feat(docs): oo docs hocr — tesseract hOCR → go-hocr Markdown/YAML
Structured OCR path for agents alongside ocrmypdf searchable PDF. as-md --hocr selects the same pipeline for OO downloads. Co-authored-by: Cursor <cursoragent@cursor.com>
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Cursor
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package docpipe
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import (
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"bytes"
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"fmt"
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"os"
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"os/exec"
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"path/filepath"
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"strings"
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hocr "github.com/eslider/go-hocr"
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)
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// HOCRResult is structured OCR output for agents.
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type HOCRResult struct {
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HOCRPath string
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Markdown string
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YAML string
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DidOCR bool
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Source string
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}
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// ImageToHOCR runs tesseract hOCR into outBase+".hocr" (tesseract adds the extension).
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// outBase must not include ".hocr". dpi 0 uses tesseract default; phone photos often need 200–300.
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func (t Tools) ImageToHOCR(imgPath, outBase, lang string, dpi int) (string, error) {
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if t.Tesseract == "" {
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return "", fmt.Errorf("tesseract not found on PATH")
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}
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if lang == "" {
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lang = "eng"
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}
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if outBase == "" {
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return "", fmt.Errorf("hOCR output base path required")
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}
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args := []string{imgPath, outBase, "-l", lang}
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if dpi > 0 {
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args = append(args, "--dpi", fmt.Sprintf("%d", dpi))
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}
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args = append(args, resolveHOCRConfig())
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cmd := exec.Command(t.Tesseract, args...)
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var stderr bytes.Buffer
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cmd.Stderr = &stderr
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if err := cmd.Run(); err != nil {
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return "", fmt.Errorf("tesseract hocr: %w (%s)", err, strings.TrimSpace(stderr.String()))
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}
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out := outBase + ".hocr"
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if _, err := os.Stat(out); err != nil {
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// Some builds write .html
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alt := outBase + ".html"
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if _, err2 := os.Stat(alt); err2 == nil {
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return alt, nil
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}
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return "", fmt.Errorf("tesseract hocr: missing output %s (%s)", out, strings.TrimSpace(stderr.String()))
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}
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return out, nil
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}
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// resolveHOCRConfig returns a tesseract config path that works when TESSDATA_PREFIX
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// points at a custom traineddata dir without relative "hocr" configs.
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func resolveHOCRConfig() string {
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var candidates []string
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if p := strings.TrimSpace(os.Getenv("TESSDATA_PREFIX")); p != "" {
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candidates = append(candidates,
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filepath.Join(p, "configs", "hocr"),
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filepath.Join(p, "tessdata", "configs", "hocr"),
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)
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}
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candidates = append(candidates,
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"/usr/share/tesseract-ocr/5/tessdata/configs/hocr",
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"/usr/share/tesseract-ocr/4.00/tessdata/configs/hocr",
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"/usr/share/tessdata/configs/hocr",
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)
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for _, c := range candidates {
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if _, err := os.Stat(c); err == nil {
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return c
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}
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}
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return "hocr"
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}
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// HOCRToMarkdown parses an hOCR file via go-hocr and returns Markdown (+ optional YAML).
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// Words with confidence in (0, minConf) are dropped; minConf 0 keeps all.
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func HOCRToMarkdown(hocrPath string, minConf float32) (md string, yml string, err error) {
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doc, err := hocr.ReadFile(hocrPath)
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if err != nil {
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return "", "", fmt.Errorf("go-hocr: %w", err)
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}
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md = doc.ToMarkdown(minConf)
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yml, err = doc.ToYaml()
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if err != nil {
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return md, "", err
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}
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return md, yml, nil
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}
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// ToHOCRMarkdown OCRs an image (or rasterizes first PDF page) to hOCR → Markdown/YAML.
