accept -graph-type

config.go

@@ -16,6 +16,9 @@ import (
 type Config struct {
 	Data   Data
 	Output url.URL
+	Graph  struct {
+		Type string
+	}
 }
 
 type Data struct {
@@ -36,7 +39,8 @@ func newConfig() (Config, error) {
 	dataWeightFloor := envOr("DATA_WEIGHT_FLOOR", `12`)
 	dataTitle := envOr("DATA_TITLE", ``)
 	dataSubtitle := envOr("DATA_SUBTITLE", ``)
-	output := envOr("OUTPUT", `file:///tmp/f`)
+	output := envOr("OUTPUT", `file:///tmp/f.html`)
+	graphType := envOr("GRAPH_TYPE", `scatter`)
 
 	fs := flag.NewFlagSet("cmd", flag.ContinueOnError)
 	fs.StringVar(&dataPoints, "data-points", dataPoints, `JSON [[x, y, z, ...]]`)
@@ -46,6 +50,7 @@ func newConfig() (Config, error) {
 	fs.StringVar(&dataTitle, "data-title", dataTitle, `chart title`)
 	fs.StringVar(&dataSubtitle, "data-subtitle", dataSubtitle, `chart subtitle`)
 	fs.StringVar(&output, "output", output, `scheme://location`)
+	fs.StringVar(&graphType, "graph-type", graphType, `[scatter, line]`)
 	if err := fs.Parse(os.Args[1:]); err != nil {
 		return Config{}, err
 	}
@@ -89,6 +94,7 @@ func newConfig() (Config, error) {
 
 	result.Data.Title = dataTitle
 	result.Data.Subtitle = dataSubtitle
+	result.Graph.Type = graphType
 
 	if u, err := url.Parse(output); err != nil {
 		return result, fmt.Errorf("failed to parse $OUTPUT (%s): %w", output, err)
@@ -106,6 +112,17 @@ func envOr(k, v string) string {
 	return v
 }
 
+func scatterAsLineData(data []opts.ScatterData) []opts.LineData {
+	result := make([]opts.LineData, len(data))
+	for i := range data {
+		result[i] = opts.LineData{
+			Value:      data[i].Value,
+			SymbolSize: data[i].SymbolSize,
+		}
+	}
+	return result
+}
+
 func (d Data) AsScatterData() (string, string, []opts.ScatterData, error) {
 	if !(2 <= len(d.Labels) && len(d.Labels) <= 3) {
 		return "", "", nil, fmt.Errorf("cannot map %d dimensions to [2,3]", len(d.Labels))

main.go

@@ -64,8 +64,7 @@ func run(ctx context.Context) error {
 	}
 	log.Printf("x=[%v, %v] y=[%v, %v]", minX, maxX, minY, maxY)
 
-	scatter := charts.NewScatter()
-	scatter.SetGlobalOptions(
+	globalOpts := []charts.GlobalOpts{
 		charts.WithTitleOpts(opts.Title{
 			Title:    config.Data.Title,
 			Subtitle: config.Data.Subtitle,
@@ -89,13 +88,26 @@ func run(ctx context.Context) error {
 			Min:          minY,
 			Max:          maxY,
 		}),
-	)
-	scatter.AddSeries(y, data)
+	}
 
 	buff := bytes.NewBuffer(nil)
+
+	switch config.Graph.Type {
+	case "line":
+		line := charts.NewLine()
+		line.SetGlobalOptions(globalOpts...)
+		line.AddSeries(y, scatterAsLineData(data))
+		if err := line.Render(buff); err != nil {
+			return err
+		}
+	case "scatter":
+		scatter := charts.NewScatter()
+		scatter.SetGlobalOptions(globalOpts...)
+		scatter.AddSeries(y, data)
 		if err := scatter.Render(buff); err != nil {
 			return err
 		}
+	}
 
 	switch config.Output.Scheme {
 	case "file":