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// Copyright 2019 Nick White.
// Use of this source code is governed by the GPLv3
// license that can be found in the LICENSE file.
package hocr
// TODO: Parse line name to zero pad line numbers, so they can
// be sorted easily
import (
"fmt"
"image"
"image/draw"
_ "image/jpeg"
_ "image/png"
"io/ioutil"
"os"
"path/filepath"
"regexp"
"strings"
"rescribe.xyz/utils/pkg/line"
)
// Returns the image path for a page from a ocr_page title
func imagePathFromTitle(s string) (string, error) {
re, err := regexp.Compile(`image ["']([^"']+)["']`)
if err != nil {
return "", err
}
m := re.FindStringSubmatch(s)
return m[1], nil
}
// LineText extracts the text from an OcrLine
func LineText(l OcrLine) string {
linetext := ""
linetext = l.Text
if noText(linetext) {
linetext = ""
for _, w := range l.Words {
if w.Class != "ocrx_word" {
continue
}
linetext += w.Text + " "
}
}
if noText(linetext) {
linetext = ""
for _, w := range l.Words {
if w.Class != "ocrx_word" {
continue
}
for _, c := range w.Chars {
if c.Class != "ocrx_cinfo" {
continue
}
linetext += c.Text
}
linetext += " "
}
}
linetext = strings.TrimRight(linetext, " ")
return linetext
}
// parseLineDetails parses a Hocr struct into a line.Details
// struct, including extracted image segments for each line.
// The image location is taken from imgPath, which can either
// be imagePathFromTitle (see above) which loads the image
// path embedded in the title attribute of a hocr page, or
// a custom handler.
func parseLineDetails(h Hocr, dir string, imgPath func(string) (string, error)) (line.Details, error) {
lines := make(line.Details, 0)
for _, p := range h.Pages {
imgpath, err := imgPath(p.Title)
if err != nil {
return lines, err
}
imgpath = filepath.Join(dir, filepath.Base(imgpath))
var img image.Image
var gray *image.Gray
pngf, err := os.Open(imgpath)
if err != nil {
fmt.Fprintf(os.Stderr, "Warning: error opening image %s: %v\n", imgpath, err)
}
defer pngf.Close()
img, _, err = image.Decode(pngf)
if err == nil {
b := img.Bounds()
gray = image.NewGray(image.Rect(0, 0, b.Dx(), b.Dy()))
draw.Draw(gray, b, img, b.Min, draw.Src)
}
for _, l := range p.Lines {
totalconf := float64(0)
num := 0
for _, w := range l.Words {
c, err := wordConf(w.Title)
if err != nil {
return lines, err
}
num++
totalconf += c
}
coords, err := BoxCoords(l.Title)
if err != nil {
return lines, err
}
var ln line.Detail
ln.Name = l.Id
ln.Avgconf = (totalconf / float64(num)) / 100
ln.Text = LineText(l)
imgpath, err := imgPath(p.Title)
if err != nil {
return lines, err
}
ln.OcrName = strings.TrimSuffix(filepath.Base(imgpath), ".png")
if gray != nil {
var imgd line.ImgDirect
imgd.Img = gray.SubImage(image.Rect(coords[0], coords[1], coords[2], coords[3]))
ln.Img = imgd
}
lines = append(lines, ln)
}
pngf.Close()
}
return lines, nil
}
// GetLineDetails parses a hocr file and returns a corresponding
// line.Details, including image extracts for each line
func GetLineDetails(hocrfn string) (line.Details, error) {
var newlines line.Details
file, err := ioutil.ReadFile(hocrfn)
if err != nil {
return newlines, err
}
h, err := Parse(file)
if err != nil {
return newlines, err
}
return parseLineDetails(h, filepath.Dir(hocrfn), imagePathFromTitle)
}
// GetLineDetailsCustomImg is a variant of GetLineDetails that
// uses a provided image path for line image extracts, rather
// than the image name embedded in the .hocr
func GetLineDetailsCustomImg(hocrfn string, imgfn string) (line.Details, error) {
var newlines line.Details
file, err := ioutil.ReadFile(hocrfn)
if err != nil {
return newlines, err
}
h, err := Parse(file)
if err != nil {
return newlines, err
}
return parseLineDetails(h, filepath.Dir(hocrfn), func(s string) (string, error) { return imgfn, nil })
}
// GetLineBasics parses a hocr file and returns a corresponding
// line.Details, without any image extracts
func GetLineBasics(hocrfn string) (line.Details, error) {
var newlines line.Details
file, err := ioutil.ReadFile(hocrfn)
if err != nil {
return newlines, err
}
h, err := Parse(file)
if err != nil {
return newlines, err
}
return parseLineDetails(h, filepath.Dir(hocrfn), imagePathFromTitle)
}
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