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func (t Tools) ToHOCRMarkdown(path, workDir, lang string, dpi int, minConf float32) (HOCRResult, error) {
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res := HOCRResult{Source: path}
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if workDir == "" {
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workDir = os.TempDir()
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}
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ext := Ext(path)
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img := path
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switch ext {
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case ".jpg", ".jpeg", ".png", ".tif", ".tiff", ".webp", ".gif", ".bmp":
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// ok
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case ".pdf":
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raster, err := t.pdfFirstPagePNG(path, workDir)
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if err != nil {
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return res, err
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}
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img = raster
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if dpi == 0 {
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dpi = 300
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}
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default:
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return res, fmt.Errorf("hOCR path expects image or PDF, got %q", ext)
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}
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base := filepath.Join(workDir, trimExt(filepath.Base(path))+".hocr-out")
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hocrPath, err := t.ImageToHOCR(img, base, lang, dpi)
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if err != nil {
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return res, err
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}
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res.DidOCR = true
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res.HOCRPath = hocrPath
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md, yml, err := HOCRToMarkdown(hocrPath, minConf)
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if err != nil {
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return res, err
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}
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res.Markdown = wrapMD(filepath.Base(path), strings.TrimSpace(md))
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res.YAML = yml
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return res, nil
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}
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// pdfFirstPagePNG uses pdftoppm when available.
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func (t Tools) pdfFirstPagePNG(pdfPath, workDir string) (string, error) {
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pdftoppm, err := exec.LookPath("pdftoppm")
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if err != nil {
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return "", fmt.Errorf("pdftoppm not found (needed to rasterize PDF for hOCR)")
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}
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outBase := filepath.Join(workDir, trimExt(filepath.Base(pdfPath))+".page")
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cmd := exec.Command(pdftoppm, "-png", "-f", "1", "-singlefile", "-r", "200", pdfPath, outBase)
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var stderr bytes.Buffer
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cmd.Stderr = &stderr
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if err := cmd.Run(); err != nil {
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return "", fmt.Errorf("pdftoppm: %w (%s)", err, strings.TrimSpace(stderr.String()))
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}
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png := outBase + ".png"
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if _, err := os.Stat(png); err != nil {
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return "", fmt.Errorf("pdftoppm: missing %s", png)
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}
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return png, nil
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}
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@@ -0,0 +1,49 @@
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package docpipe
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import (
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"os"
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"path/filepath"
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"strings"
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"testing"
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)
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func TestHOCRToMarkdown_Fixture(t *testing.T) {
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// Minimal hOCR 1.2 snippet
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hocrXML := `<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<title>tesseract</title>
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<meta http-equiv="Content-Type" content="text/html;charset=utf-8"/>
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<meta name="ocr-system" content="tesseract 5"/>
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<meta name="ocr-capabilities" content="ocr_page ocr_carea ocr_par ocr_line ocrx_word"/>
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</head>
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<body>
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<div class="ocr_page" id="page_1" title="image "x.png"; bbox 0 0 100 50; ppageno 0">
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<div class="ocr_carea" id="block_1_1" title="bbox 0 0 100 50">
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<p class="ocr_par" id="par_1_1" lang="eng" title="bbox 0 0 100 50">
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<span class="ocr_line" id="line_1_1" title="bbox 0 0 100 20; baseline 0 0; x_size 20">
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<span class="ocrx_word" id="word_1_1" title="bbox 0 0 40 20; x_wconf 96">Hello</span>
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<span class="ocrx_word" id="word_1_2" title="bbox 45 0 100 20; x_wconf 92">world</span>
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</span>
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</p>
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</div>
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</div>
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</body>
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</html>`
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dir := t.TempDir()
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p := filepath.Join(dir, "sample.hocr")
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if err := os.WriteFile(p, []byte(hocrXML), 0o644); err != nil {
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t.Fatal(err)
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}
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md, yml, err := HOCRToMarkdown(p, 0)
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if err != nil {
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t.Fatal(err)
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}
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if !strings.Contains(md, "Hello") || !strings.Contains(md, "world") {
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t.Fatalf("md=%q", md)
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}
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if !strings.Contains(yml, "Hello") {
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t.Fatalf("yaml missing word: %s", yml)
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}
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}
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