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 {
		http.Error(w, "Could not execute dot; may need to install graphviz.",

		Total:       rpt.total,
	}
	return g, c
}

// printDOT prints an annotated callgraph in DOT format.
func printDOT(w io.Writer, rpt *Report) error {
	g, c := GetDOT(rpt)
	graph.ComposeDot(w, g, &graph.DotAttributes{}, c)
	return nil
}

// ProfileLabels returns printable labels for a profile.
func ProfileLabels(rpt *Report) []string {
	label := []string{}
	prof := rpt.prof