Add extracthocrlines tool

1 files changed, 89 insertions, 0 deletions

diff --git a/cmd/extracthocrlines/main.go b/cmd/extracthocrlines/main.go
new file mode 100644
index 0000000..d765875
--- /dev/null
+++ b/cmd/extracthocrlines/main.go
@@ -0,0 +1,89 @@
+// Copyright 2021 Nick White.
+// Use of this source code is governed by the GPLv3
+// license that can be found in the LICENSE file.
+
+// extracthocrlines copies the text and corresponding image section
+// for each line of a HOCR file into separate files, which is
+// useful for OCR training
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+
+	"rescribe.xyz/utils/pkg/hocr"
+	"rescribe.xyz/utils/pkg/line"
+)
+
+const usage = `Usage: extracthocrlines file.hocr [file.hocr]
+
+Copies the text and corresponding image section for each line
+of a HOCR file into separate files, which is useful for OCR
+training.
+`
+
+// saveline saves the text and image for a line in a directory
+func saveline(l line.Detail, dir string) error {
+	err := os.MkdirAll(dir, 0700)
+	if err != nil {
+		return err
+	}
+
+	base := filepath.Join(dir, l.OcrName+"_"+l.Name)
+
+	f, err := os.Create(base + ".png")
+	if err != nil {
+		return fmt.Errorf("Error creating file %s: %v", base+".png", err)
+	}
+
+	err = l.Img.CopyLineTo(f)
+	if err != nil {
+		return fmt.Errorf("Error writing line image for %s: %v", base+".png", err)
+	}
+
+	f, err = os.Create(base + ".txt")
+	if err != nil {
+		return fmt.Errorf("Error creating file %s: %v", base+".txt", err)
+	}
+
+	_, err = io.WriteString(f, l.Text)
+	if err != nil {
+		return fmt.Errorf("Error writing line text for %s: %v", base+".txt", err)
+	}
+
+	return nil
+}
+
+func main() {
+	flag.Usage = func() {
+		fmt.Fprintf(flag.CommandLine.Output(), usage)
+		flag.PrintDefaults()
+	}
+	dir := flag.String("d", ".", "Directory to save lines in")
+	flag.Parse()
+	if flag.NArg() < 1 {
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	for _, f := range flag.Args() {
+		newlines, err := hocr.GetLineDetails(f)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		for _, l := range newlines {
+			if l.Img == nil {
+				continue
+			}
+			err = saveline(l, *dir)
+			if err != nil {
+				log.Fatal(err)
+			}
+		}
+	}
+}