}
	if rx != nil && matched == 0 {
		return fmt.Errorf("no matches found for regexp: %s", rx)
	}
	return nil
}

// GetDOT returns a graph suitable for dot processing along with some
// configuration information.
func GetDOT(rpt *Report) (*graph.Graph, *graph.DotConfig) {
	g, origCount, droppedNodes, droppedEdges := rpt.newTrimmedGraph()
	rpt.selectOutputUnit(g)

	rpt, errList := ui.makeReport(w, req, []string{"svg"}, nil)
	if rpt == nil {
		return // error already reported
	}

	// Generate dot graph.
	g, config := report.GetDOT(rpt)
	legend := config.Labels
	config.Labels = nil
	dot := &bytes.Buffer{}
	graph.ComposeDot(dot, g, &graph.DotAttributes{}, config)

	// Convert to svg.
	svg, err := dotToSvg(dot.Bytes())
	if err != nil {