) = self.series.get_mut(id) {
            f(series);
            self.data_version += 1;
            Ok(())
        } else {
            Err(SeriesError::NotFound(*id))
        }
    }