// Layout runs the dot program to layout the graph.
// If format is "" uses dot format, else specify an output renderer, e.g. "svg".
// The Graphviz dot program must be installed in your path.
func Layout(graph *gv.Graph, format string) ([]byte, error) {
f, err := ioutil.TempFile("", "gogp")
if err != nil {
return nil, err
}
// write to tmpfile
w := bufio.NewWriter(f)
fmt.Fprint(w, graph.String())
w.Flush()
f.Close()
file := f.Name()
defer os.Remove(file)
// process with dot
args := []string{file}
if format != "" {
args = append(args, "-T"+format)
}
var outData, errData bytes.Buffer
cmd := exec.Command("dot", args...)
cmd.Stdout = &outData
cmd.Stderr = &errData
if err := cmd.Run(); err != nil {
if errData.Len() > 0 {
err = errors.New(errData.String())
}
return nil, err
}
return outData.Bytes(), nil
}
