Make confgraph and graph in general more resilient to bad input

2 files changed, 9 insertions, 1 deletions

diff --git a/cmd/confgraph/main.go b/cmd/confgraph/main.go
index 9b158f3..ed5ce93 100644
--- a/cmd/confgraph/main.go
+++ b/cmd/confgraph/main.go
@@ -22,6 +22,9 @@ func walker(confs *[]*bookpipeline.Conf) filepath.WalkFunc {
 		}
 		avg, err := hocr.GetAvgConf(path)
 		if err != nil {
+			if err.Error() == "No words found" {
+				return nil
+			}
 			return err
 		}
 		c := bookpipeline.Conf{
@@ -35,7 +38,7 @@ func walker(confs *[]*bookpipeline.Conf) filepath.WalkFunc {
 
 func main() {
 	flag.Usage = func() {
-		fmt.Fprintln(flag.CommandLine.Output(), "Usage: bookpipeline hocrdir graph.png")
+		fmt.Fprintln(flag.CommandLine.Output(), "Usage: confgraph hocrdir graph.png")
 		flag.PrintDefaults()
 	}
 	flag.Parse()
diff --git a/graph.go b/graph.go
index 955abbd..1604d06 100644
--- a/graph.go
+++ b/graph.go
@@ -1,6 +1,7 @@
 package bookpipeline
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"path/filepath"
@@ -61,6 +62,10 @@ func Graph(confs map[string]*Conf, bookname string, w io.Writer) error {
 	}
 	sort.Slice(graphconf, func(i, j int) bool { return graphconf[i].Pgnum < graphconf[j].Pgnum })
 
+	if len(graphconf) == 0 {
+		return errors.New("No valid confidences")
+	}
+
 	// Create main xvalues and yvalues, annotations and ticks
 	var xvalues, yvalues []float64
 	var annotations []chart.Value2